Merge pull request #2005 from ziglang/c-source

first class support for compiling C code

example/mix_o_files/build.zig

@@ -3,10 +3,10 @@ const Builder = @import("std").build.Builder;
 pub fn build(b: *Builder) void {
     const obj = b.addObject("base64", "base64.zig");
 
-    const exe = b.addCExecutable("test");
+    const exe = b.addExecutable("test", null);
-    exe.addCompileFlags([][]const u8{"-std=c99"});
+    exe.addCSourceFile("test.c",[][]const u8{"-std=c99"});
-    exe.addSourceFile("test.c");
     exe.addObject(obj);
+    exe.linkSystemLibrary("c");
 
     b.default_step.dependOn(&exe.step);
 

example/shared_library/build.zig

@@ -3,10 +3,10 @@ const Builder = @import("std").build.Builder;
 pub fn build(b: *Builder) void {
     const lib = b.addSharedLibrary("mathtest", "mathtest.zig", b.version(1, 0, 0));
 
-    const exe = b.addCExecutable("test");
+    const exe = b.addExecutable("test", null);
-    exe.addCompileFlags([][]const u8{"-std=c99"});
+    exe.addCSourceFile("test.c", [][]const u8{"-std=c99"});
-    exe.addSourceFile("test.c");
     exe.linkLibrary(lib);
+    exe.linkSystemLibrary("c");
 
     b.default_step.dependOn(&exe.step);
 

src/all_types.hpp

@@ -1611,6 +1611,11 @@ enum ValgrindSupport {
     ValgrindSupportEnabled,
 };
 
+struct CFile {
+    ZigList<const char *> args;
+    const char *source_path;
+};
+
 // When adding fields, check if they should be added to the hash computation in build_with_cache
 struct CodeGen {
     //////////////////////////// Runtime State
@@ -1738,6 +1743,7 @@ struct CodeGen {
     Buf triple_str;
     Buf global_asm;
     Buf *out_h_path;
+    Buf *out_lib_path;
     Buf artifact_dir;
     Buf output_file_path;
     Buf o_file_output_path;
@@ -1788,6 +1794,7 @@ struct CodeGen {
     bool verbose_ir;
     bool verbose_llvm_ir;
     bool verbose_cimport;
+    bool verbose_cc;
     bool error_during_imports;
     bool generate_error_name_table;
     bool enable_cache;
@@ -1805,6 +1812,7 @@ struct CodeGen {
     ZigList<Buf *> forbidden_libs;
     ZigList<Buf *> link_objects;
     ZigList<Buf *> assembly_files;
+    ZigList<CFile *> c_source_files;
     ZigList<const char *> lib_dirs;
 
     ZigLibCInstallation *libc;

src/cache_hash.cpp

@@ -414,6 +414,39 @@ Error cache_add_file(CacheHash *ch, Buf *path) {
     return cache_add_file_fetch(ch, resolved_path, nullptr);
 }
 
+Error cache_add_dep_file(CacheHash *ch, Buf *dep_file_path, bool verbose) {
+    Error err;
+    Buf *contents = buf_alloc();
+    if ((err = os_fetch_file_path(dep_file_path, contents, false))) {
+        if (verbose) {
+            fprintf(stderr, "unable to read .d file: %s\n", err_str(err));
+        }
+        return ErrorReadingDepFile;
+    }
+    SplitIterator it = memSplit(buf_to_slice(contents), str("\n"));
+    // skip first line
+    SplitIterator_next(&it);
+    for (;;) {
+        Optional<Slice<uint8_t>> opt_line = SplitIterator_next(&it);
+        if (!opt_line.is_some)
+            break;
+        if (opt_line.value.len == 0)
+            continue;
+        SplitIterator line_it = memSplit(opt_line.value, str(" \t"));
+        Slice<uint8_t> filename;
+        if (!SplitIterator_next(&line_it).unwrap(&filename))
+            continue;
+        Buf *filename_buf = buf_create_from_slice(filename);
+        if ((err = cache_add_file(ch, filename_buf))) {
+            if (verbose) {
+                fprintf(stderr, "unable to add %s to cache: %s\n", buf_ptr(filename_buf), err_str(err));
+            }
+            return err;
+        }
+    }
+    return ErrorNone;
+}
+
 static Error write_manifest_file(CacheHash *ch) {
     Error err;
     Buf contents = BUF_INIT;
@@ -464,3 +497,4 @@ void cache_release(CacheHash *ch) {
 
     os_file_close(ch->manifest_file);
 }
+

src/cache_hash.hpp

@@ -56,6 +56,8 @@ Error ATTRIBUTE_MUST_USE cache_hit(CacheHash *ch, Buf *out_b64_digest);
 // If you did not get a cache hit, call this function for every file
 // that is depended on, and then finish with cache_final.
 Error ATTRIBUTE_MUST_USE cache_add_file(CacheHash *ch, Buf *path);
+// This opens a file created by -MD -MF args to Clang
+Error ATTRIBUTE_MUST_USE cache_add_dep_file(CacheHash *ch, Buf *path, bool verbose);
 
 // This variant of cache_add_file returns the file contents.
 // Also the file path argument must be already resolved.

src/codegen.cpp

@@ -175,6 +175,10 @@ void codegen_set_output_h_path(CodeGen *g, Buf *h_path) {
     g->out_h_path = h_path;
 }
 
+void codegen_set_output_lib_path(CodeGen *g, Buf *lib_path) {
+    g->out_lib_path = lib_path;
+}
+
 void codegen_set_output_path(CodeGen *g, Buf *path) {
     g->wanted_output_file_path = path;
 }
@@ -7885,8 +7889,8 @@ static void detect_libc(CodeGen *g) {
                 fprintf(stderr, "Unable to save %s: %s\n", buf_ptr(native_libc_tmp), strerror(errno));
                 exit(1);
             }
-            if (rename(buf_ptr(native_libc_tmp), buf_ptr(native_libc_txt)) == -1) {
+            if ((err = os_rename(native_libc_tmp, native_libc_txt))) {
-                fprintf(stderr, "Unable to create %s: %s\n", buf_ptr(native_libc_txt), strerror(errno));
+                fprintf(stderr, "Unable to create %s: %s\n", buf_ptr(native_libc_txt), err_str(err));
                 exit(1);
             }
         }
@@ -8123,6 +8127,143 @@ static void gen_global_asm(CodeGen *g) {
     }
 }
 
+static void gen_c_object(CodeGen *g, Buf *self_exe_path, CFile *c_file) {
+    Error err;
+
+    Buf *c_source_file = buf_create_from_str(c_file->source_path);
+    Buf *c_source_basename = buf_alloc();
+    os_path_split(c_source_file, nullptr, c_source_basename);
+    Buf *out_obj_name = buf_sprintf("%s%s", buf_ptr(c_source_basename), target_o_file_ext(g->zig_target));
+    Buf *out_obj_path = buf_alloc();
+    os_path_join(&g->cache_dir, out_obj_name, out_obj_path);
+    Buf *out_dep_name = buf_sprintf("%s.d", buf_ptr(c_source_file));
+    Buf *out_dep_path = buf_alloc();
+    os_path_join(&g->cache_dir, out_dep_name, out_dep_path);
+
+    Termination term;
+    ZigList<const char *> args = {};
+    args.append("cc");
+
+    if (g->enable_cache) {
+        args.append("-MD");
+        args.append("-MF");
+        args.append(buf_ptr(out_dep_path));
+    }
+
+    args.append("-isystem");
+    args.append(buf_ptr(g->zig_c_headers_dir));
+
+    if (g->libc != nullptr) {
+        args.append("-isystem");
+        args.append(buf_ptr(&g->libc->include_dir));
+    }
+
+    if (g->zig_target->is_native) {
+        args.append("-march=native");
+    } else {
+        args.append("-target");
+        args.append(buf_ptr(&g->triple_str));
+    }
+
+    if (!g->strip_debug_symbols) {
+        args.append("-g");
+    }
+    switch (g->build_mode) {
+        case BuildModeDebug:
+            if (g->libc_link_lib != nullptr) {
+                args.append("-fstack-protector-strong");
+                args.append("--param");
+                args.append("ssp-buffer-size=4");
+            } else {
+                args.append("-fno-stack-protector");
+            }
+            break;
+        case BuildModeSafeRelease:
+            args.append("-O2");
+            if (g->libc_link_lib != nullptr) {
+                args.append("-D_FORTIFY_SOURCE=2");
+                args.append("-fstack-protector-strong");
+                args.append("--param");
+                args.append("ssp-buffer-size=4");
+            } else {
+                args.append("-fno-stack-protector");
+            }
+            break;
+        case BuildModeFastRelease:
+            args.append("-O2");
+            args.append("-fno-stack-protector");
+            break;
+        case BuildModeSmallRelease:
+            args.append("-Os");
+            args.append("-fno-stack-protector");
+            break;
+    }
+
+    args.append("-o");
+    args.append(buf_ptr(out_obj_path));
+
+    args.append("-c");
+    args.append(buf_ptr(c_source_file));
+
+    if (!g->disable_pic && target_supports_fpic(g->zig_target)) {
+        args.append("-fPIC");
+    }
+
+    for (size_t arg_i = 0; arg_i < g->clang_argv_len; arg_i += 1) {
+        args.append(g->clang_argv[arg_i]);
+    }
+
+    for (size_t arg_i = 0; arg_i < c_file->args.length; arg_i += 1) {
+        args.append(c_file->args.at(arg_i));
+    }
+
+    if (g->verbose_cc) {
+        fprintf(stderr, "zig");
+        for (size_t arg_i = 0; arg_i < args.length; arg_i += 1) {
+            fprintf(stderr, " %s", args.at(arg_i));
+        }
+        fprintf(stderr, "\n");
+    }
+
+    os_spawn_process(buf_ptr(self_exe_path), args, &term);
+    if (term.how != TerminationIdClean || term.code != 0) {
+        fprintf(stderr, "`zig cc` failed\n");
+        exit(1);
+    }
+
+    g->link_objects.append(out_obj_path);
+
+    if (g->enable_cache) {
+        // add the files depended on to the cache system
+        if ((err = cache_add_file(&g->cache_hash, c_source_file))) {
+            fprintf(stderr, "unable to add %s to cache: %s\n", buf_ptr(c_source_file), err_str(err));
+            exit(1);
+        }
+        if ((err = cache_add_dep_file(&g->cache_hash, out_dep_path, true))) {
+            fprintf(stderr, "failed to add C source dependencies to cache: %s\n", err_str(err));
+            exit(1);
+        }
+    }
+}
+
+static void gen_c_objects(CodeGen *g) {
+    Error err;
+
+    if (g->c_source_files.length == 0)
+        return;
+
+    Buf *self_exe_path = buf_alloc();
+    if ((err = os_self_exe_path(self_exe_path))) {
+        fprintf(stderr, "Unable to get self exe path: %s\n", err_str(err));
+        exit(1);
+    }
+
+    for (size_t c_file_i = 0; c_file_i < g->c_source_files.length; c_file_i += 1) {
+        CFile *c_file = g->c_source_files.at(c_file_i);
+        gen_c_object(g, self_exe_path, c_file);
+    }
+}
+
 void codegen_add_object(CodeGen *g, Buf *object_path) {
     g->link_objects.append(object_path);
 }
@@ -8637,6 +8778,13 @@ static Error check_cache(CodeGen *g, Buf *manifest_dir, Buf *digest) {
     cache_list_of_buf(ch, g->forbidden_libs.items, g->forbidden_libs.length);
     cache_list_of_file(ch, g->link_objects.items, g->link_objects.length);
     cache_list_of_file(ch, g->assembly_files.items, g->assembly_files.length);
+    for (size_t c_file_i = 0; c_file_i < g->c_source_files.length; c_file_i += 1) {
+        CFile *c_file = g->c_source_files.at(c_file_i);
+        cache_file(ch, buf_create_from_str(c_file->source_path));
+        for (size_t opt_i = 0; opt_i < c_file->args.length; opt_i += 1) {
+            cache_buf(ch, buf_create_from_str(c_file->args.at(opt_i)));
+        }
+    }
     cache_int(ch, g->emit_file_type);
     cache_int(ch, g->build_mode);
     cache_int(ch, g->out_type);
@@ -8788,6 +8936,7 @@ void codegen_build_and_link(CodeGen *g) {
 
         gen_global_asm(g);
         gen_root_source(g);
+        gen_c_objects(g);
 
         if (g->enable_cache) {
             if ((err = cache_final(&g->cache_hash, &digest))) {
@@ -8805,6 +8954,14 @@ void codegen_build_and_link(CodeGen *g) {
         resolve_out_paths(g);
 
         codegen_add_time_event(g, "Code Generation");
+        if (g->out_type == OutTypeObj && g->c_source_files.length == 1) {
+            assert(g->link_objects.length == 1);
+            if ((err = os_rename(g->link_objects.pop(), &g->o_file_output_path))) {
+                fprintf(stderr, "unable to move object to '%s': %s\n",
+                        buf_ptr(&g->o_file_output_path), err_str(err));
+                exit(1);
+            }
+        } else {
             do_code_gen(g);
             codegen_add_time_event(g, "LLVM Emit Output");
             zig_llvm_emit_output(g);
@@ -8817,6 +8974,7 @@ void codegen_build_and_link(CodeGen *g) {
                 codegen_link(g);
             }
         }
+    }
 
     if (g->enable_cache) {
         cache_release(&g->cache_hash);

src/codegen.hpp

@@ -41,6 +41,7 @@ void codegen_set_test_filter(CodeGen *g, Buf *filter);
 void codegen_set_test_name_prefix(CodeGen *g, Buf *prefix);
 void codegen_set_lib_version(CodeGen *g, size_t major, size_t minor, size_t patch);
 void codegen_set_output_h_path(CodeGen *g, Buf *h_path);
+void codegen_set_output_lib_path(CodeGen *g, Buf *lib_path);
 void codegen_set_output_path(CodeGen *g, Buf *path);
 void codegen_add_time_event(CodeGen *g, const char *name);
 void codegen_print_timing_report(CodeGen *g, FILE *f);

src/error.cpp

@@ -36,6 +36,7 @@ const char *err_str(Error err) {
         case ErrorCacheUnavailable: return "cache unavailable";
         case ErrorPathTooLong: return "path too long";
         case ErrorCCompilerCannotFindFile: return "C compiler cannot find file";
+        case ErrorReadingDepFile: return "failed to read .d file";
     }
     return "(invalid error)";
 }

src/error.hpp

@@ -38,6 +38,7 @@ enum Error {
     ErrorCacheUnavailable,
     ErrorPathTooLong,
     ErrorCCompilerCannotFindFile,
+    ErrorReadingDepFile,
 };
 
 const char *err_str(Error err);

src/ir.cpp

@@ -18670,12 +18670,6 @@ static IrInstruction *ir_analyze_instruction_type_name(IrAnalyze *ira, IrInstruc
 }
 
 static IrInstruction *ir_analyze_instruction_c_import(IrAnalyze *ira, IrInstructionCImport *instruction) {
-    if (ira->codegen->enable_cache) {
-        ir_add_error(ira, &instruction->base,
-            buf_sprintf("TODO @cImport is incompatible with --cache on. The cache system currently is unable to detect subsequent changes in .h files."));
-        return ira->codegen->invalid_instruction;
-    }
-
     AstNode *node = instruction->base.source_node;
     assert(node->type == NodeTypeFnCallExpr);
     AstNode *block_node = node->data.fn_call_expr.params.at(0);

src/link.cpp

@@ -554,6 +554,7 @@ static void construct_linker_job_coff(LinkJob *lj) {
     bool is_library = g->out_type == OutTypeLib;
     switch (g->subsystem) {
         case TargetSubsystemAuto:
+            add_nt_link_args(lj, is_library);
             break;
         case TargetSubsystemConsole:
             lj->args.append("/SUBSYSTEM:console");

src/main.cpp

@@ -18,7 +18,7 @@
 #include <stdio.h>
 
 static int print_error_usage(const char *arg0) {
-    fprintf(stderr, "See `%s help` for detailed usage information\n", arg0);
+    fprintf(stderr, "See `%s --help` for detailed usage information\n", arg0);
     return EXIT_FAILURE;
 }
 
@@ -34,7 +34,6 @@ static int print_full_usage(const char *arg0, FILE *file, int return_code) {
         "  builtin                      show the source code of that @import(\"builtin\")\n"
         "  cc                           C compiler\n"
         "  fmt                          parse files and render in canonical zig format\n"
-        "  help                         show this usage information\n"
         "  id                           print the base64-encoded compiler id\n"
         "  init-exe                     initialize a `zig build` application in the cwd\n"
         "  init-lib                     initialize a `zig build` library in the cwd\n"
@@ -48,6 +47,7 @@ static int print_full_usage(const char *arg0, FILE *file, int return_code) {
         "\n"
         "Compile Options:\n"
         "  --assembly [source]          add assembly file to build\n"
+        "  --c-source [options] [file]  compile C source code\n"
         "  --cache-dir [path]           override the cache directory\n"
         "  --cache [auto|off|on]        build in global cache, print out paths to stdout\n"
         "  --color [auto|off|on]        enable or disable colored error messages\n"
@@ -60,6 +60,7 @@ static int print_full_usage(const char *arg0, FILE *file, int return_code) {
         "  --name [name]                override output name\n"
         "  --output [file]              override destination path\n"
         "  --output-h [file]            generate header file\n"
+        "  --output-lib [file]          override import library path\n"
         "  --pkg-begin [name] [path]    make pkg available to import and push current pkg\n"
         "  --pkg-end                    pop current pkg\n"
         "  --release-fast               build with optimizations on and safety off\n"
@@ -77,6 +78,7 @@ static int print_full_usage(const char *arg0, FILE *file, int return_code) {
         "  --verbose-ir                 enable compiler debug output for Zig IR\n"
         "  --verbose-llvm-ir            enable compiler debug output for LLVM IR\n"
         "  --verbose-cimport            enable compiler debug output for C imports\n"
+        "  --verbose-cc                 enable compiler debug output for C compilation\n"
         "  -dirafter [dir]              same as -isystem but do it last\n"
         "  -isystem [dir]               add additional search path for other .h files\n"
         "  -mllvm [arg]                 forward an arg to LLVM's option processing\n"
@@ -181,7 +183,6 @@ enum Cmd {
     CmdNone,
     CmdBuild,
     CmdBuiltin,
-    CmdHelp,
     CmdRun,
     CmdTargets,
     CmdTest,
@@ -375,6 +376,7 @@ int main(int argc, char **argv) {
     const char *in_file = nullptr;
     const char *out_file = nullptr;
     const char *out_file_h = nullptr;
+    const char *out_file_lib = nullptr;
     bool strip = false;
     bool is_static = false;
     OutType out_type = OutTypeUnknown;
@@ -385,6 +387,7 @@ int main(int argc, char **argv) {
     bool verbose_ir = false;
     bool verbose_llvm_ir = false;
     bool verbose_cimport = false;
+    bool verbose_cc = false;
     ErrColor color = ErrColorAuto;
     CacheOpt enable_cache = CacheOptAuto;
     const char *libc_txt = nullptr;
@@ -404,6 +407,7 @@ int main(int argc, char **argv) {
     ZigList<const char *> rpath_list = {0};
     bool each_lib_rpath = false;
     ZigList<const char *> objects = {0};
+    ZigList<CFile *> c_source_files = {0};
     ZigList<const char *> asm_files = {0};
     const char *test_filter = nullptr;
     const char *test_name_prefix = nullptr;
@@ -512,6 +516,7 @@ int main(int argc, char **argv) {
                         "  --verbose-ir           Enable compiler debug output for Zig IR\n"
                         "  --verbose-llvm-ir      Enable compiler debug output for LLVM IR\n"
                         "  --verbose-cimport      Enable compiler debug output for C imports\n"
+                        "  --verbose-cc           Enable compiler debug output for C compilation\n"
                         "\n"
                 , zig_exe_path);
                 return EXIT_SUCCESS;
@@ -521,7 +526,7 @@ int main(int argc, char **argv) {
                     "No 'build.zig' file found.\n"
                     "Initialize a 'build.zig' template file with `zig init-lib` or `zig init-exe`,\n"
                     "or build an executable directly with `zig build-exe $FILENAME.zig`.\n"
-                    "See: `zig build --help` or `zig help` for more options.\n"
+                    "See: `zig build --help` or `zig --help` for more options.\n"
                    );
             return EXIT_FAILURE;
         }
@@ -587,9 +592,9 @@ int main(int argc, char **argv) {
                 build_mode = BuildModeSmallRelease;
             } else if (strcmp(arg, "--help") == 0) {
                 if (cmd == CmdLibC) {
-                    return print_libc_usage(arg0, stderr, EXIT_FAILURE);
+                    return print_libc_usage(arg0, stdout, EXIT_SUCCESS);
                 } else {
-                    return print_full_usage(arg0, stderr, EXIT_FAILURE);
+                    return print_full_usage(arg0, stdout, EXIT_SUCCESS);
                 }
             } else if (strcmp(arg, "--strip") == 0) {
                 strip = true;
@@ -607,6 +612,8 @@ int main(int argc, char **argv) {
                 verbose_llvm_ir = true;
             } else if (strcmp(arg, "--verbose-cimport") == 0) {
                 verbose_cimport = true;
+            } else if (strcmp(arg, "--verbose-cc") == 0) {
+                verbose_cc = true;
             } else if (strcmp(arg, "-rdynamic") == 0) {
                 rdynamic = true;
             } else if (strcmp(arg, "--each-lib-rpath") == 0) {
@@ -656,6 +663,8 @@ int main(int argc, char **argv) {
                     out_file = argv[i];
                 } else if (strcmp(arg, "--output-h") == 0) {
                     out_file_h = argv[i];
+                } else if (strcmp(arg, "--output-lib") == 0) {
+                    out_file_lib = argv[i];
                 } else if (strcmp(arg, "--color") == 0) {
                     if (strcmp(argv[i], "auto") == 0) {
                         color = ErrColorAuto;
@@ -714,6 +723,19 @@ int main(int argc, char **argv) {
                     forbidden_link_libs.append(argv[i]);
                 } else if (strcmp(arg, "--object") == 0) {
                     objects.append(argv[i]);
+                } else if (strcmp(arg, "--c-source") == 0) {
+                    CFile *c_file = allocate<CFile>(1);
+                    for (;;) {
+                        if (argv[i][0] == '-') {
+                            c_file->args.append(argv[i]);
+                            i += 1;
+                            continue;
+                        } else {
+                            c_file->source_path = argv[i];
+                            c_source_files.append(c_file);
+                            break;
+                        }
+                    }
                 } else if (strcmp(arg, "--assembly") == 0) {
                     asm_files.append(argv[i]);
                 } else if (strcmp(arg, "--cache-dir") == 0) {
@@ -792,8 +814,6 @@ int main(int argc, char **argv) {
             } else if (strcmp(arg, "build-lib") == 0) {
                 cmd = CmdBuild;
                 out_type = OutTypeLib;
-            } else if (strcmp(arg, "help") == 0) {
-                cmd = CmdHelp;
             } else if (strcmp(arg, "run") == 0) {
                 cmd = CmdRun;
                 out_type = OutTypeExe;
@@ -835,7 +855,6 @@ int main(int argc, char **argv) {
                     }
                     break;
                 case CmdBuiltin:
-                case CmdHelp:
                 case CmdVersion:
                 case CmdZen:
                 case CmdTargets:
@@ -910,16 +929,44 @@ int main(int argc, char **argv) {
     case CmdTranslateC:
     case CmdTest:
         {
-            if (cmd == CmdBuild && !in_file && objects.length == 0 && asm_files.length == 0) {
+            if (cmd == CmdBuild && !in_file && objects.length == 0 && asm_files.length == 0 &&
-                fprintf(stderr, "Expected source file argument or at least one --object or --assembly argument.\n");
+                    c_source_files.length == 0)
+            {
+                fprintf(stderr,
+                    "Expected at least one of these things:\n"
+                    " * Zig root source file argument\n"
+                    " * --object argument\n"
+                    " * --assembly argument\n"
+                    " * --c-source argument\n");
                 return print_error_usage(arg0);
             } else if ((cmd == CmdTranslateC || cmd == CmdTest || cmd == CmdRun) && !in_file) {
                 fprintf(stderr, "Expected source file argument.\n");
                 return print_error_usage(arg0);
-            } else if (cmd == CmdBuild && out_type == OutTypeObj && objects.length != 0) {
+            } else if (cmd == CmdBuild && out_type == OutTypeObj) {
-                fprintf(stderr, "When building an object file, --object arguments are invalid.\n");
+                if (objects.length != 0) {
+                    fprintf(stderr,
+                        "When building an object file, --object arguments are invalid.\n"
+                        "Consider building a static library instead.\n");
                     return print_error_usage(arg0);
                 }
+                size_t zig_root_src_count = in_file ? 1 : 0;
+                if (zig_root_src_count + c_source_files.length > 1) {
+                    fprintf(stderr,
+                        "When building an object file, only one of these allowed:\n"
+                        " * Zig root source file argument\n"
+                        " * --c-source argument\n"
+                        "Consider building a static library instead.\n");
+                    return print_error_usage(arg0);
+                }
+                if (c_source_files.length != 0 && asm_files.length != 0) {
+                    fprintf(stderr,
+                        "When building an object file, only one of these allowed:\n"
+                        " * --assembly argument\n"
+                        " * --c-source argument\n"
+                        "Consider building a static library instead.\n");
+                    return print_error_usage(arg0);
+                }
+            }
 
             assert(cmd != CmdBuild || out_type != OutTypeUnknown);
 
@@ -945,6 +992,13 @@ int main(int argc, char **argv) {
                 }
             }
 
+            if (need_name && buf_out_name == nullptr && c_source_files.length == 1) {
+                Buf basename = BUF_INIT;
+                os_path_split(buf_create_from_str(c_source_files.at(0)->source_path), nullptr, &basename);
+                buf_out_name = buf_alloc();
+                os_path_extname(&basename, buf_out_name, nullptr);
+            }
+
             if (need_name && buf_out_name == nullptr) {
                 fprintf(stderr, "--name [name] not provided and unable to infer\n\n");
                 return print_error_usage(arg0);
@@ -996,6 +1050,7 @@ int main(int argc, char **argv) {
             g->verbose_ir = verbose_ir;
             g->verbose_llvm_ir = verbose_llvm_ir;
             g->verbose_cimport = verbose_cimport;
+            g->verbose_cc = verbose_cc;
             codegen_set_errmsg_color(g, color);
             g->system_linker_hack = system_linker_hack;
 
@@ -1043,11 +1098,14 @@ int main(int argc, char **argv) {
                 codegen_set_output_path(g, buf_create_from_str(out_file));
             if (out_file_h != nullptr && (out_type == OutTypeObj || out_type == OutTypeLib))
                 codegen_set_output_h_path(g, buf_create_from_str(out_file_h));
+            if (out_file_lib != nullptr && out_type == OutTypeLib && !is_static)
+                codegen_set_output_lib_path(g, buf_create_from_str(out_file_lib));
 
 
             add_package(g, cur_pkg, g->root_package);
 
             if (cmd == CmdBuild || cmd == CmdRun || cmd == CmdTest) {
+                g->c_source_files = c_source_files;
                 for (size_t i = 0; i < objects.length; i += 1) {
                     codegen_add_object(g, buf_create_from_str(objects.at(i)));
                 }
@@ -1147,8 +1205,6 @@ int main(int argc, char **argv) {
                 zig_unreachable();
             }
         }
-    case CmdHelp:
-        return print_full_usage(arg0, stdout, EXIT_SUCCESS);
     case CmdVersion:
         printf("%s\n", ZIG_VERSION_STRING);
         return EXIT_SUCCESS;
@@ -1158,7 +1214,6 @@ int main(int argc, char **argv) {
     case CmdTargets:
         return print_target_list(stdout);
     case CmdNone:
-        fprintf(stderr, "Zig programming language\n");
+        return print_full_usage(arg0, stderr, EXIT_FAILURE);
-        return print_error_usage(arg0);
     }
 }

src/os.cpp

@@ -1232,6 +1232,18 @@ static Error os_buf_to_tmp_file_posix(Buf *contents, Buf *suffix, Buf *out_tmp_p
 }
 #endif
 
+Buf *os_tmp_filename(Buf *prefix, Buf *suffix) {
+    Buf *result = buf_create_from_buf(prefix);
+
+    const char base64[] = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_";
+    assert(array_length(base64) == 64 + 1);
+    for (size_t i = 0; i < 12; i += 1) {
+        buf_append_char(result, base64[rand() % 64]);
+    }
+    buf_append_buf(result, suffix);
+    return result;
+}
+
 #if defined(ZIG_OS_WINDOWS)
 static Error os_buf_to_tmp_file_windows(Buf *contents, Buf *suffix, Buf *out_tmp_path) {
     char tmp_dir[MAX_PATH + 1];

src/os.hpp

@@ -121,6 +121,7 @@ Error ATTRIBUTE_MUST_USE os_get_cwd(Buf *out_cwd);
 bool os_stderr_tty(void);
 void os_stderr_set_color(TermColor color);
 
+Buf *os_tmp_filename(Buf *prefix, Buf *suffix);
 Error os_buf_to_tmp_file(Buf *contents, Buf *suffix, Buf *out_tmp_path);
 Error os_delete_file(Buf *path);
 

src/target.cpp

@@ -1049,3 +1049,9 @@ bool target_requires_libc(const ZigTarget *target) {
     // since this is the stable syscall interface.
     return (target_is_darwin(target) || target->os == OsFreeBSD || target->os == OsNetBSD);
 }
+
+bool target_supports_fpic(const ZigTarget *target) {
+  // This is not whether the target supports Position Independent Code, but whether the -fPIC
+  // C compiler argument is valid.
+  return target->os != OsWindows;
+}

src/target.hpp

@@ -141,5 +141,6 @@ bool target_allows_addr_zero(const ZigTarget *target);
 bool target_has_valgrind_support(const ZigTarget *target);
 bool target_is_darwin(const ZigTarget *target);
 bool target_requires_libc(const ZigTarget *target);
+bool target_supports_fpic(const ZigTarget *target);
 
 #endif

src/translate_c.cpp

@@ -4776,6 +4776,15 @@ Error parse_h_file(ImportTableEntry *import, ZigList<ErrorMsg *> *errors, const
     clang_argv.append("-x");
     clang_argv.append("c");
 
+    Buf *out_dep_path = nullptr;
+    if (codegen->enable_cache) {
+        Buf *prefix = buf_sprintf("%s" OS_SEP, buf_ptr(&codegen->cache_dir));
+        out_dep_path = os_tmp_filename(prefix, buf_create_from_str(".d"));
+        clang_argv.append("-MD");
+        clang_argv.append("-MF");
+        clang_argv.append(buf_ptr(out_dep_path));
+    }
+
     if (c->codegen->zig_target->is_native) {
         char *ZIG_PARSEC_CFLAGS = getenv("ZIG_NATIVE_PARSEC_CFLAGS");
         if (ZIG_PARSEC_CFLAGS) {
@@ -4912,6 +4921,17 @@ Error parse_h_file(ImportTableEntry *import, ZigList<ErrorMsg *> *errors, const
         return ErrorCCompileErrors;
     }
 
+    if (codegen->enable_cache) {
+        Error err;
+        assert(out_dep_path != nullptr);
+        if ((err = cache_add_dep_file(&codegen->cache_hash, out_dep_path, codegen->verbose_cimport))) {
+            if (codegen->verbose_cimport) {
+                fprintf(stderr, "translate-c: aborting due to failed cache operation: %s\n", err_str(err));
+            }
+            return err;
+        }
+    }
+
     c->ctx = ZigClangASTUnit_getASTContext(ast_unit);
     c->source_manager = ZigClangASTUnit_getSourceManager(ast_unit);
     c->root = trans_create_node(c, NodeTypeContainerDecl);

std/buf_set.zig

@@ -32,6 +32,10 @@ pub const BufSet = struct {
         }
     }
 
+    pub fn exists(self: BufSet, key: []const u8) bool {
+        return self.hash_map.get(key) != null;
+    }
+
     pub fn delete(self: *BufSet, key: []const u8) void {
         const entry = self.hash_map.remove(key) orelse return;
         self.free(entry.key);

test/build_examples.zig

@@ -7,12 +7,8 @@ pub fn addCases(cases: *tests.BuildExamplesContext) void {
     cases.addC("example/hello_world/hello_libc.zig");
     cases.add("example/cat/main.zig");
     cases.add("example/guess_number/main.zig");
-    if (!is_windows) {
-        // TODO get this test passing on windows
-        // See https://github.com/ziglang/zig/issues/538
     cases.addBuildFile("example/shared_library/build.zig");
     cases.addBuildFile("example/mix_o_files/build.zig");
-    }
     if (builtin.os != builtin.Os.macosx) {
         // TODO https://github.com/ziglang/zig/issues/1126
         cases.addBuildFile("test/standalone/issue_339/build.zig");

test/stage1/c_abi/build.zig

@@ -3,9 +3,10 @@ const Builder = @import("std").build.Builder;
 pub fn build(b: *Builder) void {
     const rel_opts = b.standardReleaseOptions();
 
-    const c_obj = b.addCObject("cfuncs", "cfuncs.c");
+    const c_obj = b.addObject("cfuncs", null);
+    c_obj.addCSourceFile("cfuncs.c", [][]const u8{"-std=c99"});
     c_obj.setBuildMode(rel_opts);
-    c_obj.setNoStdLib(true);
+    c_obj.linkSystemLibrary("c");
 
     const main = b.addTest("main.zig");
     main.setBuildMode(rel_opts);