[PATCH] D65517: [Preprocessor] Always discard body of #define if we failed to parse it

[Ilya Biryukov via Phabricator via cfe-commits]

ilya-biryukov updated this revision to Diff 212754.
ilya-biryukov marked an inline comment as done.
ilya-biryukov added a comment.

- Update a comment


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D65517/new/

https://reviews.llvm.org/D65517

Files:
  clang/lib/Lex/PPDirectives.cpp
  clang/test/Preprocessor/stringize_skipped.c
  clang/unittests/Tooling/Syntax/TokensTest.cpp


Index: clang/unittests/Tooling/Syntax/TokensTest.cpp
===================================================================
--- clang/unittests/Tooling/Syntax/TokensTest.cpp
+++ clang/unittests/Tooling/Syntax/TokensTest.cpp
@@ -298,6 +298,21 @@
   spelled tokens:
     <empty>
   no mappings.
+)"},
+      // Should not crash on errors inside '#define' directives. Error is that
+      // stringification (#B) does not refer to a macro parameter.
+      {
+          R"cpp(
+a
+#define MACRO() A #B
+)cpp",
+          R"(expanded tokens:
+  a
+file './input.cpp'
+  spelled tokens:
+    a # define MACRO ( ) A # B
+  mappings:
+    ['#'_1, '<eof>'_9) => ['<eof>'_1, '<eof>'_1)
 )"}};
   for (auto &Test : TestCases)
     EXPECT_EQ(collectAndDump(Test.first), Test.second)
Index: clang/test/Preprocessor/stringize_skipped.c
===================================================================
--- /dev/null
+++ clang/test/Preprocessor/stringize_skipped.c
@@ -0,0 +1,5 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+// Ensure we see the error from PP and do not see errors from the parser.
+
+// expected-error at +1{{'#' is not followed by a macro parameter}}
+#define INVALID() #B 10+10
Index: clang/lib/Lex/PPDirectives.cpp
===================================================================
--- clang/lib/Lex/PPDirectives.cpp
+++ clang/lib/Lex/PPDirectives.cpp
@@ -33,6 +33,7 @@
 #include "clang/Lex/Token.h"
 #include "clang/Lex/VariadicMacroSupport.h"
 #include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/ScopeExit.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/STLExtras.h"
@@ -2399,6 +2400,13 @@
   Token Tok;
   LexUnexpandedToken(Tok);
 
+  // Ensure we consume the rest of the macro body if errors occur.
+  auto _ = llvm::make_scope_exit([&]() {
+    // The flag indicates if we are still waiting for 'eod'.
+    if (CurLexer->ParsingPreprocessorDirective)
+      DiscardUntilEndOfDirective();
+  });
+
   // Used to un-poison and then re-poison identifiers of the __VA_ARGS__ ilk
   // within their appropriate context.
   VariadicMacroScopeGuard VariadicMacroScopeGuard(*this);
@@ -2420,12 +2428,8 @@
   } else if (Tok.is(tok::l_paren)) {
     // This is a function-like macro definition.  Read the argument list.
     MI->setIsFunctionLike();
-    if (ReadMacroParameterList(MI, LastTok)) {
-      // Throw away the rest of the line.
-      if (CurPPLexer->ParsingPreprocessorDirective)
-        DiscardUntilEndOfDirective();
+    if (ReadMacroParameterList(MI, LastTok))
       return nullptr;
-    }
 
     // If this is a definition of an ISO C/C++ variadic function-like macro (not
     // using the GNU named varargs extension) inform our variadic scope guard


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