Driver: implement -undef CLI option

Closes #521
Vexu · Nov 8, 2023 · 0b0b60f · 0b0b60f
1 parent ae21a15
commit 0b0b60f
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Showing 6 changed files with 72 additions and 39 deletions.
diff --git a/src/Builtins.zig b/src/Builtins.zig
@@ -355,7 +355,7 @@ test Iterator {
 test "All builtins" {
     var comp = Compilation.init(std.testing.allocator);
     defer comp.deinit();
-    _ = try comp.generateBuiltinMacros();
+    _ = try comp.generateBuiltinMacros(.include_system_defines);
     var arena = std.heap.ArenaAllocator.init(std.testing.allocator);
     defer arena.deinit();
 
@@ -378,7 +378,7 @@ test "Allocation failures" {
         fn testOne(allocator: std.mem.Allocator) !void {
             var comp = Compilation.init(allocator);
             defer comp.deinit();
-            _ = try comp.generateBuiltinMacros();
+            _ = try comp.generateBuiltinMacros(.include_system_defines);
             var arena = std.heap.ArenaAllocator.init(comp.gpa);
             defer arena.deinit();
 

diff --git a/src/Compilation.zig b/src/Compilation.zig
@@ -219,32 +219,15 @@ fn generateDateAndTime(w: anytype, timestamp: u47) !void {
     });
 }
 
-/// Generate builtin macros that will be available to each source file.
-pub fn generateBuiltinMacros(comp: *Compilation) !Source {
-    try comp.generateBuiltinTypes();
-
-    var buf = std.ArrayList(u8).init(comp.gpa);
-    defer buf.deinit();
-    const w = buf.writer();
+/// Which set of system defines to generate via generateBuiltinMacros
+pub const SystemDefinesMode = enum {
+    /// Only define macros required by the C standard (date/time macros and those beginning with `__STDC`)
+    no_system_defines,
+    /// Define the standard set of system macros
+    include_system_defines,
+};
 
-    // standard macros
-    try w.writeAll(
-        \\#define __VERSION__ "Aro 
-    ++ @import("lib.zig").version_str ++ "\"\n" ++
-        \\#define __Aro__
-        \\#define __STDC__ 1
-        \\#define __STDC_HOSTED__ 1
-        \\#define __STDC_NO_ATOMICS__ 1
-        \\#define __STDC_NO_COMPLEX__ 1
-        \\#define __STDC_NO_THREADS__ 1
-        \\#define __STDC_NO_VLA__ 1
-        \\#define __STDC_UTF_16__ 1
-        \\#define __STDC_UTF_32__ 1
-        \\
-    );
-    if (comp.langopts.standard.StdCVersionMacro()) |stdc_version| {
-        try w.print("#define __STDC_VERSION__ {s}\n", .{stdc_version});
-    }
+fn generateSystemDefines(comp: *Compilation, w: anytype) !void {
     const ptr_width = comp.target.ptrBitWidth();
 
     // os macros
@@ -414,10 +397,6 @@ pub fn generateBuiltinMacros(comp: *Compilation) !Source {
         \\
     );
 
-    // timestamps
-    const timestamp = try comp.getTimestamp();
-    try generateDateAndTime(w, timestamp);
-
     // types
     if (comp.getCharSignedness() == .unsigned) try w.writeAll("#define __CHAR_UNSIGNED__ 1\n");
     try w.writeAll("#define __CHAR_BIT__ 8\n");
@@ -489,6 +468,49 @@ pub fn generateBuiltinMacros(comp: *Compilation) !Source {
         \\#define __DECIMAL_DIG__ __LDBL_DECIMAL_DIG__
         \\
     );
+}
+
+/// Generate builtin macros that will be available to each source file.
+pub fn generateBuiltinMacros(comp: *Compilation, system_defines_mode: SystemDefinesMode) !Source {
+    try comp.generateBuiltinTypes();
+
+    var buf = std.ArrayList(u8).init(comp.gpa);
+    defer buf.deinit();
+
+    if (system_defines_mode == .include_system_defines) {
+        try buf.appendSlice(
+            \\#define __VERSION__ "Aro 
+        ++ @import("lib.zig").version_str ++ "\"\n" ++
+            \\#define __Aro__
+            \\
+        );
+    }
+
+    // standard macros
+    try buf.appendSlice(
+        \\#define __STDC__ 1
+        \\#define __STDC_HOSTED__ 1
+        \\#define __STDC_NO_ATOMICS__ 1
+        \\#define __STDC_NO_COMPLEX__ 1
+        \\#define __STDC_NO_THREADS__ 1
+        \\#define __STDC_NO_VLA__ 1
+        \\#define __STDC_UTF_16__ 1
+        \\#define __STDC_UTF_32__ 1
+        \\
+    );
+    if (comp.langopts.standard.StdCVersionMacro()) |stdc_version| {
+        try buf.appendSlice("#define __STDC_VERSION__ ");
+        try buf.appendSlice(stdc_version);
+        try buf.append('\n');
+    }
+
+    // timestamps
+    const timestamp = try comp.getTimestamp();
+    try generateDateAndTime(buf.writer(), timestamp);
+
+    if (system_defines_mode == .include_system_defines) {
+        try comp.generateSystemDefines(buf.writer());
+    }
 
     return comp.addSourceFromBuffer("<builtin>", buf.items);
 }

diff --git a/src/Driver.zig b/src/Driver.zig
@@ -27,6 +27,7 @@ inputs: std.ArrayListUnmanaged(Source) = .{},
 link_objects: std.ArrayListUnmanaged([]const u8) = .{},
 output_name: ?[]const u8 = null,
 sysroot: ?[]const u8 = null,
+system_defines: Compilation.SystemDefinesMode = .include_system_defines,
 temp_file_count: u32 = 0,
 /// If false, do not emit line directives in -E mode
 line_commands: bool = true,
@@ -131,6 +132,7 @@ pub const usage =
     \\  --sysroot=<dir>         Use dir as the logical root directory for headers and libraries (not fully implemented)
     \\  --target=<value>        Generate code for the given target
     \\  -U <macro>              Undefine <macro>
+    \\  -undef                  Do not predefine any system-specific macros. Standard predefined macros remain defined.
     \\  -Werror                 Treat all warnings as errors
     \\  -Werror=<warning>       Treat warning as error
     \\  -W<warning>             Enable the specified warning
@@ -218,6 +220,8 @@ pub fn parseArgs(
                     macro = args[i];
                 }
                 try macro_buf.print("#undef {s}\n", .{macro});
+            } else if (mem.eql(u8, arg, "-undef")) {
+                d.system_defines = .no_system_defines;
             } else if (mem.eql(u8, arg, "-c") or mem.eql(u8, arg, "--compile")) {
                 d.only_compile = true;
             } else if (mem.eql(u8, arg, "-E")) {
@@ -497,7 +501,7 @@ pub fn main(d: *Driver, tc: *Toolchain, args: []const []const u8) !void {
         error.AroIncludeNotFound => return d.fatal("unable to find Aro builtin headers", .{}),
     };
 
-    const builtin = try d.comp.generateBuiltinMacros();
+    const builtin = try d.comp.generateBuiltinMacros(d.system_defines);
     const user_macros = try d.comp.addSourceFromBuffer("<command line>", macro_buf.items);
 
     const fast_exit = @import("builtin").mode != .Debug;

diff --git a/test/cases/undef.c b/test/cases/undef.c
@@ -0,0 +1,5 @@
+//aro-args -undef --target=x86_64-linux-gnu
+
+#if defined(linux) || defined(__linux) || defined(__linux__)
+#error Should not be defined
+#endif
diff --git a/test/record_runner.zig b/test/record_runner.zig
@@ -268,7 +268,7 @@ fn singleRun(alloc: std.mem.Allocator, test_dir: []const u8, test_case: TestCase
     }
 
     const user_macros = try comp.addSourceFromBuffer("<command line>", macro_buf.items);
-    const builtin_macros = try comp.generateBuiltinMacros();
+    const builtin_macros = try comp.generateBuiltinMacros(.include_system_defines);
 
     var pp = aro.Preprocessor.init(&comp);
     defer pp.deinit();

diff --git a/test/runner.zig b/test/runner.zig
@@ -11,9 +11,10 @@ const AllocatorError = std.mem.Allocator.Error;
 var general_purpose_allocator = std.heap.GeneralPurposeAllocator(.{}){};
 
 /// Returns only_preprocess and line_markers settings if saw -E
-fn addCommandLineArgs(comp: *aro.Compilation, file: aro.Source, macro_buf: anytype) !struct { bool, aro.Preprocessor.Linemarkers } {
+fn addCommandLineArgs(comp: *aro.Compilation, file: aro.Source, macro_buf: anytype) !struct { bool, aro.Preprocessor.Linemarkers, aro.Compilation.SystemDefinesMode } {
     var only_preprocess = false;
     var line_markers: aro.Preprocessor.Linemarkers = .none;
+    var system_defines: aro.Compilation.SystemDefinesMode = .include_system_defines;
     if (std.mem.startsWith(u8, file.buf, "//aro-args")) {
         var test_args = std.ArrayList([]const u8).init(comp.gpa);
         defer test_args.deinit();
@@ -25,6 +26,7 @@ fn addCommandLineArgs(comp: *aro.Compilation, file: aro.Source, macro_buf: anyty
         defer driver.deinit();
         _ = try driver.parseArgs(std.io.null_writer, macro_buf, test_args.items);
         only_preprocess = driver.only_preprocess;
+        system_defines = driver.system_defines;
         if (only_preprocess) {
             if (driver.line_commands) {
                 line_markers = if (driver.use_line_directives) .line_directives else .numeric_directives;
@@ -47,7 +49,7 @@ fn addCommandLineArgs(comp: *aro.Compilation, file: aro.Source, macro_buf: anyty
         }
     }
 
-    return .{ only_preprocess, line_markers };
+    return .{ only_preprocess, line_markers, system_defines };
 }
 
 fn testOne(allocator: std.mem.Allocator, path: []const u8, test_dir: []const u8) !void {
@@ -61,10 +63,10 @@ fn testOne(allocator: std.mem.Allocator, path: []const u8, test_dir: []const u8)
     var macro_buf = std.ArrayList(u8).init(comp.gpa);
     defer macro_buf.deinit();
 
-    _ = try addCommandLineArgs(&comp, file, macro_buf.writer());
+    _, _, const system_defines = try addCommandLineArgs(&comp, file, macro_buf.writer());
     const user_macros = try comp.addSourceFromBuffer("<command line>", macro_buf.items);
 
-    const builtin_macros = try comp.generateBuiltinMacros();
+    const builtin_macros = try comp.generateBuiltinMacros(system_defines);
 
     var pp = aro.Preprocessor.init(&comp);
     defer pp.deinit();
@@ -209,10 +211,10 @@ pub fn main() !void {
         var macro_buf = std.ArrayList(u8).init(comp.gpa);
         defer macro_buf.deinit();
 
-        const only_preprocess, const linemarkers = try addCommandLineArgs(&comp, file, macro_buf.writer());
+        const only_preprocess, const linemarkers, const system_defines = try addCommandLineArgs(&comp, file, macro_buf.writer());
         const user_macros = try comp.addSourceFromBuffer("<command line>", macro_buf.items);
 
-        const builtin_macros = try comp.generateBuiltinMacros();
+        const builtin_macros = try comp.generateBuiltinMacros(system_defines);
 
         comp.diag.errors = 0;
         var pp = aro.Preprocessor.init(&comp);