first class support for compiling C code

New CLI parameter: --c-source [options] [file]

It even works with `--cache on` when there are transitive dependencies.

Instead of `builder.addCExecutable`, use `builder.addExecutable` and pass
`null` for the root source file. Then use `builder.addCSourceFile`,
which takes the path to the C code, and a list of C compiler args.
Be sure to linkSystemLibrary("c") if you want libc headers to be
available.

Merge TestStep into LibExeObjStep. That was long overdue.

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");
-    exe.addCompileFlags([][]const u8{"-std=c99"});
-    exe.addSourceFile("test.c");
+    const exe = b.addExecutable("test", null);
+    exe.addCSourceFile("test.c",[][]const u8{"-std=c99"});
     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");
-    exe.addCompileFlags([][]const u8{"-std=c99"});
-    exe.addSourceFile("test.c");
+    const exe = b.addExecutable("test", null);
+    exe.addCSourceFile("test.c", [][]const u8{"-std=c99"});
     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
@@ -1788,6 +1793,7 @@ 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 +1811,7 @@ 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/codegen.cpp

@@ -7885,8 +7885,8 @@ 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) {
-                fprintf(stderr, "Unable to create %s: %s\n", buf_ptr(native_libc_txt), strerror(errno));
+            if ((err = os_rename(native_libc_tmp, native_libc_txt))) {
+                fprintf(stderr, "Unable to create %s: %s\n", buf_ptr(native_libc_txt), err_str(err));
                 exit(1);
             }
         }
@@ -8123,6 +8123,162 @@ 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) {
+        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) {
+        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);
+
+    // add the files depended on to the cache system
+    if (g->enable_cache) {
+        Buf *contents = buf_alloc();
+        if ((err = os_fetch_file_path(out_dep_path, contents, false))) {
+            fprintf(stderr, "unable to read .d file: %s\n", err_str(err));
+            exit(1);
+        }
+        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);
+        }
+        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(&g->cache_hash, filename_buf))) {
+                fprintf(stderr, "unable to add %s to cache: %s\n", buf_ptr(c_source_file), 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 +8793,13 @@ 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 +8951,7 @@ 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))) {
@@ -8805,16 +8969,25 @@ void codegen_build_and_link(CodeGen *g) {
         resolve_out_paths(g);
 
         codegen_add_time_event(g, "Code Generation");
-        do_code_gen(g);
-        codegen_add_time_event(g, "LLVM Emit Output");
-        zig_llvm_emit_output(g);
+        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);
 
-        if (g->out_h_path != nullptr) {
-            codegen_add_time_event(g, "Generate .h");
-            gen_h_file(g);
-        }
-        if (g->out_type != OutTypeObj && g->emit_file_type == EmitFileTypeBinary) {
-            codegen_link(g);
+            if (g->out_h_path != nullptr) {
+                codegen_add_time_event(g, "Generate .h");
+                gen_h_file(g);
+            }
+            if (g->out_type != OutTypeObj && g->emit_file_type == EmitFileTypeBinary) {
+                codegen_link(g);
+            }
         }
     }
 

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"
@@ -77,6 +77,7 @@ 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 +182,6 @@ enum Cmd {
     CmdNone,
     CmdBuild,
     CmdBuiltin,
-    CmdHelp,
     CmdRun,
     CmdTargets,
     CmdTest,
@@ -385,6 +385,7 @@ 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 +405,7 @@ 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 +514,7 @@ 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 +524,7 @@ 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 +590,9 @@ 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 +610,8 @@ 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) {
@@ -714,6 +719,19 @@ 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 +810,6 @@ 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 +851,6 @@ int main(int argc, char **argv) {
                     }
                     break;
                 case CmdBuiltin:
-                case CmdHelp:
                 case CmdVersion:
                 case CmdZen:
                 case CmdTargets:
@@ -910,15 +925,43 @@ int main(int argc, char **argv) {
     case CmdTranslateC:
     case CmdTest:
         {
-            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");
+            if (cmd == CmdBuild && !in_file && objects.length == 0 && asm_files.length == 0 &&
+                    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) {
-                fprintf(stderr, "When building an object file, --object arguments are invalid.\n");
-                return print_error_usage(arg0);
+            } else if (cmd == CmdBuild && out_type == OutTypeObj) {
+                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 +988,13 @@ 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 +1046,7 @@ 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;
 
@@ -1048,6 +1099,7 @@ int main(int argc, char **argv) {
             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 +1199,6 @@ 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 +1208,6 @@ int main(int argc, char **argv) {
     case CmdTargets:
         return print_target_list(stdout);
     case CmdNone:
-        fprintf(stderr, "Zig programming language\n");
-        return print_error_usage(arg0);
+        return print_full_usage(arg0, stderr, EXIT_FAILURE);
     }
 }

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/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);