std.Build: add an option to addCSourceFiles() to include a precompiled header

xxxbxxx · xxxbxxx · commit ed01db0f1b3d · 2024-07-24T15:20:57.000+02:00
diff --git a/lib/std/Build/Module.zig b/lib/std/Build/Module.zig
@@ -153,18 +153,21 @@ pub const CSourceFiles = struct {
     files: []const []const u8,
     lang: ?CSourceLang = null,
     flags: []const []const u8,
+    precompiled_header: ?LazyPath = null,
 };
 
 pub const CSourceFile = struct {
     file: LazyPath,
     lang: ?CSourceLang = null,
     flags: []const []const u8 = &.{},
+    precompiled_header: ?LazyPath = null,
 
     pub fn dupe(file: CSourceFile, b: *std.Build) CSourceFile {
         return .{
             .file = file.file.dupe(b),
             .lang = file.lang,
             .flags = b.dupeStrings(file.flags),
+            .precompiled_header = file.precompiled_header,
         };
     }
 };
@@ -557,6 +560,7 @@ pub const AddCSourceFilesOptions = struct {
     files: []const []const u8,
     lang: ?CSourceLang = null,
     flags: []const []const u8 = &.{},
+    precompiled_header: ?LazyPath = null,
 };
 
 /// Handy when you have many C/C++ source files and want them all to have the same flags.
@@ -579,9 +583,14 @@ pub fn addCSourceFiles(m: *Module, options: AddCSourceFilesOptions) void {
         .files = b.dupeStrings(options.files),
         .lang = options.lang,
         .flags = b.dupeStrings(options.flags),
+        .precompiled_header = options.precompiled_header,
     };
     m.link_objects.append(allocator, .{ .c_source_files = c_source_files }) catch @panic("OOM");
     addLazyPathDependenciesOnly(m, c_source_files.root);
+
+    if (options.precompiled_header) |pch| {
+        addLazyPathDependenciesOnly(m, pch);
+    }
 }
 
 pub fn addCSourceFile(m: *Module, source: CSourceFile) void {
@@ -591,6 +600,10 @@ pub fn addCSourceFile(m: *Module, source: CSourceFile) void {
     c_source_file.* = source.dupe(b);
     m.link_objects.append(allocator, .{ .c_source_file = c_source_file }) catch @panic("OOM");
     addLazyPathDependenciesOnly(m, source.file);
+
+    if (source.precompiled_header) |pch| {
+        addLazyPathDependenciesOnly(m, pch);
+    }
 }
 
 /// Resource files must have the extension `.rc`.
diff --git a/lib/std/Build/Step/Compile.zig b/lib/std/Build/Step/Compile.zig
@@ -1272,7 +1272,7 @@ fn getZigArgs(compile: *Compile) ![][]const u8 {
                     .c_source_file => |c_source_file| l: {
                         if (!my_responsibility) break :l;
 
-                        if (c_source_file.flags.len == 0) {
+                        if (c_source_file.flags.len == 0 and c_source_file.precompiled_header == null) {
                             if (prev_has_cflags) {
                                 try zig_args.append("-cflags");
                                 try zig_args.append("--");
@@ -1283,6 +1283,11 @@ fn getZigArgs(compile: *Compile) ![][]const u8 {
                             for (c_source_file.flags) |arg| {
                                 try zig_args.append(arg);
                             }
+                            if (c_source_file.precompiled_header) |pch| {
+                                try zig_args.append("-include-pch");
+                                try zig_args.append(pch.getPath(b));
+                                try zig_args.append("-fpch-validate-input-files-content");
+                            }
                             try zig_args.append("--");
                             prev_has_cflags = true;
                         }
@@ -1304,7 +1309,7 @@ fn getZigArgs(compile: *Compile) ![][]const u8 {
                     .c_source_files => |c_source_files| l: {
                         if (!my_responsibility) break :l;
 
-                        if (c_source_files.flags.len == 0) {
+                        if (c_source_files.flags.len == 0 and c_source_files.precompiled_header == null) {
                             if (prev_has_cflags) {
                                 try zig_args.append("-cflags");
                                 try zig_args.append("--");
@@ -1315,6 +1320,13 @@ fn getZigArgs(compile: *Compile) ![][]const u8 {
                             for (c_source_files.flags) |flag| {
                                 try zig_args.append(flag);
                             }
+
+                            if (c_source_files.precompiled_header) |pch| {
+                                try zig_args.append("-include-pch");
+                                try zig_args.append(pch.getPath(b));
+                                try zig_args.append("-fpch-validate-input-files-content");
+                            }
+
                             try zig_args.append("--");
                             prev_has_cflags = true;
                         }
diff --git a/test/standalone/build.zig.zon b/test/standalone/build.zig.zon
@@ -173,6 +173,9 @@
         .dependencyFromBuildZig = .{
             .path = "dependencyFromBuildZig",
         },
+        .precompiled_c_headers = .{
+            .path = "pch",
+        },
         .run_output_paths = .{
             .path = "run_output_paths",
         },
diff --git a/test/standalone/pch/build.zig b/test/standalone/pch/build.zig
@@ -0,0 +1,69 @@
+const std = @import("std");
+
+pub fn build(b: *std.Build) void {
+    const test_step = b.step("test", "Test it");
+    b.default_step = test_step;
+
+    const target = b.standardTargetOptions(.{});
+    const optimize = b.standardOptimizeOption(.{});
+
+    // c-header
+    {
+        const exe = b.addExecutable(.{
+            .name = "pchtest",
+            .target = target,
+            .optimize = optimize,
+            .link_libc = true,
+        });
+
+        const pch = b.addPrecompiledCHeader(.{
+            .name = "pch_c",
+            .target = target,
+            .optimize = optimize,
+            .link_libc = true,
+        }, .{
+            .file = b.path("include_a.h"),
+            .flags = &[_][]const u8{},
+            .lang = .h,
+        });
+
+        exe.addCSourceFiles(.{
+            .files = &.{"test.c"},
+            .flags = &[_][]const u8{},
+            .lang = .c,
+            .precompiled_header = pch.getEmittedBin(),
+        });
+
+        test_step.dependOn(&b.addRunArtifact(exe).step);
+    }
+
+    // c++-header
+    {
+        const exe = b.addExecutable(.{
+            .name = "pchtest++",
+            .target = target,
+            .optimize = optimize,
+            .link_libc = true,
+        });
+        exe.linkLibCpp();
+
+        const pch = b.addPrecompiledCHeader(.{
+            .name = "pch_c++",
+            .target = target,
+            .optimize = optimize,
+            .link_libcpp = true,
+        }, .{
+            .file = b.path("include_a.h"),
+            .flags = &[_][]const u8{},
+            .lang = .hpp,
+        });
+
+        exe.addCSourceFile(.{
+            .file = b.path("test.cpp"),
+            .flags = &[_][]const u8{},
+            .precompiled_header = pch.getEmittedBin(),
+        });
+
+        test_step.dependOn(&b.addRunArtifact(exe).step);
+    }
+}
diff --git a/test/standalone/pch/include_a.h b/test/standalone/pch/include_a.h
@@ -0,0 +1,15 @@
+#pragma once
+
+#include "include_b.h"
+
+#include <string.h>
+#include <stdlib.h>
+
+#if defined(__cplusplus)
+#include <iostream>
+#else
+#include <stdio.h>
+#endif
+
+#define A_INCLUDED 1
+
diff --git a/test/standalone/pch/include_b.h b/test/standalone/pch/include_b.h
@@ -0,0 +1,7 @@
+#pragma once
+
+#include <math.h>
+
+typedef double real;
+
+#define B_INCLUDED 1
diff --git a/test/standalone/pch/test.c b/test/standalone/pch/test.c
@@ -0,0 +1,22 @@
+
+// includes commented out to make sure the symbols come from the precompiled header.
+//#include "include_a.h"
+//#include "include_b.h"
+
+#ifndef A_INCLUDED
+#error "pch not included"
+#endif
+#ifndef B_INCLUDED
+#error "pch not included"
+#endif
+
+int main(int argc, char *argv[])
+{
+	real a = 0.123;
+
+	if (argc > 1) {
+		fprintf(stdout, "abs(%g)=%g\n", a, fabs(a));
+	}
+
+	return EXIT_SUCCESS;
+}
diff --git a/test/standalone/pch/test.cpp b/test/standalone/pch/test.cpp
@@ -0,0 +1,23 @@
+
+// includes commented out to make sure the symbols come from the precompiled header.
+//#include "includeA.h"
+//#include "includeB.h"
+
+#ifndef A_INCLUDED
+#error "pch not included"
+#endif
+#ifndef B_INCLUDED
+#error "pch not included"
+#endif
+
+int main(int argc, char *argv[])
+{
+	real a = -0.123;
+
+	if (argc > 1) {
+		std::cout << "abs(" << a << ")=" << fabs(a) << "\n";
+	}
+
+	return EXIT_SUCCESS;
+}
+
