[PATCH] D122748: [Sema] Don't check bounds for function pointer

[Aleksandr Platonov via Phabricator via cfe-commits]

ArcsinX created this revision.
ArcsinX added reviewers: aaron.ballman, erichkeane, abhinavgaba, 
chrish_ericsson_atx.
Herald added a project: All.
ArcsinX requested review of this revision.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.

Currently, clang crashes with i386 target on the following code:

  void f() {
    f + 0xdead000000000000UL;
  }

This problem is similar to the problem fixed in D104424 
<https://reviews.llvm.org/D104424>, but that fix can't handle function pointer 
case, because `getTypeSizeInCharsIfKnown()` says that size is known and equal 
to 0 for function type.

This patch prevents bounds checking for function pointer, thus fixes the crash.

Fixes https://github.com/llvm/llvm-project/issues/50463


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D122748

Files:
  clang/lib/Sema/SemaChecking.cpp
  clang/test/Sema/unbounded-array-bounds.c


Index: clang/test/Sema/unbounded-array-bounds.c
===================================================================
--- clang/test/Sema/unbounded-array-bounds.c
+++ clang/test/Sema/unbounded-array-bounds.c
@@ -80,3 +80,7 @@
   (void *)0 + 0xdead000000000000UL;
   // no array-bounds warning, and no crash
 }
+
+void func() {
+  func + 0xdead000000000000UL; // no crash
+}
Index: clang/lib/Sema/SemaChecking.cpp
===================================================================
--- clang/lib/Sema/SemaChecking.cpp
+++ clang/lib/Sema/SemaChecking.cpp
@@ -15447,7 +15447,7 @@
   const Type *BaseType =
       ArrayTy == nullptr ? nullptr : ArrayTy->getElementType().getTypePtr();
   bool IsUnboundedArray = (BaseType == nullptr);
-  if (EffectiveType->isDependentType() ||
+  if (EffectiveType->isDependentType() || EffectiveType->isFunctionType() ||
       (!IsUnboundedArray && BaseType->isDependentType()))
     return;
 



Index: clang/test/Sema/unbounded-array-bounds.c
===================================================================
--- clang/test/Sema/unbounded-array-bounds.c
+++ clang/test/Sema/unbounded-array-bounds.c
@@ -80,3 +80,7 @@
   (void *)0 + 0xdead000000000000UL;
   // no array-bounds warning, and no crash
 }
+
+void func() {
+  func + 0xdead000000000000UL; // no crash
+}
Index: clang/lib/Sema/SemaChecking.cpp
===================================================================
--- clang/lib/Sema/SemaChecking.cpp
+++ clang/lib/Sema/SemaChecking.cpp
@@ -15447,7 +15447,7 @@
   const Type *BaseType =
       ArrayTy == nullptr ? nullptr : ArrayTy->getElementType().getTypePtr();
   bool IsUnboundedArray = (BaseType == nullptr);
-  if (EffectiveType->isDependentType() ||
+  if (EffectiveType->isDependentType() || EffectiveType->isFunctionType() ||
       (!IsUnboundedArray && BaseType->isDependentType()))
     return;
 

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