Preprocessor+Parser: detect system headers and don't apply indirect include rule to them

Author: Vexu

src/Compilation.zig

@@ -529,6 +529,7 @@ pub fn addSourceFromReader(
     path: []const u8,
     contents: []u8,
     included_automatically: bool,
+    system_header_file: bool,
 ) !Source {
     const duped_path = try comp.gpa.dupe(u8, path);
     errdefer comp.gpa.free(duped_path);
@@ -618,6 +619,7 @@ pub fn addSourceFromReader(
         .id = source_id,
         .path = duped_path,
         .included_automatically = included_automatically,
+        .system_header_file = system_header_file,
         .buf = if (i == contents.len) contents else try comp.gpa.realloc(contents, i),
         .splice_locs = splice_locs,
     };
@@ -637,11 +639,11 @@ pub fn addSourceFromBuffer(comp: *Compilation, path: []const u8, buf: []const u8
     const contents = try comp.gpa.alloc(u8, buf.len);
     errdefer comp.gpa.free(contents);
 
-    return comp.addSourceFromReader(reader, path, contents, true);
+    return comp.addSourceFromReader(reader, path, contents, true, false);
 }
 
 /// Caller retains ownership of `path`
-pub fn addSourceFromPath(comp: *Compilation, path: []const u8) !Source {
+pub fn addSourceFromPath(comp: *Compilation, path: []const u8, system_header_file: bool) !Source {
     if (comp.sources.get(path)) |some| return some;
 
     if (mem.indexOfScalar(u8, path, 0) != null) {
@@ -657,7 +659,7 @@ pub fn addSourceFromPath(comp: *Compilation, path: []const u8) !Source {
     const contents = try comp.gpa.alloc(u8, size);
     errdefer comp.gpa.free(contents);
 
-    return comp.addSourceFromReader(reader, path, contents, false);
+    return comp.addSourceFromReader(reader, path, contents, false, system_header_file);
 }
 
 pub fn findInclude(comp: *Compilation, tok: Token, filename: []const u8, search_cwd: bool) !?Source {
@@ -669,7 +671,7 @@ pub fn findInclude(comp: *Compilation, tok: Token, filename: []const u8, search_
             std.fs.path.join(fib.allocator(), &.{ some, filename }) catch break :blk
         else
             std.fs.path.join(fib.allocator(), &.{ ".", filename }) catch break :blk;
-        if (comp.addSourceFromPath(path)) |some|
+        if (comp.addSourceFromPath(path, false)) |some|
             return some
         else |err| switch (err) {
             error.OutOfMemory => return error.OutOfMemory,
@@ -679,7 +681,7 @@ pub fn findInclude(comp: *Compilation, tok: Token, filename: []const u8, search_
     for (comp.include_dirs.items) |dir| {
         fib.end_index = 0;
         const path = std.fs.path.join(fib.allocator(), &.{ dir, filename }) catch continue;
-        if (comp.addSourceFromPath(path)) |some|
+        if (comp.addSourceFromPath(path, false)) |some|
             return some
         else |err| switch (err) {
             error.OutOfMemory => return error.OutOfMemory,
@@ -689,7 +691,7 @@ pub fn findInclude(comp: *Compilation, tok: Token, filename: []const u8, search_
     for (comp.system_include_dirs.items) |dir| {
         fib.end_index = 0;
         const path = std.fs.path.join(fib.allocator(), &.{ dir, filename }) catch continue;
-        if (comp.addSourceFromPath(path)) |some|
+        if (comp.addSourceFromPath(path, true)) |some|
             return some
         else |err| switch (err) {
             error.OutOfMemory => return error.OutOfMemory,
@@ -785,7 +787,7 @@ test "addSourceFromReader" {
             const contents = try comp.gpa.alloc(u8, 1024);
 
             var reader = std.io.fixedBufferStream(str).reader();
-            const source = try comp.addSourceFromReader(reader, "path", contents, false);
+            const source = try comp.addSourceFromReader(reader, "path", contents, false, false);
 
             try std.testing.expectEqualStrings(expected, source.buf);
             try std.testing.expectEqual(warning_count, @intCast(u32, comp.diag.list.items.len));

src/Parser.zig

@@ -392,6 +392,7 @@ fn checkIndirectInclude(p: *Parser, usage_tok: TokenIndex, source_tok: TokenInde
     if (locs[usage_tok].id == .generated) return;
     if (locs[usage_tok].id == locs[source_tok].id) return; // in same file
     const usage_src = p.pp.comp.getSource(locs[usage_tok].id);
+    if (usage_src.system_header_file) return; // do not apply rule to system header files
     if (usage_src.direct_includes.get(locs[source_tok].id) != null) return; // directly included
 
     try p.errTok(.indirect_use_of_ident, usage_tok);

src/Preprocessor.zig

@@ -1195,6 +1195,7 @@ fn checkIndirectInclude(pp: *Preprocessor, source_loc: Source.Location) !void {
     if (source.included_automatically) return; // macro is included automatically and always visible
     if (pp.expansion_source_loc.id == source_loc.id) return; // in same file
     const usage_src = pp.comp.getSource(pp.expansion_source_loc.id);
+    if (usage_src.system_header_file) return; // do not apply rule to system header files
     if (usage_src.direct_includes.get(source_loc.id) != null) return; // directly included
 
     try pp.comp.diag.add(.{ .tag = .indirect_use_of_ident, .loc = pp.expansion_source_loc }, &.{});

src/Source.zig

@@ -24,6 +24,7 @@ buf: []const u8,
 id: Id,
 /// True if this source is included in the preprocessor without an explicit #include
 included_automatically: bool = false,
+system_header_file: bool = false,
 invalid_utf8_loc: ?Location = null,
 /// each entry represents a byte position within `buf` where a backslash+newline was deleted
 /// from the original raw buffer. The same position can appear multiple times if multiple

src/main.zig

@@ -236,7 +236,7 @@ pub fn parseArgs(comp: *Compilation, std_out: anytype, sources: *std.ArrayList(S
                 try comp.diag.add(.{ .tag = .cli_unknown_arg, .extra = .{ .str = arg } }, &.{});
             }
         } else {
-            const file = comp.addSourceFromPath(arg) catch |err| {
+            const file = comp.addSourceFromPath(arg, false) catch |err| {
                 return fatal(comp, "{s} when trying to add source file", .{@errorName(err)});
             };
             try sources.append(file);

test/runner.zig

@@ -86,7 +86,7 @@ pub fn main() !void {
         defer case_node.end();
         progress.refresh();
 
-        const file = comp.addSourceFromPath(path) catch |err| {
+        const file = comp.addSourceFromPath(path, false) catch |err| {
             fail_count += 1;
             progress.log("could not add source '{s}': {s}\n", .{ path, @errorName(err) });
             continue;