Merge branch 'master' into llvm9

doc/langref.html.in

@@ -6379,7 +6379,7 @@ comptime {
       {#header_close#}
 
       {#header_open|@asyncCall#}
-      <pre>{#syntax#}@asyncCall(frame_buffer: []u8, result_ptr, function_ptr, args: ...) anyframe->T{#endsyntax#}</pre>
+      <pre>{#syntax#}@asyncCall(frame_buffer: []align(@alignOf(@Frame(anyAsyncFunction))) u8, result_ptr, function_ptr, args: ...) anyframe->T{#endsyntax#}</pre>
       <p>
       {#syntax#}@asyncCall{#endsyntax#} performs an {#syntax#}async{#endsyntax#} call on a function pointer,
       which may or may not be an {#link|async function|Async Functions#}.
@@ -6405,7 +6405,7 @@ test "async fn pointer in a struct field" {
         bar: async fn (*i32) void,
     };
     var foo = Foo{ .bar = func };
-    var bytes: [64]u8 = undefined;
+    var bytes: [64]u8 align(@alignOf(@Frame(func))) = undefined;
     const f = @asyncCall(&bytes, {}, foo.bar, &data);
     assert(data == 2);
     resume f;
@@ -7322,17 +7322,22 @@ mem.set(u8, dest, c);{#endsyntax#}</pre>
       {#header_close#}
 
       {#header_open|@newStackCall#}
-      <pre>{#syntax#}@newStackCall(new_stack: []u8, function: var, args: ...) var{#endsyntax#}</pre>
+      <pre>{#syntax#}@newStackCall(new_stack: []align(target_stack_align) u8, function: var, args: ...) var{#endsyntax#}</pre>
       <p>
       This calls a function, in the same way that invoking an expression with parentheses does. However,
       instead of using the same stack as the caller, the function uses the stack provided in the {#syntax#}new_stack{#endsyntax#}
       parameter.
       </p>
+      <p>
+      The new stack must be aligned to {#syntax#}target_stack_align{#endsyntax#} bytes. This is a target-specific
+      number. A safe value that will work on all targets is {#syntax#}16{#endsyntax#}. This value can
+      also be obtained by using {#link|@sizeOf#} on the {#link|@Frame#} type of {#link|Async Functions#}.
+      </p>
       {#code_begin|test#}
 const std = @import("std");
 const assert = std.debug.assert;
 
-var new_stack_bytes: [1024]u8 = undefined;
+var new_stack_bytes: [1024]u8 align(16) = undefined;
 
 test "calling a function with a new stack" {
     const arg = 1234;
@@ -9318,6 +9323,13 @@ const c = @cImport({
         <li>Does not support Zig-only pointer attributes such as alignment. Use normal {#link|Pointers#}
         please!</li>
       </ul>
+      <p>When a C pointer is pointing to a single struct (not an array), deference the C pointer to 
+        access to the struct's fields or member data. That syntax looks like 
+        this: </p>
+        <p>{#syntax#}ptr_to_struct.*.struct_member{#endsyntax#}</p>
+        <p>This is comparable to doing {#syntax#}->{#endsyntax#} in C.</p>
+        <p> When a C pointer is pointing to an array of structs, the syntax reverts to this:</p>
+        <p>{#syntax#}ptr_to_struct_array[index].struct_member{#endsyntax#}</p>
       {#header_close#}
 
       {#header_open|Exporting a C Library#}

src/all_types.hpp

@@ -1279,6 +1279,12 @@ struct ZigTypeOpaque {
 struct ZigTypeFnFrame {
     ZigFn *fn;
     ZigType *locals_struct;
+
+    // This is set to the type that resolving the frame currently depends on, null if none.
+    // It's for generating a helpful error message.
+    ZigType *resolve_loop_type;
+    AstNode *resolve_loop_src_node;
+    bool reported_loop_err;
 };
 
 struct ZigTypeAnyFrame {
@@ -1396,6 +1402,7 @@ struct ZigFn {
     AstNode *set_cold_node;
     const AstNode *inferred_async_node;
     ZigFn *inferred_async_fn;
+    AstNode *non_async_node;
 
     ZigList<GlobalExport> export_list;
     ZigList<IrInstructionCallGen *> call_list;

src/analyze.cpp

@@ -4144,8 +4144,15 @@ void semantic_analyze(CodeGen *g) {
 
     // second pass over functions for detecting async
     for (g->fn_defs_index = 0; g->fn_defs_index < g->fn_defs.length; g->fn_defs_index += 1) {
-        ZigFn *fn_entry = g->fn_defs.at(g->fn_defs_index);
+        ZigFn *fn = g->fn_defs.at(g->fn_defs_index);
-        analyze_fn_async(g, fn_entry, true);
+        analyze_fn_async(g, fn, true);
+        if (fn_is_async(fn) && fn->non_async_node != nullptr) {
+            ErrorMsg *msg = add_node_error(g, fn->proto_node,
+                buf_sprintf("'%s' cannot be async", buf_ptr(&fn->symbol_name)));
+            add_error_note(g, msg, fn->non_async_node,
+                buf_sprintf("required to be non-async here"));
+            add_async_error_notes(g, msg, fn);
+        }
     }
 }
 
@@ -5190,6 +5197,27 @@ static ZigType *get_async_fn_type(CodeGen *g, ZigType *orig_fn_type) {
     return fn_type;
 }
 
+static void emit_error_notes_for_type_loop(CodeGen *g, ErrorMsg *msg, ZigType *stop_type,
+        ZigType *ty, AstNode *src_node)
+{
+    ErrorMsg *note = add_error_note(g, msg, src_node,
+        buf_sprintf("when analyzing type '%s' here", buf_ptr(&ty->name)));
+    if (ty == stop_type)
+        return;
+    switch (ty->id) {
+        case ZigTypeIdFnFrame: {
+            ty->data.frame.reported_loop_err = true;
+            ZigType *depending_type = ty->data.frame.resolve_loop_type;
+            if (depending_type == nullptr)
+                return;
+            emit_error_notes_for_type_loop(g, note, stop_type,
+                depending_type, ty->data.frame.resolve_loop_src_node);
+        }
+        default:
+            return;
+    }
+}
+
 static Error resolve_async_frame(CodeGen *g, ZigType *frame_type) {
     Error err;
 
@@ -5199,6 +5227,20 @@ static Error resolve_async_frame(CodeGen *g, ZigType *frame_type) {
     ZigFn *fn = frame_type->data.frame.fn;
     assert(!fn->type_entry->data.fn.is_generic);
 
+    if (frame_type->data.frame.resolve_loop_type != nullptr) {
+        if (!frame_type->data.frame.reported_loop_err) {
+            frame_type->data.frame.reported_loop_err = true;
+            ErrorMsg *msg = add_node_error(g, fn->proto_node,
+                    buf_sprintf("'%s' depends on itself", buf_ptr(&frame_type->name)));
+            emit_error_notes_for_type_loop(g, msg,
+                    frame_type,
+                    frame_type->data.frame.resolve_loop_type,
+                    frame_type->data.frame.resolve_loop_src_node);
+            emit_error_notes_for_ref_stack(g, msg);
+        }
+        return ErrorSemanticAnalyzeFail;
+    }
+
     switch (fn->anal_state) {
         case FnAnalStateInvalid:
             return ErrorSemanticAnalyzeFail;
@@ -5292,6 +5334,10 @@ static Error resolve_async_frame(CodeGen *g, ZigType *frame_type) {
             return ErrorSemanticAnalyzeFail;
         }
 
+        ZigType *callee_frame_type = get_fn_frame_type(g, callee);
+        frame_type->data.frame.resolve_loop_type = callee_frame_type;
+        frame_type->data.frame.resolve_loop_src_node = call->base.source_node;
+
         analyze_fn_body(g, callee);
         if (callee->anal_state == FnAnalStateInvalid) {
             frame_type->data.frame.locals_struct = g->builtin_types.entry_invalid;
@@ -5301,8 +5347,6 @@ static Error resolve_async_frame(CodeGen *g, ZigType *frame_type) {
         if (!fn_is_async(callee))
             continue;
 
-        ZigType *callee_frame_type = get_fn_frame_type(g, callee);
-
         IrInstructionAllocaGen *alloca_gen = allocate<IrInstructionAllocaGen>(1);
         alloca_gen->base.id = IrInstructionIdAllocaGen;
         alloca_gen->base.source_node = call->base.source_node;
@@ -5371,9 +5415,13 @@ static Error resolve_async_frame(CodeGen *g, ZigType *frame_type) {
                 continue;
             }
         }
+
+        frame_type->data.frame.resolve_loop_type = child_type;
+        frame_type->data.frame.resolve_loop_src_node = instruction->base.source_node;
         if ((err = type_resolve(g, child_type, ResolveStatusSizeKnown))) {
             return err;
         }
+
         const char *name;
         if (*instruction->name_hint == 0) {
             name = buf_ptr(buf_sprintf("@local%" ZIG_PRI_usize, alloca_i));

src/ir.cpp

@@ -6743,6 +6743,25 @@ static Error parse_asm_template(IrBuilder *irb, AstNode *source_node, Buf *asm_t
     return ErrorNone;
 }
 
+static size_t find_asm_index(CodeGen *g, AstNode *node, AsmToken *tok, Buf *src_template) {
+    const char *ptr = buf_ptr(src_template) + tok->start + 2;
+    size_t len = tok->end - tok->start - 2;
+    size_t result = 0;
+    for (size_t i = 0; i < node->data.asm_expr.output_list.length; i += 1, result += 1) {
+        AsmOutput *asm_output = node->data.asm_expr.output_list.at(i);
+        if (buf_eql_mem(asm_output->asm_symbolic_name, ptr, len)) {
+            return result;
+        }
+    }
+    for (size_t i = 0; i < node->data.asm_expr.input_list.length; i += 1, result += 1) {
+        AsmInput *asm_input = node->data.asm_expr.input_list.at(i);
+        if (buf_eql_mem(asm_input->asm_symbolic_name, ptr, len)) {
+            return result;
+        }
+    }
+    return SIZE_MAX;
+}
+
 static IrInstruction *ir_gen_asm_expr(IrBuilder *irb, Scope *scope, AstNode *node) {
     Error err;
     assert(node->type == NodeTypeAsmExpr);
@@ -6830,6 +6849,22 @@ static IrInstruction *ir_gen_asm_expr(IrBuilder *irb, Scope *scope, AstNode *nod
         input_list[i] = input_value;
     }
 
+    for (size_t token_i = 0; token_i < tok_list.length; token_i += 1) {
+        AsmToken asm_token = tok_list.at(token_i);
+        if (asm_token.id == AsmTokenIdVar) {
+            size_t index = find_asm_index(irb->codegen, node, &asm_token, template_buf);
+            if (index == SIZE_MAX) {
+                const char *ptr = buf_ptr(template_buf) + asm_token.start + 2;
+                uint32_t len = asm_token.end - asm_token.start - 2;
+
+                add_node_error(irb->codegen, node,
+                    buf_sprintf("could not find '%.*s' in the inputs or outputs.",
+                        len, ptr));
+                return irb->codegen->invalid_instruction;
+            }
+        }
+    }
+
     return ir_build_asm(irb, scope, node, template_buf, tok_list.items, tok_list.length,
             input_list, output_types, output_vars, return_count, is_volatile);
 }
@@ -9485,10 +9520,6 @@ static ConstCastOnly types_match_const_cast_only(IrAnalyze *ira, ZigType *wanted
             result.id = ConstCastResultIdFnAlign;
             return result;
         }
-        if (wanted_type->data.fn.fn_type_id.cc != actual_type->data.fn.fn_type_id.cc) {
-            result.id = ConstCastResultIdFnCC;
-            return result;
-        }
         if (wanted_type->data.fn.fn_type_id.is_var_args != actual_type->data.fn.fn_type_id.is_var_args) {
             result.id = ConstCastResultIdFnVarArgs;
             return result;
@@ -9546,6 +9577,11 @@ static ConstCastOnly types_match_const_cast_only(IrAnalyze *ira, ZigType *wanted
                 return result;
             }
         }
+        if (wanted_type->data.fn.fn_type_id.cc != actual_type->data.fn.fn_type_id.cc) {
+            // ConstCastResultIdFnCC is guaranteed to be the last one reported, meaning everything else is ok.
+            result.id = ConstCastResultIdFnCC;
+            return result;
+        }
         return result;
     }
 
@@ -11780,8 +11816,11 @@ static void report_recursive_error(IrAnalyze *ira, AstNode *source_node, ConstCa
             add_error_note(ira->codegen, parent_msg, source_node,
                     buf_sprintf("only one of the functions is generic"));
             break;
+        case ConstCastResultIdFnCC:
+            add_error_note(ira->codegen, parent_msg, source_node,
+                    buf_sprintf("calling convention mismatch"));
+            break;
         case ConstCastResultIdFnAlign: // TODO
-        case ConstCastResultIdFnCC: // TODO
         case ConstCastResultIdFnVarArgs: // TODO
         case ConstCastResultIdFnReturnType: // TODO
         case ConstCastResultIdFnArgCount: // TODO
@@ -11891,6 +11930,21 @@ static IrInstruction *ir_analyze_cast(IrAnalyze *ira, IrInstruction *source_inst
         return ir_resolve_cast(ira, source_instr, value, wanted_type, CastOpNoop);
     }
 
+    if (const_cast_result.id == ConstCastResultIdFnCC) {
+        ir_assert(value->value.type->id == ZigTypeIdFn, source_instr);
+        // ConstCastResultIdFnCC is guaranteed to be the last one reported, meaning everything else is ok.
+        if (wanted_type->data.fn.fn_type_id.cc == CallingConventionAsync &&
+            actual_type->data.fn.fn_type_id.cc == CallingConventionUnspecified)
+        {
+            ir_assert(value->value.data.x_ptr.special == ConstPtrSpecialFunction, source_instr);
+            ZigFn *fn = value->value.data.x_ptr.data.fn.fn_entry;
+            if (fn->inferred_async_node == nullptr) {
+                fn->inferred_async_node = source_instr->source_node;
+            }
+            return ir_resolve_cast(ira, source_instr, value, wanted_type, CastOpNoop);
+        }
+    }
+
     // cast from T to ?T
     // note that the *T to ?*T case is handled via the "ConstCastOnly" mechanism
     if (wanted_type->id == ZigTypeIdOptional) {
@@ -12110,7 +12164,26 @@ static IrInstruction *ir_analyze_cast(IrAnalyze *ira, IrInstruction *source_inst
             array_type->data.array.child_type, source_node,
             !slice_ptr_type->data.pointer.is_const).id == ConstCastResultIdOk)
         {
-            return ir_resolve_ptr_of_array_to_slice(ira, source_instr, value, wanted_type, result_loc);
+            // If the pointers both have ABI align, it works.
+            bool ok_align = slice_ptr_type->data.pointer.explicit_alignment == 0 &&
+                actual_type->data.pointer.explicit_alignment == 0;
+            if (!ok_align) {
+                // If either one has non ABI align, we have to resolve them both
+                if ((err = type_resolve(ira->codegen, actual_type->data.pointer.child_type,
+                                ResolveStatusAlignmentKnown)))
+                {
+                    return ira->codegen->invalid_instruction;
+                }
+                if ((err = type_resolve(ira->codegen, slice_ptr_type->data.pointer.child_type,
+                                ResolveStatusAlignmentKnown)))
+                {
+                    return ira->codegen->invalid_instruction;
+                }
+                ok_align = get_ptr_align(ira->codegen, actual_type) >= get_ptr_align(ira->codegen, slice_ptr_type);
+            }
+            if (ok_align) {
+                return ir_resolve_ptr_of_array_to_slice(ira, source_instr, value, wanted_type, result_loc);
+            }
         }
     }
 
@@ -13902,8 +13975,7 @@ static IrInstruction *ir_analyze_array_mult(IrAnalyze *ira, IrInstructionBinOp *
     uint64_t old_array_len = array_type->data.array.len;
     uint64_t new_array_len;
 
-    if (mul_u64_overflow(old_array_len, mult_amt, &new_array_len))
+    if (mul_u64_overflow(old_array_len, mult_amt, &new_array_len)) {
-    {
         ir_add_error(ira, &instruction->base, buf_sprintf("operation results in overflow"));
         return ira->codegen->invalid_instruction;
     }
@@ -13918,6 +13990,15 @@ static IrInstruction *ir_analyze_array_mult(IrAnalyze *ira, IrInstructionBinOp *
         return result;
     }
 
+    switch (type_has_one_possible_value(ira->codegen, result->value.type)) {
+        case OnePossibleValueInvalid:
+            return ira->codegen->invalid_instruction;
+        case OnePossibleValueYes:
+            return result;
+        case OnePossibleValueNo:
+            break;
+    }
+
     // TODO optimize the buf case
     expand_undef_array(ira->codegen, array_val);
     out_val->data.x_array.data.s_none.elements = create_const_vals(new_array_len);
@@ -13925,8 +14006,11 @@ static IrInstruction *ir_analyze_array_mult(IrAnalyze *ira, IrInstructionBinOp *
     uint64_t i = 0;
     for (uint64_t x = 0; x < mult_amt; x += 1) {
         for (uint64_t y = 0; y < old_array_len; y += 1) {
-            copy_const_val(&out_val->data.x_array.data.s_none.elements[i],
+            ConstExprValue *elem_dest_val = &out_val->data.x_array.data.s_none.elements[i];
-                &array_val->data.x_array.data.s_none.elements[y], false);
+            copy_const_val(elem_dest_val, &array_val->data.x_array.data.s_none.elements[y], false);
+            elem_dest_val->parent.id = ConstParentIdArray;
+            elem_dest_val->parent.data.p_array.array_val = out_val;
+            elem_dest_val->parent.data.p_array.elem_index = i;
             i += 1;
         }
     }
@@ -14753,6 +14837,9 @@ static IrInstruction *ir_resolve_result_raw(IrAnalyze *ira, IrInstruction *suspe
                 return ira->codegen->invalid_instruction;
             }
             uint64_t parent_ptr_align = get_ptr_align(ira->codegen, parent_ptr_type);
+            if ((err = type_resolve(ira->codegen, value_type, ResolveStatusAlignmentKnown))) {
+                return ira->codegen->invalid_instruction;
+            }
             ZigType *ptr_type = get_pointer_to_type_extra(ira->codegen, value_type,
                     parent_ptr_type->data.pointer.is_const, parent_ptr_type->data.pointer.is_volatile, PtrLenSingle,
                     parent_ptr_align, 0, 0, parent_ptr_type->data.pointer.allow_zero);
@@ -15141,6 +15228,20 @@ no_mem_slot:
     return var_ptr_instruction;
 }
 
+// This function is called when a comptime value becomes accessible at runtime.
+static void mark_comptime_value_escape(IrAnalyze *ira, IrInstruction *source_instr, ConstExprValue *val) {
+    ir_assert(value_is_comptime(val), source_instr);
+    if (val->special == ConstValSpecialUndef)
+        return;
+
+    if (val->type->id == ZigTypeIdFn && val->type->data.fn.fn_type_id.cc == CallingConventionUnspecified) {
+        ir_assert(val->data.x_ptr.special == ConstPtrSpecialFunction, source_instr);
+        if (val->data.x_ptr.data.fn.fn_entry->non_async_node == nullptr) {
+            val->data.x_ptr.data.fn.fn_entry->non_async_node = source_instr->source_node;
+        }
+    }
+}
+
 static IrInstruction *ir_analyze_store_ptr(IrAnalyze *ira, IrInstruction *source_instr,
         IrInstruction *ptr, IrInstruction *uncasted_value, bool allow_write_through_const)
 {
@@ -15237,6 +15338,10 @@ static IrInstruction *ir_analyze_store_ptr(IrAnalyze *ira, IrInstruction *source
             break;
     }
 
+    if (instr_is_comptime(value)) {
+        mark_comptime_value_escape(ira, source_instr, &value->value);
+    }
+
     IrInstructionStorePtr *store_ptr = ir_build_store_ptr(&ira->new_irb, source_instr->scope,
             source_instr->source_node, ptr, value);
     return &store_ptr->base;
@@ -15421,7 +15526,7 @@ static IrInstruction *ir_analyze_fn_call(IrAnalyze *ira, IrInstructionCallSrc *c
     IrInstruction *casted_new_stack = nullptr;
     if (call_instruction->new_stack != nullptr) {
         ZigType *u8_ptr = get_pointer_to_type_extra(ira->codegen, ira->codegen->builtin_types.entry_u8,
-                false, false, PtrLenUnknown, 0, 0, 0, false);
+                false, false, PtrLenUnknown, target_fn_align(ira->codegen->zig_target), 0, 0, false);
         ZigType *u8_slice = get_slice_type(ira->codegen, u8_ptr);
         IrInstruction *new_stack = call_instruction->new_stack->child;
         if (type_is_invalid(new_stack->value.type))
@@ -17123,7 +17228,7 @@ static void add_link_lib_symbol(IrAnalyze *ira, Buf *lib_name, Buf *symbol_name,
             buf_sprintf("dependency on dynamic library '%s' requires enabling Position Independent Code",
                 buf_ptr(lib_name)));
         add_error_note(ira->codegen, msg, source_node,
-                buf_sprintf("fixed by `--library %s` or `--enable-pic`", buf_ptr(lib_name)));
+                buf_sprintf("fixed by `--library %s` or `-fPIC`", buf_ptr(lib_name)));
         ira->codegen->reported_bad_link_libc_error = true;
     }
 
@@ -20841,6 +20946,12 @@ static IrInstruction *ir_analyze_instruction_fence(IrAnalyze *ira, IrInstruction
     if (!ir_resolve_atomic_order(ira, order_value, &order))
         return ira->codegen->invalid_instruction;
 
+    if (order < AtomicOrderAcquire) {
+        ir_add_error(ira, order_value,
+                buf_sprintf("atomic ordering must be Acquire or stricter"));
+        return ira->codegen->invalid_instruction;
+    }
+
     IrInstruction *result = ir_build_fence(&ira->new_irb,
         instruction->base.scope, instruction->base.source_node, order_value, order);
     result->value.type = ira->codegen->builtin_types.entry_void;
@@ -24491,7 +24602,11 @@ static IrInstruction *ir_analyze_instruction_bit_cast_src(IrAnalyze *ira, IrInst
     if (result_loc != nullptr && (type_is_invalid(result_loc->value.type) || instr_is_unreachable(result_loc)))
         return result_loc;
 
-    return instruction->result_loc_bit_cast->parent->gen_instruction;
+    if (instruction->result_loc_bit_cast->parent->gen_instruction != nullptr) {
+        return instruction->result_loc_bit_cast->parent->gen_instruction;
+    }
+
+    return result_loc;
 }
 
 static IrInstruction *ir_analyze_instruction_union_init_named_field(IrAnalyze *ira,

src/link.cpp

@@ -1755,7 +1755,7 @@ static void construct_linker_job_elf(LinkJob *lj) {
 
 
     // libc dep
-    if (g->libc_link_lib != nullptr) {
+    if (g->libc_link_lib != nullptr && g->out_type != OutTypeObj) {
         if (g->libc != nullptr) {
             if (!g->have_dynamic_link) {
                 lj->args.append("--start-group");

std/c.zig

@@ -55,6 +55,7 @@ pub extern "c" fn fclose(stream: *FILE) c_int;
 pub extern "c" fn fwrite(ptr: [*]const u8, size_of_type: usize, item_count: usize, stream: *FILE) usize;
 pub extern "c" fn fread(ptr: [*]u8, size_of_type: usize, item_count: usize, stream: *FILE) usize;
 
+pub extern "c" fn printf(format: [*]const u8, ...) c_int;
 pub extern "c" fn abort() noreturn;
 pub extern "c" fn exit(code: c_int) noreturn;
 pub extern "c" fn isatty(fd: fd_t) c_int;
@@ -64,10 +65,12 @@ pub extern "c" fn fstat(fd: fd_t, buf: *Stat) c_int;
 pub extern "c" fn @"fstat$INODE64"(fd: fd_t, buf: *Stat) c_int;
 pub extern "c" fn lseek(fd: fd_t, offset: isize, whence: c_int) isize;
 pub extern "c" fn open(path: [*]const u8, oflag: c_uint, ...) c_int;
+pub extern "c" fn openat(fd: c_int, path: [*]const u8, oflag: c_uint, ...) c_int;
 pub extern "c" fn raise(sig: c_int) c_int;
 pub extern "c" fn read(fd: fd_t, buf: [*]u8, nbyte: usize) isize;
 pub extern "c" fn pread(fd: fd_t, buf: [*]u8, nbyte: usize, offset: u64) isize;
 pub extern "c" fn preadv(fd: c_int, iov: [*]const iovec, iovcnt: c_uint, offset: usize) isize;
+pub extern "c" fn writev(fd: c_int, iov: [*]const iovec_const, iovcnt: c_uint) isize;
 pub extern "c" fn pwritev(fd: c_int, iov: [*]const iovec_const, iovcnt: c_uint, offset: usize) isize;
 pub extern "c" fn stat(noalias path: [*]const u8, noalias buf: *Stat) c_int;
 pub extern "c" fn write(fd: fd_t, buf: [*]const u8, nbyte: usize) isize;
@@ -112,7 +115,6 @@ pub extern "c" fn accept4(sockfd: fd_t, addr: *sockaddr, addrlen: *socklen_t, fl
 pub extern "c" fn getsockopt(sockfd: fd_t, level: c_int, optname: c_int, optval: *c_void, optlen: *socklen_t) c_int;
 pub extern "c" fn kill(pid: pid_t, sig: c_int) c_int;
 pub extern "c" fn getdirentries(fd: fd_t, buf_ptr: [*]u8, nbytes: usize, basep: *i64) isize;
-pub extern "c" fn openat(fd: c_int, path: [*]const u8, flags: c_int) c_int;
 pub extern "c" fn setgid(ruid: c_uint, euid: c_uint) c_int;
 pub extern "c" fn setuid(uid: c_uint) c_int;
 pub extern "c" fn clock_gettime(clk_id: c_int, tp: *timespec) c_int;

std/c/freebsd.zig

@@ -6,4 +6,4 @@ pub const _errno = __error;
 
 pub extern "c" fn getdents(fd: c_int, buf_ptr: [*]u8, nbytes: usize) usize;
 pub extern "c" fn sigaltstack(ss: ?*stack_t, old_ss: ?*stack_t) c_int;
-pub extern "c" fn getrandom(buf_ptr: [*]u8, buf_len: usize, flags: c_uint) c_int;
+pub extern "c" fn getrandom(buf_ptr: [*]u8, buf_len: usize, flags: c_uint) isize;

std/c/linux.zig

@@ -7,7 +7,7 @@ pub const _errno = __errno_location;
 
 pub const MAP_FAILED = @intToPtr(*c_void, maxInt(usize));
 
-pub extern "c" fn getrandom(buf_ptr: [*]u8, buf_len: usize, flags: c_uint) c_int;
+pub extern "c" fn getrandom(buf_ptr: [*]u8, buf_len: usize, flags: c_uint) isize;
 pub extern "c" fn sched_getaffinity(pid: c_int, size: usize, set: *cpu_set_t) c_int;
 pub extern "c" fn eventfd(initval: c_uint, flags: c_uint) c_int;
 pub extern "c" fn epoll_ctl(epfd: fd_t, op: c_uint, fd: fd_t, event: ?*epoll_event) c_int;

std/event/fs.zig

@@ -23,6 +23,7 @@ pub const Request = struct {
     };
 
     pub const Msg = union(enum) {
+        WriteV: WriteV,
         PWriteV: PWriteV,
         PReadV: PReadV,
         Open: Open,
@@ -30,6 +31,14 @@ pub const Request = struct {
         WriteFile: WriteFile,
         End, // special - means the fs thread should exit
 
+        pub const WriteV = struct {
+            fd: fd_t,
+            iov: []const os.iovec_const,
+            result: Error!void,
+
+            pub const Error = os.WriteError;
+        };
+
         pub const PWriteV = struct {
             fd: fd_t,
             iov: []const os.iovec_const,
@@ -77,7 +86,7 @@ pub const Request = struct {
 pub const PWriteVError = error{OutOfMemory} || File.WriteError;
 
 /// data - just the inner references - must live until pwritev frame completes.
-pub async fn pwritev(loop: *Loop, fd: fd_t, data: []const []const u8, offset: usize) PWriteVError!void {
+pub fn pwritev(loop: *Loop, fd: fd_t, data: []const []const u8, offset: usize) PWriteVError!void {
     switch (builtin.os) {
         .macosx,
         .linux,
@@ -94,31 +103,31 @@ pub async fn pwritev(loop: *Loop, fd: fd_t, data: []const []const u8, offset: us
                 };
             }
 
-            return await (async pwritevPosix(loop, fd, iovecs, offset) catch unreachable);
+            return pwritevPosix(loop, fd, iovecs, offset);
         },
         .windows => {
             const data_copy = try std.mem.dupe(loop.allocator, []const u8, data);
             defer loop.allocator.free(data_copy);
-            return await (async pwritevWindows(loop, fd, data, offset) catch unreachable);
+            return pwritevWindows(loop, fd, data, offset);
         },
         else => @compileError("Unsupported OS"),
     }
 }
 
 /// data must outlive the returned frame
-pub async fn pwritevWindows(loop: *Loop, fd: fd_t, data: []const []const u8, offset: usize) os.WindowsWriteError!void {
+pub fn pwritevWindows(loop: *Loop, fd: fd_t, data: []const []const u8, offset: usize) os.WindowsWriteError!void {
     if (data.len == 0) return;
-    if (data.len == 1) return await (async pwriteWindows(loop, fd, data[0], offset) catch unreachable);
+    if (data.len == 1) return pwriteWindows(loop, fd, data[0], offset);
 
     // TODO do these in parallel
     var off = offset;
     for (data) |buf| {
-        try await (async pwriteWindows(loop, fd, buf, off) catch unreachable);
+        try pwriteWindows(loop, fd, buf, off);
         off += buf.len;
     }
 }
 
-pub async fn pwriteWindows(loop: *Loop, fd: fd_t, data: []const u8, offset: u64) os.WindowsWriteError!void {
+pub fn pwriteWindows(loop: *Loop, fd: fd_t, data: []const u8, offset: u64) os.WindowsWriteError!void {
     var resume_node = Loop.ResumeNode.Basic{
         .base = Loop.ResumeNode{
             .id = Loop.ResumeNode.Id.Basic,
@@ -158,7 +167,7 @@ pub async fn pwriteWindows(loop: *Loop, fd: fd_t, data: []const u8, offset: u64)
 }
 
 /// iovecs must live until pwritev frame completes.
-pub async fn pwritevPosix(
+pub fn pwritevPosix(
     loop: *Loop,
     fd: fd_t,
     iovecs: []const os.iovec_const,
@@ -195,10 +204,44 @@ pub async fn pwritevPosix(
     return req_node.data.msg.PWriteV.result;
 }
 
+/// iovecs must live until pwritev frame completes.
+pub fn writevPosix(
+    loop: *Loop,
+    fd: fd_t,
+    iovecs: []const os.iovec_const,
+) os.WriteError!void {
+    var req_node = RequestNode{
+        .prev = null,
+        .next = null,
+        .data = Request{
+            .msg = Request.Msg{
+                .WriteV = Request.Msg.WriteV{
+                    .fd = fd,
+                    .iov = iovecs,
+                    .result = undefined,
+                },
+            },
+            .finish = Request.Finish{
+                .TickNode = Loop.NextTickNode{
+                    .prev = null,
+                    .next = null,
+                    .data = @frame(),
+                },
+            },
+        },
+    };
+
+    suspend {
+        loop.posixFsRequest(&req_node);
+    }
+
+    return req_node.data.msg.WriteV.result;
+}
+
 pub const PReadVError = error{OutOfMemory} || File.ReadError;
 
 /// data - just the inner references - must live until preadv frame completes.
-pub async fn preadv(loop: *Loop, fd: fd_t, data: []const []u8, offset: usize) PReadVError!usize {
+pub fn preadv(loop: *Loop, fd: fd_t, data: []const []u8, offset: usize) PReadVError!usize {
     assert(data.len != 0);
     switch (builtin.os) {
         .macosx,
@@ -216,21 +259,21 @@ pub async fn preadv(loop: *Loop, fd: fd_t, data: []const []u8, offset: usize) PR
                 };
             }
 
-            return await (async preadvPosix(loop, fd, iovecs, offset) catch unreachable);
+            return preadvPosix(loop, fd, iovecs, offset);
         },
         .windows => {
             const data_copy = try std.mem.dupe(loop.allocator, []u8, data);
             defer loop.allocator.free(data_copy);
-            return await (async preadvWindows(loop, fd, data_copy, offset) catch unreachable);
+            return preadvWindows(loop, fd, data_copy, offset);
         },
         else => @compileError("Unsupported OS"),
     }
 }
 
 /// data must outlive the returned frame
-pub async fn preadvWindows(loop: *Loop, fd: fd_t, data: []const []u8, offset: u64) !usize {
+pub fn preadvWindows(loop: *Loop, fd: fd_t, data: []const []u8, offset: u64) !usize {
     assert(data.len != 0);
-    if (data.len == 1) return await (async preadWindows(loop, fd, data[0], offset) catch unreachable);
+    if (data.len == 1) return preadWindows(loop, fd, data[0], offset);
 
     // TODO do these in parallel?
     var off: usize = 0;
@@ -238,7 +281,7 @@ pub async fn preadvWindows(loop: *Loop, fd: fd_t, data: []const []u8, offset: u6
     var inner_off: usize = 0;
     while (true) {
         const v = data[iov_i];
-        const amt_read = try await (async preadWindows(loop, fd, v[inner_off .. v.len - inner_off], offset + off) catch unreachable);
+        const amt_read = try preadWindows(loop, fd, v[inner_off .. v.len - inner_off], offset + off);
         off += amt_read;
         inner_off += amt_read;
         if (inner_off == v.len) {
@@ -252,7 +295,7 @@ pub async fn preadvWindows(loop: *Loop, fd: fd_t, data: []const []u8, offset: u6
     }
 }
 
-pub async fn preadWindows(loop: *Loop, fd: fd_t, data: []u8, offset: u64) !usize {
+pub fn preadWindows(loop: *Loop, fd: fd_t, data: []u8, offset: u64) !usize {
     var resume_node = Loop.ResumeNode.Basic{
         .base = Loop.ResumeNode{
             .id = Loop.ResumeNode.Id.Basic,
@@ -291,7 +334,7 @@ pub async fn preadWindows(loop: *Loop, fd: fd_t, data: []u8, offset: u64) !usize
 }
 
 /// iovecs must live until preadv frame completes
-pub async fn preadvPosix(
+pub fn preadvPosix(
     loop: *Loop,
     fd: fd_t,
     iovecs: []const os.iovec,
@@ -328,7 +371,7 @@ pub async fn preadvPosix(
     return req_node.data.msg.PReadV.result;
 }
 
-pub async fn openPosix(
+pub fn openPosix(
     loop: *Loop,
     path: []const u8,
     flags: u32,
@@ -367,11 +410,11 @@ pub async fn openPosix(
     return req_node.data.msg.Open.result;
 }
 
-pub async fn openRead(loop: *Loop, path: []const u8) File.OpenError!fd_t {
+pub fn openRead(loop: *Loop, path: []const u8) File.OpenError!fd_t {
     switch (builtin.os) {
         .macosx, .linux, .freebsd, .netbsd => {
             const flags = os.O_LARGEFILE | os.O_RDONLY | os.O_CLOEXEC;
-            return await (async openPosix(loop, path, flags, File.default_mode) catch unreachable);
+            return openPosix(loop, path, flags, File.default_mode);
         },
 
         .windows => return windows.CreateFile(
@@ -390,12 +433,12 @@ pub async fn openRead(loop: *Loop, path: []const u8) File.OpenError!fd_t {
 
 /// Creates if does not exist. Truncates the file if it exists.
 /// Uses the default mode.
-pub async fn openWrite(loop: *Loop, path: []const u8) File.OpenError!fd_t {
+pub fn openWrite(loop: *Loop, path: []const u8) File.OpenError!fd_t {
-    return await (async openWriteMode(loop, path, File.default_mode) catch unreachable);
+    return openWriteMode(loop, path, File.default_mode);
 }
 
 /// Creates if does not exist. Truncates the file if it exists.
-pub async fn openWriteMode(loop: *Loop, path: []const u8, mode: File.Mode) File.OpenError!fd_t {
+pub fn openWriteMode(loop: *Loop, path: []const u8, mode: File.Mode) File.OpenError!fd_t {
     switch (builtin.os) {
         .macosx,
         .linux,
@@ -403,7 +446,7 @@ pub async fn openWriteMode(loop: *Loop, path: []const u8, mode: File.Mode) File.
         .netbsd,
         => {
             const flags = os.O_LARGEFILE | os.O_WRONLY | os.O_CREAT | os.O_CLOEXEC | os.O_TRUNC;
-            return await (async openPosix(loop, path, flags, File.default_mode) catch unreachable);
+            return openPosix(loop, path, flags, File.default_mode);
         },
         .windows => return windows.CreateFile(
             path,
@@ -419,7 +462,7 @@ pub async fn openWriteMode(loop: *Loop, path: []const u8, mode: File.Mode) File.
 }
 
 /// Creates if does not exist. Does not truncate.
-pub async fn openReadWrite(
+pub fn openReadWrite(
     loop: *Loop,
     path: []const u8,
     mode: File.Mode,
@@ -427,7 +470,7 @@ pub async fn openReadWrite(
     switch (builtin.os) {
         .macosx, .linux, .freebsd, .netbsd => {
             const flags = os.O_LARGEFILE | os.O_RDWR | os.O_CREAT | os.O_CLOEXEC;
-            return await (async openPosix(loop, path, flags, mode) catch unreachable);
+            return openPosix(loop, path, flags, mode);
         },
 
         .windows => return windows.CreateFile(
@@ -576,24 +619,24 @@ pub const CloseOperation = struct {
 
 /// contents must remain alive until writeFile completes.
 /// TODO make this atomic or provide writeFileAtomic and rename this one to writeFileTruncate
-pub async fn writeFile(loop: *Loop, path: []const u8, contents: []const u8) !void {
+pub fn writeFile(loop: *Loop, path: []const u8, contents: []const u8) !void {
-    return await (async writeFileMode(loop, path, contents, File.default_mode) catch unreachable);
+    return writeFileMode(loop, path, contents, File.default_mode);
 }
 
 /// contents must remain alive until writeFile completes.
-pub async fn writeFileMode(loop: *Loop, path: []const u8, contents: []const u8, mode: File.Mode) !void {
+pub fn writeFileMode(loop: *Loop, path: []const u8, contents: []const u8, mode: File.Mode) !void {
     switch (builtin.os) {
         .linux,
         .macosx,
         .freebsd,
         .netbsd,
-        => return await (async writeFileModeThread(loop, path, contents, mode) catch unreachable),
+        => return writeFileModeThread(loop, path, contents, mode),
-        .windows => return await (async writeFileWindows(loop, path, contents) catch unreachable),
+        .windows => return writeFileWindows(loop, path, contents),
         else => @compileError("Unsupported OS"),
     }
 }
 
-async fn writeFileWindows(loop: *Loop, path: []const u8, contents: []const u8) !void {
+fn writeFileWindows(loop: *Loop, path: []const u8, contents: []const u8) !void {
     const handle = try windows.CreateFile(
         path,
         windows.GENERIC_WRITE,
@@ -605,10 +648,10 @@ async fn writeFileWindows(loop: *Loop, path: []const u8, contents: []const u8) !
     );
     defer os.close(handle);
 
-    try await (async pwriteWindows(loop, handle, contents, 0) catch unreachable);
+    try pwriteWindows(loop, handle, contents, 0);
 }
 
-async fn writeFileModeThread(loop: *Loop, path: []const u8, contents: []const u8, mode: File.Mode) !void {
+fn writeFileModeThread(loop: *Loop, path: []const u8, contents: []const u8, mode: File.Mode) !void {
     const path_with_null = try std.cstr.addNullByte(loop.allocator, path);
     defer loop.allocator.free(path_with_null);
 
@@ -646,11 +689,11 @@ async fn writeFileModeThread(loop: *Loop, path: []const u8, contents: []const u8
 /// The frame resumes when the last data has been confirmed written, but before the file handle
 /// is closed.
 /// Caller owns returned memory.
-pub async fn readFile(loop: *Loop, file_path: []const u8, max_size: usize) ![]u8 {
+pub fn readFile(loop: *Loop, file_path: []const u8, max_size: usize) ![]u8 {
     var close_op = try CloseOperation.start(loop);
     defer close_op.finish();
 
-    const fd = try await (async openRead(loop, file_path) catch unreachable);
+    const fd = try openRead(loop, file_path);
     close_op.setHandle(fd);
 
     var list = std.ArrayList(u8).init(loop.allocator);
@@ -660,7 +703,7 @@ pub async fn readFile(loop: *Loop, file_path: []const u8, max_size: usize) ![]u8
         try list.ensureCapacity(list.len + mem.page_size);
         const buf = list.items[list.len..];
         const buf_array = [_][]u8{buf};
-        const amt = try await (async preadv(loop, fd, buf_array, list.len) catch unreachable);
+        const amt = try preadv(loop, fd, buf_array, list.len);
         list.len += amt;
         if (list.len > max_size) {
             return error.FileTooBig;
@@ -1273,11 +1316,11 @@ const test_tmp_dir = "std_event_fs_test";
 //    return result;
 //}
 
-async fn testFsWatchCantFail(loop: *Loop, result: *(anyerror!void)) void {
+fn testFsWatchCantFail(loop: *Loop, result: *(anyerror!void)) void {
-    result.* = await (async testFsWatch(loop) catch unreachable);
+    result.* = testFsWatch(loop);
 }
 
-async fn testFsWatch(loop: *Loop) !void {
+fn testFsWatch(loop: *Loop) !void {
     const file_path = try std.fs.path.join(loop.allocator, [][]const u8{ test_tmp_dir, "file.txt" });
     defer loop.allocator.free(file_path);
 
@@ -1288,27 +1331,27 @@ async fn testFsWatch(loop: *Loop) !void {
     const line2_offset = 7;
 
     // first just write then read the file
-    try await try async writeFile(loop, file_path, contents);
+    try writeFile(loop, file_path, contents);
 
-    const read_contents = try await try async readFile(loop, file_path, 1024 * 1024);
+    const read_contents = try readFile(loop, file_path, 1024 * 1024);
     testing.expectEqualSlices(u8, contents, read_contents);
 
     // now watch the file
     var watch = try Watch(void).create(loop, 0);
     defer watch.destroy();
 
-    testing.expect((try await try async watch.addFile(file_path, {})) == null);
+    testing.expect((try watch.addFile(file_path, {})) == null);
 
-    const ev = try async watch.channel.get();
+    const ev = async watch.channel.get();
     var ev_consumed = false;
     defer if (!ev_consumed) await ev;
 
     // overwrite line 2
-    const fd = try await try async openReadWrite(loop, file_path, File.default_mode);
+    const fd = try await openReadWrite(loop, file_path, File.default_mode);
     {
         defer os.close(fd);
 
-        try await try async pwritev(loop, fd, []const []const u8{"lorem ipsum"}, line2_offset);
+        try pwritev(loop, fd, []const []const u8{"lorem ipsum"}, line2_offset);
     }
 
     ev_consumed = true;
@@ -1316,7 +1359,7 @@ async fn testFsWatch(loop: *Loop) !void {
         WatchEventId.CloseWrite => {},
         WatchEventId.Delete => @panic("wrong event"),
     }
-    const contents_updated = try await try async readFile(loop, file_path, 1024 * 1024);
+    const contents_updated = try readFile(loop, file_path, 1024 * 1024);
     testing.expectEqualSlices(u8,
         \\line 1
         \\lorem ipsum

std/event/future.zig

@@ -97,28 +97,27 @@ test "std.event.Future" {
     loop.run();
 }
 
-async fn testFuture(loop: *Loop) void {
+fn testFuture(loop: *Loop) void {
     var future = Future(i32).init(loop);
 
     var a = async waitOnFuture(&future);
     var b = async waitOnFuture(&future);
-    var c = async resolveFuture(&future);
+    resolveFuture(&future);
 
-    // TODO make this work:
+    // TODO https://github.com/ziglang/zig/issues/3077
     //const result = (await a) + (await b);
     const a_result = await a;
     const b_result = await b;
     const result = a_result + b_result;
 
-    await c;
     testing.expect(result == 12);
 }
 
-async fn waitOnFuture(future: *Future(i32)) i32 {
+fn waitOnFuture(future: *Future(i32)) i32 {
     return future.get().*;
 }
 
-async fn resolveFuture(future: *Future(i32)) void {
+fn resolveFuture(future: *Future(i32)) void {
     future.data = 6;
     future.resolve();
 }

std/event/loop.zig

@@ -89,12 +89,15 @@ pub const Loop = struct {
     pub const IoMode = enum {
         blocking,
         evented,
+        mixed,
     };
     pub const io_mode: IoMode = if (@hasDecl(root, "io_mode")) root.io_mode else IoMode.blocking;
     var global_instance_state: Loop = undefined;
+    threadlocal var per_thread_instance: ?*Loop = null;
     const default_instance: ?*Loop = switch (io_mode) {
         .blocking => null,
         .evented => &global_instance_state,
+        .mixed => per_thread_instance,
     };
     pub const instance: ?*Loop = if (@hasDecl(root, "event_loop")) root.event_loop else default_instance;
 
@@ -146,10 +149,12 @@ pub const Loop = struct {
                 .overlapped = ResumeNode.overlapped_init,
             },
         };
+        // We need at least one of these in case the fs thread wants to use onNextTick
         const extra_thread_count = thread_count - 1;
+        const resume_node_count = std.math.max(extra_thread_count, 1);
         self.eventfd_resume_nodes = try self.allocator.alloc(
             std.atomic.Stack(ResumeNode.EventFd).Node,
-            extra_thread_count,
+            resume_node_count,
         );
         errdefer self.allocator.free(self.eventfd_resume_nodes);
 
@@ -194,7 +199,7 @@ pub const Loop = struct {
                     eventfd_node.* = std.atomic.Stack(ResumeNode.EventFd).Node{
                         .data = ResumeNode.EventFd{
                             .base = ResumeNode{
-                                .id = ResumeNode.Id.EventFd,
+                                .id = .EventFd,
                                 .handle = undefined,
                                 .overlapped = ResumeNode.overlapped_init,
                             },
@@ -451,12 +456,12 @@ pub const Loop = struct {
         self.finishOneEvent();
     }
 
-    pub async fn linuxWaitFd(self: *Loop, fd: i32, flags: u32) !void {
+    pub fn linuxWaitFd(self: *Loop, fd: i32, flags: u32) !void {
         defer self.linuxRemoveFd(fd);
         suspend {
             var resume_node = ResumeNode.Basic{
                 .base = ResumeNode{
-                    .id = ResumeNode.Id.Basic,
+                    .id = .Basic,
                     .handle = @frame(),
                     .overlapped = ResumeNode.overlapped_init,
                 },
@@ -790,12 +795,15 @@ pub const Loop = struct {
 
     fn posixFsRun(self: *Loop) void {
         while (true) {
-            if (builtin.os == builtin.Os.linux) {
+            if (builtin.os == .linux) {
-                _ = @atomicRmw(i32, &self.os_data.fs_queue_item, AtomicRmwOp.Xchg, 0, AtomicOrder.SeqCst);
+                _ = @atomicRmw(i32, &self.os_data.fs_queue_item, .Xchg, 0, .SeqCst);
             }
             while (self.os_data.fs_queue.get()) |node| {
                 switch (node.data.msg) {
                     .End => return,
+                    .WriteV => |*msg| {
+                        msg.result = os.writev(msg.fd, msg.iov);
+                    },
                     .PWriteV => |*msg| {
                         msg.result = os.pwritev(msg.fd, msg.iov, msg.offset);
                     },
@@ -827,14 +835,14 @@ pub const Loop = struct {
                 self.finishOneEvent();
             }
             switch (builtin.os) {
-                builtin.Os.linux => {
+                .linux => {
                     const rc = os.linux.futex_wait(&self.os_data.fs_queue_item, os.linux.FUTEX_WAIT, 0, null);
                     switch (os.linux.getErrno(rc)) {
                         0, os.EINTR, os.EAGAIN => continue,
                         else => unreachable,
                     }
                 },
-                builtin.Os.macosx, builtin.Os.freebsd, builtin.Os.netbsd => {
+                .macosx, .freebsd, .netbsd => {
                     const fs_kevs = (*const [1]os.Kevent)(&self.os_data.fs_kevent_wait);
                     var out_kevs: [1]os.Kevent = undefined;
                     _ = os.kevent(self.os_data.fs_kqfd, fs_kevs, out_kevs[0..], null) catch unreachable;

std/fmt.zig

@@ -69,7 +69,6 @@ pub fn format(
         FormatFillAndAlign,
         FormatWidth,
         FormatPrecision,
-        Pointer,
     };
 
     comptime var start_index = 0;
@@ -109,9 +108,6 @@ pub fn format(
                     state = .Start;
                     start_index = i;
                 },
-                '*' => {
-                    state = .Pointer;
-                },
                 ':' => {
                     state = if (comptime peekIsAlign(fmt[i..])) State.FormatFillAndAlign else State.FormatWidth;
                     specifier_end = i;
@@ -256,19 +252,6 @@ pub fn format(
                     @compileError("Unexpected character in precision value: " ++ [_]u8{c});
                 },
             },
-            .Pointer => switch (c) {
-                '}' => {
-                    const arg_to_print = comptime nextArg(&used_pos_args, maybe_pos_arg, &next_arg);
-
-                    try output(context, @typeName(@typeOf(args[arg_to_print]).Child));
-                    try output(context, "@");
-                    try formatInt(@ptrToInt(args[arg_to_print]), 16, false, 0, context, Errors, output);
-
-                    state = .Start;
-                    start_index = i + 1;
-                },
-                else => @compileError("Unexpected format character after '*'"),
-            },
         }
     }
     comptime {
@@ -293,12 +276,19 @@ pub fn format(
 pub fn formatType(
     value: var,
     comptime fmt: []const u8,
-    comptime options: FormatOptions,
+    options: FormatOptions,
     context: var,
     comptime Errors: type,
     output: fn (@typeOf(context), []const u8) Errors!void,
     max_depth: usize,
 ) Errors!void {
+    if (comptime std.mem.eql(u8, fmt, "*")) {
+        try output(context, @typeName(@typeOf(value).Child));
+        try output(context, "@");
+        try formatInt(@ptrToInt(value), 16, false, FormatOptions{}, context, Errors, output);
+        return;
+    }
+
     const T = @typeOf(value);
     switch (@typeInfo(T)) {
         .ComptimeInt, .Int, .Float => {
@@ -438,15 +428,15 @@ pub fn formatType(
 fn formatValue(
     value: var,
     comptime fmt: []const u8,
-    comptime options: FormatOptions,
+    options: FormatOptions,
     context: var,
     comptime Errors: type,
     output: fn (@typeOf(context), []const u8) Errors!void,
 ) Errors!void {
     if (comptime std.mem.eql(u8, fmt, "B")) {
-        return formatBytes(value, options.width, 1000, context, Errors, output);
+        return formatBytes(value, options, 1000, context, Errors, output);
     } else if (comptime std.mem.eql(u8, fmt, "Bi")) {
-        return formatBytes(value, options.width, 1024, context, Errors, output);
+        return formatBytes(value, options, 1024, context, Errors, output);
     }
 
     const T = @typeOf(value);
@@ -460,7 +450,7 @@ fn formatValue(
 pub fn formatIntValue(
     value: var,
     comptime fmt: []const u8,
-    comptime options: FormatOptions,
+    options: FormatOptions,
     context: var,
     comptime Errors: type,
     output: fn (@typeOf(context), []const u8) Errors!void,
@@ -479,7 +469,7 @@ pub fn formatIntValue(
         uppercase = false;
     } else if (comptime std.mem.eql(u8, fmt, "c")) {
         if (@typeOf(int_value).bit_count <= 8) {
-            return formatAsciiChar(u8(int_value), context, Errors, output);
+            return formatAsciiChar(u8(int_value), options, context, Errors, output);
         } else {
             @compileError("Cannot print integer that is larger than 8 bits as a ascii");
         }
@@ -496,21 +486,21 @@ pub fn formatIntValue(
         @compileError("Unknown format string: '" ++ fmt ++ "'");
     }
 
-    return formatInt(int_value, radix, uppercase, options.width orelse 0, context, Errors, output);
+    return formatInt(int_value, radix, uppercase, options, context, Errors, output);
 }
 
 fn formatFloatValue(
     value: var,
     comptime fmt: []const u8,
-    comptime options: FormatOptions,
+    options: FormatOptions,
     context: var,
     comptime Errors: type,
     output: fn (@typeOf(context), []const u8) Errors!void,
 ) Errors!void {
     if (fmt.len == 0 or comptime std.mem.eql(u8, fmt, "e")) {
-        return formatFloatScientific(value, options.precision, context, Errors, output);
+        return formatFloatScientific(value, options, context, Errors, output);
     } else if (comptime std.mem.eql(u8, fmt, "d")) {
-        return formatFloatDecimal(value, options.precision, context, Errors, output);
+        return formatFloatDecimal(value, options, context, Errors, output);
     } else {
         @compileError("Unknown format string: '" ++ fmt ++ "'");
     }
@@ -519,7 +509,7 @@ fn formatFloatValue(
 pub fn formatText(
     bytes: []const u8,
     comptime fmt: []const u8,
-    comptime options: FormatOptions,
+    options: FormatOptions,
     context: var,
     comptime Errors: type,
     output: fn (@typeOf(context), []const u8) Errors!void,
@@ -527,11 +517,10 @@ pub fn formatText(
     if (fmt.len == 0) {
         return output(context, bytes);
     } else if (comptime std.mem.eql(u8, fmt, "s")) {
-        if (options.width) |w| return formatBuf(bytes, w, context, Errors, output);
+        return formatBuf(bytes, options, context, Errors, output);
-        return formatBuf(bytes, 0, context, Errors, output);
     } else if (comptime (std.mem.eql(u8, fmt, "x") or std.mem.eql(u8, fmt, "X"))) {
         for (bytes) |c| {
-            try formatInt(c, 16, fmt[0] == 'X', 2, context, Errors, output);
+            try formatInt(c, 16, fmt[0] == 'X', FormatOptions{ .width = 2, .fill = '0' }, context, Errors, output);
         }
         return;
     } else {
@@ -541,6 +530,7 @@ pub fn formatText(
 
 pub fn formatAsciiChar(
     c: u8,
+    options: FormatOptions,
     context: var,
     comptime Errors: type,
     output: fn (@typeOf(context), []const u8) Errors!void,
@@ -550,15 +540,16 @@ pub fn formatAsciiChar(
 
 pub fn formatBuf(
     buf: []const u8,
-    width: usize,
+    options: FormatOptions,
     context: var,
     comptime Errors: type,
     output: fn (@typeOf(context), []const u8) Errors!void,
 ) Errors!void {
     try output(context, buf);
 
+    const width = options.width orelse 0;
     var leftover_padding = if (width > buf.len) (width - buf.len) else return;
-    const pad_byte: u8 = ' ';
+    const pad_byte: u8 = options.fill;
     while (leftover_padding > 0) : (leftover_padding -= 1) {
         try output(context, (*const [1]u8)(&pad_byte)[0..1]);
     }
@@ -569,7 +560,7 @@ pub fn formatBuf(
 // same type unambiguously.
 pub fn formatFloatScientific(
     value: var,
-    maybe_precision: ?usize,
+    options: FormatOptions,
     context: var,
     comptime Errors: type,
     output: fn (@typeOf(context), []const u8) Errors!void,
@@ -591,7 +582,7 @@ pub fn formatFloatScientific(
     if (x == 0.0) {
         try output(context, "0");
 
-        if (maybe_precision) |precision| {
+        if (options.precision) |precision| {
             if (precision != 0) {
                 try output(context, ".");
                 var i: usize = 0;
@@ -610,7 +601,7 @@ pub fn formatFloatScientific(
     var buffer: [32]u8 = undefined;
     var float_decimal = errol.errol3(x, buffer[0..]);
 
-    if (maybe_precision) |precision| {
+    if (options.precision) |precision| {
         errol.roundToPrecision(&float_decimal, precision, errol.RoundMode.Scientific);
 
         try output(context, float_decimal.digits[0..1]);
@@ -650,13 +641,13 @@ pub fn formatFloatScientific(
         if (exp > -10 and exp < 10) {
             try output(context, "0");
         }
-        try formatInt(exp, 10, false, 0, context, Errors, output);
+        try formatInt(exp, 10, false, FormatOptions{ .width = 0 }, context, Errors, output);
     } else {
         try output(context, "-");
         if (exp > -10 and exp < 10) {
             try output(context, "0");
         }
-        try formatInt(-exp, 10, false, 0, context, Errors, output);
+        try formatInt(-exp, 10, false, FormatOptions{ .width = 0 }, context, Errors, output);
     }
 }
 
@@ -664,7 +655,7 @@ pub fn formatFloatScientific(
 // By default floats are printed at full precision (no rounding).
 pub fn formatFloatDecimal(
     value: var,
-    maybe_precision: ?usize,
+    options: FormatOptions,
     context: var,
     comptime Errors: type,
     output: fn (@typeOf(context), []const u8) Errors!void,
@@ -686,7 +677,7 @@ pub fn formatFloatDecimal(
     if (x == 0.0) {
         try output(context, "0");
 
-        if (maybe_precision) |precision| {
+        if (options.precision) |precision| {
             if (precision != 0) {
                 try output(context, ".");
                 var i: usize = 0;
@@ -707,7 +698,7 @@ pub fn formatFloatDecimal(
     var buffer: [32]u8 = undefined;
     var float_decimal = errol.errol3(x, buffer[0..]);
 
-    if (maybe_precision) |precision| {
+    if (options.precision) |precision| {
         errol.roundToPrecision(&float_decimal, precision, errol.RoundMode.Decimal);
 
         // exp < 0 means the leading is always 0 as errol result is normalized.
@@ -809,7 +800,7 @@ pub fn formatFloatDecimal(
 
 pub fn formatBytes(
     value: var,
-    width: ?usize,
+    options: FormatOptions,
     comptime radix: usize,
     context: var,
     comptime Errors: type,
@@ -833,7 +824,7 @@ pub fn formatBytes(
         else => unreachable,
     };
 
-    try formatFloatDecimal(new_value, width, context, Errors, output);
+    try formatFloatDecimal(new_value, options, context, Errors, output);
 
     if (suffix == ' ') {
         return output(context, "B");
@@ -851,7 +842,7 @@ pub fn formatInt(
     value: var,
     base: u8,
     uppercase: bool,
-    width: usize,
+    options: FormatOptions,
     context: var,
     comptime Errors: type,
     output: fn (@typeOf(context), []const u8) Errors!void,
@@ -863,9 +854,9 @@ pub fn formatInt(
         value;
 
     if (@typeOf(int_value).is_signed) {
-        return formatIntSigned(int_value, base, uppercase, width, context, Errors, output);
+        return formatIntSigned(int_value, base, uppercase, options, context, Errors, output);
     } else {
-        return formatIntUnsigned(int_value, base, uppercase, width, context, Errors, output);
+        return formatIntUnsigned(int_value, base, uppercase, options, context, Errors, output);
     }
 }
 
@@ -873,26 +864,30 @@ fn formatIntSigned(
     value: var,
     base: u8,
     uppercase: bool,
-    width: usize,
+    options: FormatOptions,
     context: var,
     comptime Errors: type,
     output: fn (@typeOf(context), []const u8) Errors!void,
 ) Errors!void {
+    const new_options = FormatOptions{
+        .width = if (options.width) |w| (if (w == 0) 0 else w - 1) else null,
+        .precision = options.precision,
+        .fill = options.fill,
+    };
+
     const uint = @IntType(false, @typeOf(value).bit_count);
     if (value < 0) {
         const minus_sign: u8 = '-';
         try output(context, (*const [1]u8)(&minus_sign)[0..]);
         const new_value = @intCast(uint, -(value + 1)) + 1;
-        const new_width = if (width == 0) 0 else (width - 1);
+        return formatIntUnsigned(new_value, base, uppercase, new_options, context, Errors, output);
-        return formatIntUnsigned(new_value, base, uppercase, new_width, context, Errors, output);
+    } else if (options.width == null or options.width.? == 0) {
-    } else if (width == 0) {
+        return formatIntUnsigned(@intCast(uint, value), base, uppercase, options, context, Errors, output);
-        return formatIntUnsigned(@intCast(uint, value), base, uppercase, width, context, Errors, output);
     } else {
         const plus_sign: u8 = '+';
         try output(context, (*const [1]u8)(&plus_sign)[0..]);
         const new_value = @intCast(uint, value);
-        const new_width = if (width == 0) 0 else (width - 1);
+        return formatIntUnsigned(new_value, base, uppercase, new_options, context, Errors, output);
-        return formatIntUnsigned(new_value, base, uppercase, new_width, context, Errors, output);
     }
 }
 
@@ -900,7 +895,7 @@ fn formatIntUnsigned(
     value: var,
     base: u8,
     uppercase: bool,
-    width: usize,
+    options: FormatOptions,
     context: var,
     comptime Errors: type,
     output: fn (@typeOf(context), []const u8) Errors!void,
@@ -921,31 +916,32 @@ fn formatIntUnsigned(
     }
 
     const digits_buf = buf[index..];
+    const width = options.width orelse 0;
     const padding = if (width > digits_buf.len) (width - digits_buf.len) else 0;
 
     if (padding > index) {
-        const zero_byte: u8 = '0';
+        const zero_byte: u8 = options.fill;
         var leftover_padding = padding - index;
         while (true) {
             try output(context, (*const [1]u8)(&zero_byte)[0..]);
             leftover_padding -= 1;
             if (leftover_padding == 0) break;
         }
-        mem.set(u8, buf[0..index], '0');
+        mem.set(u8, buf[0..index], options.fill);
         return output(context, buf);
     } else {
         const padded_buf = buf[index - padding ..];
-        mem.set(u8, padded_buf[0..padding], '0');
+        mem.set(u8, padded_buf[0..padding], options.fill);
         return output(context, padded_buf);
     }
 }
 
-pub fn formatIntBuf(out_buf: []u8, value: var, base: u8, uppercase: bool, width: usize) usize {
+pub fn formatIntBuf(out_buf: []u8, value: var, base: u8, uppercase: bool, options: FormatOptions) usize {
     var context = FormatIntBuf{
         .out_buf = out_buf,
         .index = 0,
     };
-    formatInt(value, base, uppercase, width, &context, error{}, formatIntCallback) catch unreachable;
+    formatInt(value, base, uppercase, options, &context, error{}, formatIntCallback) catch unreachable;
     return context.index;
 }
 const FormatIntBuf = struct {
@@ -1088,23 +1084,23 @@ fn countSize(size: *usize, bytes: []const u8) (error{}!void) {
 test "bufPrintInt" {
     var buffer: [100]u8 = undefined;
     const buf = buffer[0..];
-    testing.expect(mem.eql(u8, bufPrintIntToSlice(buf, i32(-12345678), 2, false, 0), "-101111000110000101001110"));
+    testing.expect(mem.eql(u8, bufPrintIntToSlice(buf, i32(-12345678), 2, false, FormatOptions{}), "-101111000110000101001110"));
-    testing.expect(mem.eql(u8, bufPrintIntToSlice(buf, i32(-12345678), 10, false, 0), "-12345678"));
+    testing.expect(mem.eql(u8, bufPrintIntToSlice(buf, i32(-12345678), 10, false, FormatOptions{}), "-12345678"));
-    testing.expect(mem.eql(u8, bufPrintIntToSlice(buf, i32(-12345678), 16, false, 0), "-bc614e"));
+    testing.expect(mem.eql(u8, bufPrintIntToSlice(buf, i32(-12345678), 16, false, FormatOptions{}), "-bc614e"));
-    testing.expect(mem.eql(u8, bufPrintIntToSlice(buf, i32(-12345678), 16, true, 0), "-BC614E"));
+    testing.expect(mem.eql(u8, bufPrintIntToSlice(buf, i32(-12345678), 16, true, FormatOptions{}), "-BC614E"));
 
-    testing.expect(mem.eql(u8, bufPrintIntToSlice(buf, u32(12345678), 10, true, 0), "12345678"));
+    testing.expect(mem.eql(u8, bufPrintIntToSlice(buf, u32(12345678), 10, true, FormatOptions{}), "12345678"));
 
-    testing.expect(mem.eql(u8, bufPrintIntToSlice(buf, u32(666), 10, false, 6), "000666"));
+    testing.expect(mem.eql(u8, bufPrintIntToSlice(buf, u32(666), 10, false, FormatOptions{ .width = 6 }), "   666"));
-    testing.expect(mem.eql(u8, bufPrintIntToSlice(buf, u32(0x1234), 16, false, 6), "001234"));
+    testing.expect(mem.eql(u8, bufPrintIntToSlice(buf, u32(0x1234), 16, false, FormatOptions{ .width = 6 }), "  1234"));
-    testing.expect(mem.eql(u8, bufPrintIntToSlice(buf, u32(0x1234), 16, false, 1), "1234"));
+    testing.expect(mem.eql(u8, bufPrintIntToSlice(buf, u32(0x1234), 16, false, FormatOptions{ .width = 1 }), "1234"));
 
-    testing.expect(mem.eql(u8, bufPrintIntToSlice(buf, i32(42), 10, false, 3), "+42"));
+    testing.expect(mem.eql(u8, bufPrintIntToSlice(buf, i32(42), 10, false, FormatOptions{ .width = 3 }), "+42"));
-    testing.expect(mem.eql(u8, bufPrintIntToSlice(buf, i32(-42), 10, false, 3), "-42"));
+    testing.expect(mem.eql(u8, bufPrintIntToSlice(buf, i32(-42), 10, false, FormatOptions{ .width = 3 }), "-42"));
 }
 
-fn bufPrintIntToSlice(buf: []u8, value: var, base: u8, uppercase: bool, width: usize) []u8 {
+fn bufPrintIntToSlice(buf: []u8, value: var, base: u8, uppercase: bool, options: FormatOptions) []u8 {
-    return buf[0..formatIntBuf(buf, value, base, uppercase, width)];
+    return buf[0..formatIntBuf(buf, value, base, uppercase, options)];
 }
 
 test "parse u64 digit too big" {
@@ -1162,7 +1158,8 @@ test "int.specifier" {
 }
 
 test "int.padded" {
-    try testFmt("u8: '0001'", "u8: '{:4}'", u8(1));
+    try testFmt("u8: '   1'", "u8: '{:4}'", u8(1));
+    try testFmt("u8: 'xxx1'", "u8: '{:x<4}'", u8(1));
 }
 
 test "buffer" {
@@ -1237,7 +1234,7 @@ test "cstr" {
 
 test "filesize" {
     try testFmt("file size: 63MiB\n", "file size: {Bi}\n", usize(63 * 1024 * 1024));
-    try testFmt("file size: 66.06MB\n", "file size: {B:2}\n", usize(63 * 1024 * 1024));
+    try testFmt("file size: 66.06MB\n", "file size: {B:.2}\n", usize(63 * 1024 * 1024));
 }
 
 test "struct" {
@@ -1342,7 +1339,7 @@ test "custom" {
         pub fn format(
             self: SelfType,
             comptime fmt: []const u8,
-            comptime options: FormatOptions,
+            options: FormatOptions,
             context: var,
             comptime Errors: type,
             output: fn (@typeOf(context), []const u8) Errors!void,
@@ -1548,7 +1545,7 @@ test "formatType max_depth" {
         pub fn format(
             self: SelfType,
             comptime fmt: []const u8,
-            comptime options: FormatOptions,
+            options: FormatOptions,
             context: var,
             comptime Errors: type,
             output: fn (@typeOf(context), []const u8) Errors!void,

std/fs.zig

@@ -442,6 +442,8 @@ pub fn deleteTree(allocator: *Allocator, full_path: []const u8) DeleteTreeError!
     }
 }
 
+/// TODO: separate this API into the one that opens directory handles to then subsequently open
+/// files, and into the one that reads files from an open directory handle.
 pub const Dir = struct {
     handle: Handle,
     allocator: *Allocator,
@@ -564,6 +566,17 @@ pub const Dir = struct {
         }
     }
 
+    pub fn openRead(self: Dir, file_path: []const u8) os.OpenError!File {
+        const path_c = try os.toPosixPath(file_path);
+        return self.openReadC(&path_c);
+    }
+
+    pub fn openReadC(self: Dir, file_path: [*]const u8) OpenError!File {
+        const flags = os.O_LARGEFILE | os.O_RDONLY;
+        const fd = try os.openatC(self.handle.fd, file_path, flags, 0);
+        return File.openHandle(fd);
+    }
+
     fn nextDarwin(self: *Dir) !?Entry {
         start_over: while (true) {
             if (self.handle.index >= self.handle.end_index) {

std/fs/file.zig

@@ -302,6 +302,14 @@ pub const File = struct {
         return os.write(self.handle, bytes);
     }
 
+    pub fn writev_iovec(self: File, iovecs: []const os.iovec_const) WriteError!void {
+        if (std.event.Loop.instance) |loop| {
+            return std.event.fs.writevPosix(loop, self.handle, iovecs);
+        } else {
+            return os.writev(self.handle, iovecs);
+        }
+    }
+
     pub fn inStream(file: File) InStream {
         return InStream{
             .file = file,

std/io.zig

@@ -146,7 +146,7 @@ pub fn InStream(comptime ReadError: type) type {
 
         /// Same as `readFull` but end of stream returns `error.EndOfStream`.
         pub fn readNoEof(self: *Self, buf: []u8) !void {
-            const amt_read = try self.read(buf);
+            const amt_read = try self.readFull(buf);
             if (amt_read < buf.len) return error.EndOfStream;
         }
 

std/math/big/int.zig

@@ -519,7 +519,7 @@ pub const Int = struct {
     pub fn format(
         self: Int,
         comptime fmt: []const u8,
-        comptime options: std.fmt.FormatOptions,
+        options: std.fmt.FormatOptions,
         context: var,
         comptime FmtError: type,
         output: fn (@typeOf(context), []const u8) FmtError!void,

std/net.zig

@@ -215,3 +215,33 @@ test "std.net.parseIp6" {
     assert(addr.addr[1] == 0x01);
     assert(addr.addr[2] == 0x00);
 }
+
+pub fn connectUnixSocket(path: []const u8) !std.fs.File {
+    const opt_non_block = if (std.event.Loop.instance != null) os.SOCK_NONBLOCK else 0;
+    const sockfd = try os.socket(
+        os.AF_UNIX,
+        os.SOCK_STREAM | os.SOCK_CLOEXEC | opt_non_block,
+        0,
+    );
+    errdefer os.close(sockfd);
+
+    var sock_addr = os.sockaddr{
+        .un = os.sockaddr_un{
+            .family = os.AF_UNIX,
+            .path = undefined,
+        },
+    };
+
+    if (path.len > @typeOf(sock_addr.un.path).len) return error.NameTooLong;
+    mem.copy(u8, sock_addr.un.path[0..], path);
+    const size = @intCast(u32, @sizeOf(os.sa_family_t) + path.len);
+    if (std.event.Loop.instance) |loop| {
+        try os.connect_async(sockfd, &sock_addr, size);
+        try loop.linuxWaitFd(sockfd, os.EPOLLIN | os.EPOLLOUT | os.EPOLLET);
+        try os.getsockoptError(sockfd);
+    } else {
+        try os.connect(sockfd, &sock_addr, size);
+    }
+
+    return std.fs.File.openHandle(sockfd);
+}

std/os.zig

@@ -99,19 +99,30 @@ pub const GetRandomError = OpenError;
 /// When linking against libc, this calls the
 /// appropriate OS-specific library call. Otherwise it uses the zig standard
 /// library implementation.
-pub fn getrandom(buf: []u8) GetRandomError!void {
+pub fn getrandom(buffer: []u8) GetRandomError!void {
     if (windows.is_the_target) {
-        return windows.RtlGenRandom(buf);
+        return windows.RtlGenRandom(buffer);
     }
-    if (linux.is_the_target) {
+    if (linux.is_the_target or freebsd.is_the_target) {
-        while (true) {
+        var buf = buffer;
-            const err = if (std.c.versionCheck(builtin.Version{ .major = 2, .minor = 25, .patch = 0 }).ok) blk: {
+        const use_c = !linux.is_the_target or
-                break :blk errno(std.c.getrandom(buf.ptr, buf.len, 0));
+            std.c.versionCheck(builtin.Version{ .major = 2, .minor = 25, .patch = 0 }).ok;
+
+        while (buf.len != 0) {
+            var err: u16 = undefined;
+
+            const num_read = if (use_c) blk: {
+                const rc = std.c.getrandom(buf.ptr, buf.len, 0);
+                err = std.c.getErrno(rc);
+                break :blk @bitCast(usize, rc);
             } else blk: {
-                break :blk linux.getErrno(linux.getrandom(buf.ptr, buf.len, 0));
+                const rc = linux.getrandom(buf.ptr, buf.len, 0);
+                err = linux.getErrno(rc);
+                break :blk rc;
             };
+
             switch (err) {
-                0 => return,
+                0 => buf = buf[num_read..],
                 EINVAL => unreachable,
                 EFAULT => unreachable,
                 EINTR => continue,
@@ -119,27 +130,15 @@ pub fn getrandom(buf: []u8) GetRandomError!void {
                 else => return unexpectedErrno(err),
             }
         }
-    }
+        return;
-    if (freebsd.is_the_target) {
-        while (true) {
-            const err = std.c.getErrno(std.c.getrandom(buf.ptr, buf.len, 0));
-
-            switch (err) {
-                0 => return,
-                EINVAL => unreachable,
-                EFAULT => unreachable,
-                EINTR => continue,
-                else => return unexpectedErrno(err),
-            }
-        }
     }
     if (wasi.is_the_target) {
-        switch (wasi.random_get(buf.ptr, buf.len)) {
+        switch (wasi.random_get(buffer.ptr, buffer.len)) {
             0 => return,
             else => |err| return unexpectedErrno(err),
         }
     }
-    return getRandomBytesDevURandom(buf);
+    return getRandomBytesDevURandom(buffer);
 }
 
 fn getRandomBytesDevURandom(buf: []u8) !void {
@@ -440,6 +439,33 @@ pub fn write(fd: fd_t, bytes: []const u8) WriteError!void {
 
 /// Write multiple buffers to a file descriptor. Keeps trying if it gets interrupted.
 /// This function is for blocking file descriptors only. For non-blocking, see
+/// `writevAsync`.
+pub fn writev(fd: fd_t, iov: []const iovec_const) WriteError!void {
+    while (true) {
+        // TODO handle the case when iov_len is too large and get rid of this @intCast
+        const rc = system.writev(fd, iov.ptr, @intCast(u32, iov.len));
+        switch (errno(rc)) {
+            0 => return,
+            EINTR => continue,
+            EINVAL => unreachable,
+            EFAULT => unreachable,
+            EAGAIN => unreachable, // This function is for blocking writes.
+            EBADF => unreachable, // Always a race condition.
+            EDESTADDRREQ => unreachable, // `connect` was never called.
+            EDQUOT => return error.DiskQuota,
+            EFBIG => return error.FileTooBig,
+            EIO => return error.InputOutput,
+            ENOSPC => return error.NoSpaceLeft,
+            EPERM => return error.AccessDenied,
+            EPIPE => return error.BrokenPipe,
+            else => |err| return unexpectedErrno(err),
+        }
+    }
+}
+
+/// Write multiple buffers to a file descriptor, with a position offset.
+/// Keeps trying if it gets interrupted.
+/// This function is for blocking file descriptors only. For non-blocking, see
 /// `pwritevAsync`.
 pub fn pwritev(fd: fd_t, iov: []const iovec_const, offset: u64) WriteError!void {
     if (darwin.is_the_target) {
@@ -524,7 +550,6 @@ pub const OpenError = error{
 };
 
 /// Open and possibly create a file. Keeps trying if it gets interrupted.
-/// `file_path` needs to be copied in memory to add a null terminating byte.
 /// See also `openC`.
 pub fn open(file_path: []const u8, flags: u32, perm: usize) OpenError!fd_t {
     const file_path_c = try toPosixPath(file_path);
@@ -564,6 +589,47 @@ pub fn openC(file_path: [*]const u8, flags: u32, perm: usize) OpenError!fd_t {
     }
 }
 
+/// Open and possibly create a file. Keeps trying if it gets interrupted.
+/// `file_path` is relative to the open directory handle `dir_fd`.
+/// See also `openatC`.
+pub fn openat(dir_fd: fd_t, file_path: []const u8, flags: u32, mode: usize) OpenError!fd_t {
+    const file_path_c = try toPosixPath(file_path);
+    return openatC(dir_fd, &file_path_c, flags, mode);
+}
+
+/// Open and possibly create a file. Keeps trying if it gets interrupted.
+/// `file_path` is relative to the open directory handle `dir_fd`.
+/// See also `openat`.
+pub fn openatC(dir_fd: fd_t, file_path: [*]const u8, flags: u32, mode: usize) OpenError!fd_t {
+    while (true) {
+        const rc = system.openat(dir_fd, file_path, flags, mode);
+        switch (errno(rc)) {
+            0 => return @intCast(fd_t, rc),
+            EINTR => continue,
+
+            EFAULT => unreachable,
+            EINVAL => unreachable,
+            EACCES => return error.AccessDenied,
+            EFBIG => return error.FileTooBig,
+            EOVERFLOW => return error.FileTooBig,
+            EISDIR => return error.IsDir,
+            ELOOP => return error.SymLinkLoop,
+            EMFILE => return error.ProcessFdQuotaExceeded,
+            ENAMETOOLONG => return error.NameTooLong,
+            ENFILE => return error.SystemFdQuotaExceeded,
+            ENODEV => return error.NoDevice,
+            ENOENT => return error.FileNotFound,
+            ENOMEM => return error.SystemResources,
+            ENOSPC => return error.NoSpaceLeft,
+            ENOTDIR => return error.NotDir,
+            EPERM => return error.AccessDenied,
+            EEXIST => return error.PathAlreadyExists,
+            EBUSY => return error.DeviceBusy,
+            else => |err| return unexpectedErrno(err),
+        }
+    }
+}
+
 pub fn dup2(old_fd: fd_t, new_fd: fd_t) !void {
     while (true) {
         switch (errno(system.dup2(old_fd, new_fd))) {
@@ -1655,7 +1721,7 @@ pub const ConnectError = error{
 /// For non-blocking, see `connect_async`.
 pub fn connect(sockfd: i32, sock_addr: *sockaddr, len: socklen_t) ConnectError!void {
     while (true) {
-        switch (errno(system.connect(sockfd, sock_addr, @sizeOf(sockaddr)))) {
+        switch (errno(system.connect(sockfd, sock_addr, len))) {
             0 => return,
             EACCES => return error.PermissionDenied,
             EPERM => return error.PermissionDenied,
@@ -1683,7 +1749,8 @@ pub fn connect(sockfd: i32, sock_addr: *sockaddr, len: socklen_t) ConnectError!v
 /// It expects to receive EINPROGRESS`.
 pub fn connect_async(sockfd: i32, sock_addr: *sockaddr, len: socklen_t) ConnectError!void {
     while (true) {
-        switch (errno(system.connect(sockfd, sock_addr, @sizeOf(sockaddr)))) {
+        switch (errno(system.connect(sockfd, sock_addr, len))) {
+            EINVAL => unreachable,
             EINTR => continue,
             0, EINPROGRESS => return,
             EACCES => return error.PermissionDenied,

std/os/bits/linux.zig

@@ -784,6 +784,7 @@ pub const socklen_t = u32;
 pub const sockaddr = extern union {
     in: sockaddr_in,
     in6: sockaddr_in6,
+    un: sockaddr_un,
 };
 
 pub const sockaddr_in = extern struct {

test/compare_output.zig

@@ -124,7 +124,7 @@ pub fn addCases(cases: *tests.CompareOutputContext) void {
         \\    const stdout = &(io.getStdOut() catch unreachable).outStream().stream;
         \\    stdout.print("Hello, world!\n{d:4} {x:3} {c}\n", u32(12), u16(0x12), u8('a')) catch unreachable;
         \\}
-    , "Hello, world!\n0012 012 a\n");
+    , "Hello, world!\n  12  12 a\n");
 
     cases.addC("number literals",
         \\const builtin = @import("builtin");

test/compile_errors.zig

@@ -2,6 +2,107 @@ const tests = @import("tests.zig");
 const builtin = @import("builtin");
 
 pub fn addCases(cases: *tests.CompileErrorContext) void {
+    cases.addCase(x: {
+        var tc = cases.create("variable in inline assembly template cannot be found",
+            \\export fn entry() void {
+            \\    var sp = asm volatile (
+            \\        "mov %[foo], sp"
+            \\        : [bar] "=r" (-> usize)
+            \\    );
+            \\}
+        , "tmp.zig:2:14: error: could not find 'foo' in the inputs or outputs.");
+        tc.target = tests.Target{
+            .Cross = tests.CrossTarget{
+                .arch = .x86_64,
+                .os = .linux,
+                .abi = .gnu,
+            },
+        };
+        break :x tc;
+    });
+
+    cases.add(
+        "indirect recursion of async functions detected",
+        \\var frame: ?anyframe = null;
+        \\
+        \\export fn a() void {
+        \\    _ = async rangeSum(10);
+        \\    while (frame) |f| resume f;
+        \\}
+        \\
+        \\fn rangeSum(x: i32) i32 {
+        \\    suspend {
+        \\        frame = @frame();
+        \\    }
+        \\    frame = null;
+        \\
+        \\    if (x == 0) return 0;
+        \\    var child = rangeSumIndirect(x - 1);
+        \\    return child + 1;
+        \\}
+        \\
+        \\fn rangeSumIndirect(x: i32) i32 {
+        \\    suspend {
+        \\        frame = @frame();
+        \\    }
+        \\    frame = null;
+        \\
+        \\    if (x == 0) return 0;
+        \\    var child = rangeSum(x - 1);
+        \\    return child + 1;
+        \\}
+    ,
+        "tmp.zig:8:1: error: '@Frame(rangeSum)' depends on itself",
+        "tmp.zig:15:33: note: when analyzing type '@Frame(rangeSumIndirect)' here",
+        "tmp.zig:26:25: note: when analyzing type '@Frame(rangeSum)' here",
+    );
+
+    cases.add(
+        "non-async function pointer eventually is inferred to become async",
+        \\export fn a() void {
+        \\    var non_async_fn: fn () void = undefined;
+        \\    non_async_fn = func;
+        \\}
+        \\fn func() void {
+        \\    suspend;
+        \\}
+    ,
+        "tmp.zig:5:1: error: 'func' cannot be async",
+        "tmp.zig:3:20: note: required to be non-async here",
+        "tmp.zig:6:5: note: suspends here",
+    );
+
+    cases.add(
+        "bad alignment in @asyncCall",
+        \\export fn entry() void {
+        \\    var ptr: async fn () void = func;
+        \\    var bytes: [64]u8 = undefined;
+        \\    _ = @asyncCall(&bytes, {}, ptr);
+        \\}
+        \\async fn func() void {}
+    ,
+        "tmp.zig:4:21: error: expected type '[]align(16) u8', found '*[64]u8'",
+    );
+
+    cases.add(
+        "atomic orderings of fence Acquire or stricter",
+        \\export fn entry() void {
+        \\    @fence(.Monotonic);
+        \\}
+    ,
+        "tmp.zig:2:12: error: atomic ordering must be Acquire or stricter",
+    );
+
+    cases.add(
+        "bad alignment in implicit cast from array pointer to slice",
+        \\export fn a() void {
+        \\    var x: [10]u8 = undefined;
+        \\    var y: []align(16) u8 = &x;
+        \\}
+    ,
+        "tmp.zig:3:30: error: expected type '[]align(16) u8', found '*[10]u8'",
+    );
+
     cases.add(
         "result location incompatibility mismatching handle_is_ptr (generic call)",
         \\export fn entry() void {
@@ -164,7 +265,7 @@ pub fn addCases(cases: *tests.CompileErrorContext) void {
         "non async function pointer passed to @asyncCall",
         \\export fn entry() void {
         \\    var ptr = afunc;
-        \\    var bytes: [100]u8 = undefined;
+        \\    var bytes: [100]u8 align(16) = undefined;
         \\    _ = @asyncCall(&bytes, {}, ptr);
         \\}
         \\fn afunc() void { }

test/runtime_safety.zig

@@ -30,7 +30,7 @@ pub fn addCases(cases: *tests.CompareOutputContext) void {
         \\    @import("std").os.exit(126);
         \\}
         \\pub fn main() void {
-        \\    var bytes: [1]u8 = undefined;
+        \\    var bytes: [1]u8 align(16) = undefined;
         \\    var ptr = other;
         \\    var frame = @asyncCall(&bytes, {}, ptr);
         \\}

test/stage1/behavior/array.zig

@@ -1,5 +1,6 @@
-const expect = @import("std").testing.expect;
+const std = @import("std");
-const mem = @import("std").mem;
+const expect = std.testing.expect;
+const mem = std.mem;
 
 test "arrays" {
     var array: [5]u32 = undefined;
@@ -274,3 +275,20 @@ test "double nested array to const slice cast in array literal" {
     S.entry(2);
     comptime S.entry(2);
 }
+
+test "read/write through global variable array of struct fields initialized via array mult" {
+    const S = struct {
+        fn doTheTest() void {
+            expect(storage[0].term == 1);
+            storage[0] = MyStruct{ .term = 123 };
+            expect(storage[0].term == 123);
+        }
+
+        pub const MyStruct = struct {
+            term: usize,
+        };
+
+        var storage: [1]MyStruct = [_]MyStruct{MyStruct{ .term = 1 }} ** 1;
+    };
+    S.doTheTest();
+}

test/stage1/behavior/async_fn.zig

@@ -280,7 +280,7 @@ test "async fn pointer in a struct field" {
         bar: async fn (*i32) void,
     };
     var foo = Foo{ .bar = simpleAsyncFn2 };
-    var bytes: [64]u8 = undefined;
+    var bytes: [64]u8 align(16) = undefined;
     const f = @asyncCall(&bytes, {}, foo.bar, &data);
     comptime expect(@typeOf(f) == anyframe->void);
     expect(data == 2);
@@ -317,7 +317,7 @@ test "@asyncCall with return type" {
         }
     };
     var foo = Foo{ .bar = Foo.middle };
-    var bytes: [150]u8 = undefined;
+    var bytes: [150]u8 align(16) = undefined;
     var aresult: i32 = 0;
     _ = @asyncCall(&bytes, &aresult, foo.bar);
     expect(aresult == 0);
@@ -817,3 +817,30 @@ test "struct parameter to async function is copied to the frame" {
     };
     S.doTheTest();
 }
+
+test "cast fn to async fn when it is inferred to be async" {
+    const S = struct {
+        var frame: anyframe = undefined;
+        var ok = false;
+
+        fn doTheTest() void {
+            var ptr: async fn () i32 = undefined;
+            ptr = func;
+            var buf: [100]u8 align(16) = undefined;
+            var result: i32 = undefined;
+            _ = await @asyncCall(&buf, &result, ptr);
+            expect(result == 1234);
+            ok = true;
+        }
+
+        fn func() i32 {
+            suspend {
+                frame = @frame();
+            }
+            return 1234;
+        }
+    };
+    _ = async S.doTheTest();
+    resume S.frame;
+    expect(S.ok);
+}

test/stage1/behavior/bitcast.zig

@@ -125,3 +125,17 @@ test "implicit cast to error union by returning" {
     S.entry();
     comptime S.entry();
 }
+
+// issue #3010: compiler segfault
+test "bitcast literal [4]u8 param to u32" {
+    const ip = @bitCast(u32, [_]u8{ 255, 255, 255, 255 });
+    expect(ip == maxInt(u32));
+}
+
+test "bitcast packed struct literal to byte" {
+    const Foo = packed struct {
+        value: u8,
+    };
+    const casted = @bitCast(u8, Foo{ .value = 0xF });
+    expect(casted == 0xf);
+}

test/stage1/behavior/enum_with_members.zig

@@ -8,8 +8,8 @@ const ET = union(enum) {
 
     pub fn print(a: *const ET, buf: []u8) anyerror!usize {
         return switch (a.*) {
-            ET.SINT => |x| fmt.formatIntBuf(buf, x, 10, false, 0),
+            ET.SINT => |x| fmt.formatIntBuf(buf, x, 10, false, fmt.FormatOptions{}),
-            ET.UINT => |x| fmt.formatIntBuf(buf, x, 10, false, 0),
+            ET.UINT => |x| fmt.formatIntBuf(buf, x, 10, false, fmt.FormatOptions{}),
         };
     }
 };

test/stage1/behavior/new_stack_call.zig

@@ -1,7 +1,7 @@
 const std = @import("std");
 const expect = std.testing.expect;
 
-var new_stack_bytes: [1024]u8 = undefined;
+var new_stack_bytes: [1024]u8 align(16) = undefined;
 
 test "calling a function with a new stack" {
     const arg = 1234;

test/stage1/behavior/void.zig

@@ -33,3 +33,8 @@ test "void optional" {
     var x: ?void = {};
     expect(x != null);
 }
+
+test "void array as a local variable initializer" {
+    var x = [_]void{{}} ** 1004;
+    var y = x[0];
+}

test/tests.zig

@@ -2,6 +2,8 @@ const std = @import("std");
 const debug = std.debug;
 const warn = debug.warn;
 const build = std.build;
+pub const Target = build.Target;
+pub const CrossTarget = build.CrossTarget;
 const Buffer = std.Buffer;
 const io = std.io;
 const fs = std.fs;
@@ -20,24 +22,18 @@ const runtime_safety = @import("runtime_safety.zig");
 const translate_c = @import("translate_c.zig");
 const gen_h = @import("gen_h.zig");
 
-const TestTarget = struct {
+const test_targets = [_]CrossTarget{
-    os: builtin.Os,
+    CrossTarget{
-    arch: builtin.Arch,
-    abi: builtin.Abi,
-};
-
-const test_targets = [_]TestTarget{
-    TestTarget{
         .os = .linux,
         .arch = .x86_64,
         .abi = .gnu,
     },
-    TestTarget{
+    CrossTarget{
         .os = .macosx,
         .arch = .x86_64,
         .abi = .gnu,
     },
-    TestTarget{
+    CrossTarget{
         .os = .windows,
         .arch = .x86_64,
         .abi = .msvc,
@@ -568,6 +564,7 @@ pub const CompileErrorContext = struct {
         link_libc: bool,
         is_exe: bool,
         is_test: bool,
+        target: Target = .Native,
 
         const SourceFile = struct {
             filename: []const u8,
@@ -655,6 +652,14 @@ pub const CompileErrorContext = struct {
             zig_args.append("--output-dir") catch unreachable;
             zig_args.append(b.pathFromRoot(b.cache_root)) catch unreachable;
 
+            switch (self.case.target) {
+                .Native => {},
+                .Cross => {
+                    try zig_args.append("-target");
+                    try zig_args.append(try self.case.target.zigTriple(b.allocator));
+                },
+            }
+
             switch (self.build_mode) {
                 Mode.Debug => {},
                 Mode.ReleaseSafe => zig_args.append("--release-safe") catch unreachable,