[clang] 52bf531 - [Clang][Sema] Fix out-of-bounds access (#80978)

[via cfe-commits]

Author: Sirraide
Date: 2024-02-07T15:12:15+01:00
New Revision: 52bf531630d19e115d30b4ca46f1ef03b9a724c6

URL: https://github.com/llvm/llvm-project/commit/52bf531630d19e115d30b4ca46f1ef03b9a724c6
DIFF: https://github.com/llvm/llvm-project/commit/52bf531630d19e115d30b4ca46f1ef03b9a724c6.diff

LOG: [Clang][Sema] Fix out-of-bounds access (#80978)

Trying to compile a C-style variadic member function with an explicit
object parameter was crashing in Sema because of an out-of-bounds
access.

This fixes #80971.

Added: 
    

Modified: 
    clang/docs/ReleaseNotes.rst
    clang/lib/Sema/SemaOverload.cpp
    clang/test/SemaCXX/cxx2b-deducing-this.cpp

Removed: 
    


################################################################################
diff  --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 802c44b6c86080..52a48c750fe55b 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -208,6 +208,8 @@ Bug Fixes to C++ Support
   parameter where we did an incorrect specialization of the initialization of
   the default parameter.
   Fixes (`#68490 <https://github.com/llvm/llvm-project/issues/68490>`_)
+- Fix a crash when trying to call a varargs function that also has an explicit object parameter.
+  Fixes (`#80971 ICE when explicit object parameter be a function parameter pack`)
 
 Bug Fixes to AST Handling
 ^^^^^^^^^^^^^^^^^^^^^^^^^

diff  --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp
index c46f6338a5a125..42960c229077c3 100644
--- a/clang/lib/Sema/SemaOverload.cpp
+++ b/clang/lib/Sema/SemaOverload.cpp
@@ -7722,8 +7722,8 @@ bool Sema::CheckNonDependentConversions(
   unsigned Offset =
       Method && Method->hasCXXExplicitFunctionObjectParameter() ? 1 : 0;
 
-  for (unsigned I = 0, N = std::min(ParamTypes.size(), Args.size()); I != N;
-       ++I) {
+  for (unsigned I = 0, N = std::min(ParamTypes.size() - Offset, Args.size());
+       I != N; ++I) {
     QualType ParamType = ParamTypes[I + Offset];
     if (!ParamType->isDependentType()) {
       unsigned ConvIdx;

diff  --git a/clang/test/SemaCXX/cxx2b-deducing-this.cpp b/clang/test/SemaCXX/cxx2b-deducing-this.cpp
index aab35828096a8e..30131d6adc4db0 100644
--- a/clang/test/SemaCXX/cxx2b-deducing-this.cpp
+++ b/clang/test/SemaCXX/cxx2b-deducing-this.cpp
@@ -636,3 +636,13 @@ struct D {
     }
 };
 }
+
+namespace GH80971 {
+struct S {
+  auto f(this auto self...) {  }
+};
+
+int bug() {
+  S{}.f(0);
+}
+}