When we expect two arguments but have zero, make sure to add

two empty arguments.  Also, add an assert so that this bug
manifests as an assertion failure, not a valgrind problem.

This fixes rdar://6880648 - [cpp] crash in ArgNeedsPreexpansion

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@71616 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Lex/MacroArgs.cpp b/lib/Lex/MacroArgs.cpp
index 2646a61e51af271f07c247de54e1f3bbe9054303..cba69b7d79190836c5d5cd6906ef4e66b9e01143 100644 (file)
--- a/lib/Lex/MacroArgs.cpp
+++ b/lib/Lex/MacroArgs.cpp
@@ -72,6 +72,7 @@ const Token *MacroArgs::getUnexpArgument(unsigned Arg) const {
     if (Result->is(tok::eof))
       --Arg;
   }
+  assert(Result < Start+NumUnexpArgTokens && "Invalid arg #");
   return Result;
 }
 

diff --git a/lib/Lex/PPMacroExpansion.cpp b/lib/Lex/PPMacroExpansion.cpp
index 48c166daba26891bc1d528e6432894cbf124f3a5..18dcfb25e7d32926b39e1e9ec4419346feac2e10 100644 (file)
--- a/lib/Lex/PPMacroExpansion.cpp
+++ b/lib/Lex/PPMacroExpansion.cpp
@@ -427,6 +427,11 @@ MacroArgs *Preprocessor::ReadFunctionLikeMacroArgs(Token &MacroName,
     Tok.setLocation(EndLoc);
     Tok.setLength(0);
     ArgTokens.push_back(Tok);
+
+    // If we expect two arguments, add both as empty.
+    if (NumActuals == 0 && MinArgsExpected == 2)
+      ArgTokens.push_back(Tok);
+    
   } else if (NumActuals > MinArgsExpected && !MI->isVariadic()) {
     // Emit the diagnostic at the macro name in case there is a missing ).
     // Emitting it at the , could be far away from the macro name.

diff --git a/test/Preprocessor/macro_expand.c b/test/Preprocessor/macro_expand.c
index c2c76bddbf03300ee49d012d8319e739d3c1e9a6..74b3922d1e13fc0ef9e96e63503640eb950677ad 100644 (file)
--- a/test/Preprocessor/macro_expand.c
+++ b/test/Preprocessor/macro_expand.c
@@ -14,3 +14,6 @@ A: X()()()
 B: f(f))
 C: for(for))
 
+// rdar://6880648
+#define f(x,y...) y
+f()