[clang] cae3b70 - [PR49761] Fix variadic arg handling in matcher

[via cfe-commits]

Author: Chris Hamilton
Date: 2021-04-23T12:07:14-05:00
New Revision: cae3b70cebc1b7b762a8b466cafca2d4189e72a7

URL: https://github.com/llvm/llvm-project/commit/cae3b70cebc1b7b762a8b466cafca2d4189e72a7
DIFF: https://github.com/llvm/llvm-project/commit/cae3b70cebc1b7b762a8b466cafca2d4189e72a7.diff

LOG: [PR49761] Fix variadic arg handling in matcher

Mishandling of variadic arguments in a function call caused a crash
(runtime assert fail) in bugprone-infinite-loop tidy checker.  Fix
is to limit argument matching to the lesser of the number of variadic
params in the prototype or the number of actual args in the call.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D101108

Added: 
    

Modified: 
    clang-tools-extra/test/clang-tidy/checkers/bugprone-infinite-loop.cpp
    clang/include/clang/ASTMatchers/ASTMatchers.h

Removed: 
    


################################################################################
diff  --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone-infinite-loop.cpp b/clang-tools-extra/test/clang-tidy/checkers/bugprone-infinite-loop.cpp
index 8bd4df7cd8445..0b1baf04fee2f 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/bugprone-infinite-loop.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone-infinite-loop.cpp
@@ -386,3 +386,18 @@ void evaluatable(bool CondVar) {
   do {
   } while (false && CondVar);
 }
+
+struct logger {
+  void (*debug)(struct logger *, const char *, ...);
+};
+
+int foo(void) {
+  struct logger *pl = 0;
+  int iterator = 0;
+  while (iterator < 10) {
+    char *l_tmp_msg = 0;
+    pl->debug(pl, "%d: %s\n", iterator, l_tmp_msg);
+    iterator++;
+  }
+  return 0;
+}

diff  --git a/clang/include/clang/ASTMatchers/ASTMatchers.h b/clang/include/clang/ASTMatchers/ASTMatchers.h
index 33f57b755941f..fbf98d9f7af07 100644
--- a/clang/include/clang/ASTMatchers/ASTMatchers.h
+++ b/clang/include/clang/ASTMatchers/ASTMatchers.h
@@ -4757,8 +4757,11 @@ AST_POLYMORPHIC_MATCHER_P2(forEachArgumentWithParamType,
 
   int ParamIndex = 0;
   bool Matched = false;
+  unsigned NumArgs = Node.getNumArgs();
+  if (FProto && FProto->isVariadic())
+    NumArgs = std::min(NumArgs, FProto->getNumParams());
 
-  for (; ArgIndex < Node.getNumArgs(); ++ArgIndex, ++ParamIndex) {
+  for (; ArgIndex < NumArgs; ++ArgIndex, ++ParamIndex) {
     BoundNodesTreeBuilder ArgMatches(*Builder);
     if (ArgMatcher.matches(*(Node.getArg(ArgIndex)->IgnoreParenCasts()), Finder,
                            &ArgMatches)) {