[PATCH] D114559: [clang] ASTMatchers: Fix out-of-bounds access in foreachArgumentWithParamType.

[Felix Berger via Phabricator via cfe-commits]

flx created this revision.
flx requested review of this revision.
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The matcher crashes when a variadic function pointer is invoked because the
FunctionProtoType has fewer parameters than arguments.

Matching of non-variadic arguments now works.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D114559

Files:
  clang/include/clang/ASTMatchers/ASTMatchers.h
  clang/unittests/ASTMatchers/ASTMatchersTraversalTest.cpp


Index: clang/unittests/ASTMatchers/ASTMatchersTraversalTest.cpp
===================================================================
--- clang/unittests/ASTMatchers/ASTMatchersTraversalTest.cpp
+++ clang/unittests/ASTMatchers/ASTMatchersTraversalTest.cpp
@@ -1094,6 +1094,31 @@
       S, CallExpr, std::make_unique<VerifyIdIsBoundTo<DeclRefExpr>>("arg")));
 }
 
+TEST(ForEachArgumentWithParamType, MatchesVariadicFunctionPtrCalls) {
+  StatementMatcher ArgumentY =
+      declRefExpr(to(varDecl(hasName("y")))).bind("arg");
+  TypeMatcher IntType = qualType(builtinType()).bind("type");
+  StatementMatcher CallExpr =
+      callExpr(forEachArgumentWithParamType(ArgumentY, IntType));
+
+  StringRef S = R"cpp(
+    void fcntl(int fd, int cmd, ...) {}
+
+    template <typename Func>
+    void f(Func F) {
+      int y = 42;
+      F(y, 1, 3);
+    }
+
+    void g() { f(fcntl); }
+  )cpp";
+
+  EXPECT_TRUE(matchAndVerifyResultTrue(
+      S, CallExpr, std::make_unique<VerifyIdIsBoundTo<QualType>>("type")));
+  EXPECT_TRUE(matchAndVerifyResultTrue(
+      S, CallExpr, std::make_unique<VerifyIdIsBoundTo<DeclRefExpr>>("arg")));
+}
+
 TEST(QualType, hasCanonicalType) {
   EXPECT_TRUE(notMatches("typedef int &int_ref;"
                            "int a;"
Index: clang/include/clang/ASTMatchers/ASTMatchers.h
===================================================================
--- clang/include/clang/ASTMatchers/ASTMatchers.h
+++ clang/include/clang/ASTMatchers/ASTMatchers.h
@@ -4885,7 +4885,7 @@
 
       // This test is cheaper compared to the big matcher in the next if.
       // Therefore, please keep this order.
-      if (FProto) {
+      if (FProto && FProto->getNumParams() > ParamIndex) {
         QualType ParamType = FProto->getParamType(ParamIndex);
         if (ParamMatcher.matches(ParamType, Finder, &ParamMatches)) {
           Result.addMatch(ParamMatches);


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