[clang] 4272847 - [clang][deps] Don't treat ObjC method args as module directives (#97654)

[via cfe-commits]

Author: Michael Spencer
Date: 2024-07-18T13:37:01-07:00
New Revision: 4272847546225bcf2e83e09e3a620bf286c058fd

URL: https://github.com/llvm/llvm-project/commit/4272847546225bcf2e83e09e3a620bf286c058fd
DIFF: https://github.com/llvm/llvm-project/commit/4272847546225bcf2e83e09e3a620bf286c058fd.diff

LOG: [clang][deps] Don't treat ObjC method args as module directives (#97654)

`import:(type)name` is a method argument decl in ObjC, but the C++20
preprocessing rules say this is a preprocessing line.

Because the dependency directive scanner is not language dependent, this
patch extends the C++20 rule to exclude `module :` (which is never a
valid module decl anyway), and `import :` that is not followed by an
identifier.

This is ok to do because in C++20 mode the compiler will later error on
lines like this anyway, and the dependencies the scanner returns are
still correct.

Added: 
    

Modified: 
    clang/lib/Lex/DependencyDirectivesScanner.cpp
    clang/unittests/Lex/DependencyDirectivesScannerTest.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/Lex/DependencyDirectivesScanner.cpp b/clang/lib/Lex/DependencyDirectivesScanner.cpp
index 57652be8244b4..8a020d0e95fe3 100644
--- a/clang/lib/Lex/DependencyDirectivesScanner.cpp
+++ b/clang/lib/Lex/DependencyDirectivesScanner.cpp
@@ -660,7 +660,18 @@ bool Scanner::lexModule(const char *&First, const char *const End) {
   // an import.
 
   switch (*First) {
-  case ':':
+  case ':': {
+    // `module :` is never the start of a valid module declaration.
+    if (Id == "module") {
+      skipLine(First, End);
+      return false;
+    }
+    // `import:(type)name` is a valid ObjC method decl, so check one more token.
+    (void)lexToken(First, End);
+    if (!tryLexIdentifierOrSkipLine(First, End))
+      return false;
+    break;
+  }
   case '<':
   case '"':
     break;

diff  --git a/clang/unittests/Lex/DependencyDirectivesScannerTest.cpp b/clang/unittests/Lex/DependencyDirectivesScannerTest.cpp
index 94af9688a96e2..23304fff950eb 100644
--- a/clang/unittests/Lex/DependencyDirectivesScannerTest.cpp
+++ b/clang/unittests/Lex/DependencyDirectivesScannerTest.cpp
@@ -970,6 +970,23 @@ ort \
   EXPECT_EQ(Directives[1].Kind, cxx_export_module_decl);
 }
 
+TEST(MinimizeSourceToDependencyDirectivesTest, ObjCMethodArgs) {
+  SmallVector<char, 128> Out;
+
+  StringRef Source = R"(
+    @interface SomeObjcClass
+      - (void)func:(int)otherData
+              module:(int)module
+              import:(int)import;
+    @end
+  )";
+
+  ASSERT_FALSE(minimizeSourceToDependencyDirectives(Source, Out));
+  // `module :` and `import :` not followed by an identifier are not treated as
+  // directive lines because they can be method argument decls.
+  EXPECT_STREQ("<TokBeforeEOF>\n", Out.data());
+}
+
 TEST(MinimizeSourceToDependencyDirectivesTest, TokensBeforeEOF) {
   SmallString<128> Out;