PR16339: Don't produce a diagnostic pointing at the whitespace between a '#if'

and a '!defined(X)' if we find a broken header guard. This is suboptimal; we
should point the diagnostic at the 'X' token not the 'if' token, but it fixes
the crash.

llvm-svn: 184054

3 files changed, 17 insertions, 2 deletions

diff --git a/clang/lib/Lex/PPDirectives.cpp b/clang/lib/Lex/PPDirectives.cpp
index 0cfdac92d23..3e3312a9261 100644
--- a/clang/lib/Lex/PPDirectives.cpp
+++ b/clang/lib/Lex/PPDirectives.cpp
@@ -2132,7 +2132,8 @@ void Preprocessor::HandleIfDirective(Token &IfToken,
   // directive seen, handle it for the multiple-include optimization.
   if (CurPPLexer->getConditionalStackDepth() == 0) {
     if (!ReadAnyTokensBeforeDirective && IfNDefMacro && ConditionalTrue)
-      CurPPLexer->MIOpt.EnterTopLevelIfndef(IfNDefMacro, ConditionalBegin);
+      // FIXME: Pass in the location of the macro name, not the 'if' token.
+      CurPPLexer->MIOpt.EnterTopLevelIfndef(IfNDefMacro, IfToken.getLocation());
     else
       CurPPLexer->MIOpt.EnterTopLevelConditional();
   }
diff --git a/clang/test/Lexer/Inputs/bad-header-guard-defined.h b/clang/test/Lexer/Inputs/bad-header-guard-defined.h
new file mode 100644
index 00000000000..b28f1a8873e
--- /dev/null
+++ b/clang/test/Lexer/Inputs/bad-header-guard-defined.h
@@ -0,0 +1,4 @@
+#if !defined(foo)
+#define goo
+int n;
+#endif
diff --git a/clang/test/Lexer/header.cpp b/clang/test/Lexer/header.cpp
index 278ff2e4323..047240ac0f7 100644
--- a/clang/test/Lexer/header.cpp
+++ b/clang/test/Lexer/header.cpp
@@ -17,6 +17,16 @@
 // CHECK: {{^}}        ^~~~~~~~~
 // CHECK: {{^}}        bad_header_guard
 
+#include "Inputs/bad-header-guard-defined.h"
+// CHECK: In file included from {{.*}}header.cpp:{{[0-9]*}}:
+// CHECK: {{.*}}bad-header-guard-defined.h:1:2: warning: 'foo' is used as a header guard here, followed by #define of a different macro
+// CHECK: {{^}}#if !defined(foo)
+// CHECK: {{^}} ^~
+// CHECK: {{.*}}bad-header-guard-defined.h:2:9: note: 'goo' is defined here; did you mean 'foo'?
+// CHECK: {{^}}#define goo
+// CHECK: {{^}}        ^~~
+// CHECK: {{^}}        foo
+
 #include "Inputs/multiple.h"
 #include "Inputs/multiple.h"
 #include "Inputs/multiple.h"
@@ -30,4 +40,4 @@
 // CHECK: {{^}}        ^~~~~
 // CHECK: {{^}}        multiple
 
-// CHECK: 2 warnings generated.
+// CHECK: 3 warnings generated.