implement coroutine resume

doc/langref.html.in

@@ -5682,7 +5682,7 @@ ErrorSetExpr = (PrefixOpExpression "!" PrefixOpExpression) | PrefixOpExpression
 
 BlockOrExpression = Block | Expression
 
-Expression = TryExpression | ReturnExpression | BreakExpression | AssignmentExpression | CancelExpression
+Expression = TryExpression | ReturnExpression | BreakExpression | AssignmentExpression | CancelExpression | ResumeExpression
 
 AsmExpression = "asm" option("volatile") "(" String option(AsmOutput) ")"
 
@@ -5730,6 +5730,8 @@ BreakExpression = "break" option(":" Symbol) option(Expression)
 
 CancelExpression = "cancel" Expression;
 
+ResumeExpression = "resume" Expression;
+
 Defer(body) = ("defer" | "deferror") body
 
 IfExpression(body) = "if" "(" Expression ")" body option("else" BlockExpression(body))

src/all_types.hpp

@@ -403,6 +403,7 @@ enum NodeType {
     NodeTypeTestExpr,
     NodeTypeErrorSetDecl,
     NodeTypeCancel,
+    NodeTypeResume,
     NodeTypeAwaitExpr,
     NodeTypeSuspend,
 };
@@ -849,6 +850,10 @@ struct AstNodeCancelExpr {
     AstNode *expr;
 };
 
+struct AstNodeResumeExpr {
+    AstNode *expr;
+};
+
 struct AstNodeContinueExpr {
     Buf *name;
 };
@@ -930,6 +935,7 @@ struct AstNode {
         AstNodeVarLiteral var_literal;
         AstNodeErrorSetDecl err_set_decl;
         AstNodeCancelExpr cancel_expr;
+        AstNodeResumeExpr resume_expr;
         AstNodeAwaitExpr await_expr;
         AstNodeSuspend suspend;
     } data;

src/analyze.cpp

@@ -3212,6 +3212,7 @@ void scan_decls(CodeGen *g, ScopeDecls *decls_scope, AstNode *node) {
         case NodeTypeTestExpr:
         case NodeTypeErrorSetDecl:
         case NodeTypeCancel:
+        case NodeTypeResume:
         case NodeTypeAwaitExpr:
         case NodeTypeSuspend:
             zig_unreachable();

src/ast_render.cpp

@@ -246,6 +246,8 @@ static const char *node_type_str(NodeType node_type) {
             return "ErrorSetDecl";
         case NodeTypeCancel:
             return "Cancel";
+        case NodeTypeResume:
+            return "Resume";
         case NodeTypeAwaitExpr:
             return "AwaitExpr";
         case NodeTypeSuspend:
@@ -1049,6 +1051,12 @@ static void render_node_extra(AstRender *ar, AstNode *node, bool grouped) {
                 render_node_grouped(ar, node->data.cancel_expr.expr);
                 break;
             }
+        case NodeTypeResume:
+            {
+                fprintf(ar->f, "resume ");
+                render_node_grouped(ar, node->data.resume_expr.expr);
+                break;
+            }
         case NodeTypeAwaitExpr:
             {
                 fprintf(ar->f, "await ");

src/codegen.cpp

@@ -4004,7 +4004,7 @@ static LLVMValueRef ir_render_coro_save(CodeGen *g, IrExecutable *executable, Ir
 
 static LLVMValueRef get_coro_alloc_helper_fn_val(CodeGen *g, LLVMTypeRef alloc_fn_type_ref, TypeTableEntry *fn_type) {
     if (g->coro_alloc_helper_fn_val != nullptr)
-        return g->coro_alloc_fn_val;
+        return g->coro_alloc_helper_fn_val;
 
     assert(fn_type->id == TypeTableEntryIdFn);
 

src/ir.cpp

@@ -5927,6 +5927,16 @@ static IrInstruction *ir_gen_cancel(IrBuilder *irb, Scope *parent_scope, AstNode
     return ir_build_cancel(irb, parent_scope, node, target_inst);
 }
 
+static IrInstruction *ir_gen_resume(IrBuilder *irb, Scope *parent_scope, AstNode *node) {
+    assert(node->type == NodeTypeResume);
+
+    IrInstruction *target_inst = ir_gen_node(irb, node->data.resume_expr.expr, parent_scope);
+    if (target_inst == irb->codegen->invalid_instruction)
+        return irb->codegen->invalid_instruction;
+
+    return ir_build_coro_resume(irb, parent_scope, node, target_inst);
+}
+
 static IrInstruction *ir_gen_await_expr(IrBuilder *irb, Scope *parent_scope, AstNode *node) {
     assert(node->type == NodeTypeAwaitExpr);
 
@@ -6101,6 +6111,8 @@ static IrInstruction *ir_gen_node_raw(IrBuilder *irb, AstNode *node, Scope *scop
             return ir_lval_wrap(irb, scope, ir_gen_err_set_decl(irb, scope, node), lval);
         case NodeTypeCancel:
             return ir_lval_wrap(irb, scope, ir_gen_cancel(irb, scope, node), lval);
+        case NodeTypeResume:
+            return ir_lval_wrap(irb, scope, ir_gen_resume(irb, scope, node), lval);
         case NodeTypeAwaitExpr:
             return ir_lval_wrap(irb, scope, ir_gen_await_expr(irb, scope, node), lval);
         case NodeTypeSuspend:
@@ -17364,8 +17376,12 @@ static TypeTableEntry *ir_analyze_instruction_coro_resume(IrAnalyze *ira, IrInst
     if (type_is_invalid(awaiter_handle->value.type))
         return ira->codegen->builtin_types.entry_invalid;
 
+    IrInstruction *casted_target = ir_implicit_cast(ira, awaiter_handle, ira->codegen->builtin_types.entry_promise);
+    if (type_is_invalid(casted_target->value.type))
+        return ira->codegen->builtin_types.entry_invalid;
+
     IrInstruction *result = ir_build_coro_resume(&ira->new_irb, instruction->base.scope,
-            instruction->base.source_node, awaiter_handle);
+            instruction->base.source_node, casted_target);
     ir_link_new_instruction(result, &instruction->base);
     result->value.type = ira->codegen->builtin_types.entry_void;
     return result->value.type;

src/parser.cpp

@@ -1638,6 +1638,24 @@ static AstNode *ast_parse_cancel_expr(ParseContext *pc, size_t *token_index) {
     return node;
 }
 
+/*
+ResumeExpression = "resume" Expression;
+*/
+static AstNode *ast_parse_resume_expr(ParseContext *pc, size_t *token_index) {
+    Token *token = &pc->tokens->at(*token_index);
+
+    if (token->id != TokenIdKeywordResume) {
+        return nullptr;
+    }
+    *token_index += 1;
+
+    AstNode *node = ast_create_node(pc, NodeTypeResume, token);
+
+    node->data.resume_expr.expr = ast_parse_expression(pc, token_index, false);
+
+    return node;
+}
+
 /*
 Defer(body) = ("defer" | "errdefer") body
 */
@@ -2266,7 +2284,7 @@ static AstNode *ast_parse_block_or_expression(ParseContext *pc, size_t *token_in
 }
 
 /*
-Expression = TryExpression | ReturnExpression | BreakExpression | AssignmentExpression | CancelExpression
+Expression = TryExpression | ReturnExpression | BreakExpression | AssignmentExpression | CancelExpression | ResumeExpression
 */
 static AstNode *ast_parse_expression(ParseContext *pc, size_t *token_index, bool mandatory) {
     Token *token = &pc->tokens->at(*token_index);
@@ -2287,6 +2305,10 @@ static AstNode *ast_parse_expression(ParseContext *pc, size_t *token_index, bool
     if (cancel_expr)
         return cancel_expr;
 
+    AstNode *resume_expr = ast_parse_resume_expr(pc, token_index);
+    if (resume_expr)
+        return resume_expr;
+
     AstNode *ass_expr = ast_parse_ass_expr(pc, token_index, false);
     if (ass_expr)
         return ass_expr;
@@ -3060,6 +3082,9 @@ void ast_visit_node_children(AstNode *node, void (*visit)(AstNode **, void *cont
         case NodeTypeCancel:
             visit_field(&node->data.cancel_expr.expr, visit, context);
             break;
+        case NodeTypeResume:
+            visit_field(&node->data.resume_expr.expr, visit, context);
+            break;
         case NodeTypeAwaitExpr:
             visit_field(&node->data.await_expr.expr, visit, context);
             break;

test/cases/coroutines.zig

@@ -14,3 +14,30 @@ async fn simpleAsyncFn() void {
     suspend;
     x += 1;
 }
+
+test "coroutine suspend, resume, cancel" {
+    seq('a');
+    const p = (async(std.debug.global_allocator) testAsyncSeq()) catch unreachable;
+    seq('c');
+    resume p;
+    seq('f');
+    cancel p;
+    seq('g');
+
+    assert(std.mem.eql(u8, points, "abcdefg"));
+}
+
+async fn testAsyncSeq() void {
+    defer seq('e');
+
+    seq('b');
+    suspend;
+    seq('d');
+}
+var points = []u8{0} ** "abcdefg".len;
+var index: usize = 0;
+
+fn seq(c: u8) void {
+    points[index] = c;
+    index += 1;
+}