[clang-tools-extra] ecdc528 - [Clang] Fix crash in __builtin_assume_aligned (#114217)

[via cfe-commits]

Author: Oliver Stannard
Date: 2024-12-19T10:34:56Z
New Revision: ecdc5289afec1af98640b6375a52aaf448fe7388

URL: https://github.com/llvm/llvm-project/commit/ecdc5289afec1af98640b6375a52aaf448fe7388
DIFF: https://github.com/llvm/llvm-project/commit/ecdc5289afec1af98640b6375a52aaf448fe7388.diff

LOG: [Clang] Fix crash in __builtin_assume_aligned (#114217)

The CodeGen for __builtin_assume_aligned assumes that the first argument
is a pointer, so crashes if the int-conversion error is downgraded or
disabled. Emit a non-downgradable error if the argument is not a
pointer, like we currently do for __builtin_launder.

Fixes #110914.

Added: 
    clang/test/Sema/builtin-assume-aligned-downgrade.c

Modified: 
    clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/pro-type-vararg.cpp
    clang/include/clang/Basic/DiagnosticSemaKinds.td
    clang/lib/Sema/SemaChecking.cpp
    clang/test/Sema/builtin-assume-aligned.c

Removed: 
    


################################################################################
diff  --git a/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/pro-type-vararg.cpp b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/pro-type-vararg.cpp
index 6792c7920dd112..3f73d1de333f48 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/pro-type-vararg.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/pro-type-vararg.cpp
@@ -51,8 +51,8 @@ void my_printf(const char* format, ...) {
 
 int my_vprintf(const char* format, va_list arg ); // OK to declare function taking va_list
 
-void ignoredBuiltinsTest() {
-  (void)__builtin_assume_aligned(0, 8);
+void ignoredBuiltinsTest(void *ptr) {
+  (void)__builtin_assume_aligned(ptr, 8);
   (void)__builtin_constant_p(0);
   (void)__builtin_fpclassify(0, 0, 0, 0, 0, 0.f);
   (void)__builtin_isinf_sign(0.f);

diff  --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 7bd154e7da2f4c..de34bcbf9ad4a6 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -12324,6 +12324,8 @@ def warn_noderef_to_dereferenceable_pointer : Warning<
 def err_builtin_launder_invalid_arg : Error<
   "%select{non-pointer|function pointer|void pointer}0 argument to "
   "'__builtin_launder' is not allowed">;
+def err_builtin_assume_aligned_invalid_arg : Error<
+  "non-pointer argument to '__builtin_assume_aligned' is not allowed">;
 
 def err_builtin_is_within_lifetime_invalid_arg : Error<
   "%select{non-|function }0pointer argument to '__builtin_is_within_lifetime' "

diff  --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 324ed7f6d90b75..be5d3694aec152 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -5341,9 +5341,11 @@ bool Sema::BuiltinAssumeAligned(CallExpr *TheCall) {
   {
     ExprResult FirstArgResult =
         DefaultFunctionArrayLvalueConversion(FirstArg);
-    if (checkBuiltinArgument(*this, TheCall, 0))
+    if (!FirstArgResult.get()->getType()->isPointerType()) {
+      Diag(TheCall->getBeginLoc(), diag::err_builtin_assume_aligned_invalid_arg)
+          << TheCall->getSourceRange();
       return true;
-    /// In-place updation of FirstArg by checkBuiltinArgument is ignored.
+    }
     TheCall->setArg(0, FirstArgResult.get());
   }
 

diff  --git a/clang/test/Sema/builtin-assume-aligned-downgrade.c b/clang/test/Sema/builtin-assume-aligned-downgrade.c
new file mode 100644
index 00000000000000..93631e73643737
--- /dev/null
+++ b/clang/test/Sema/builtin-assume-aligned-downgrade.c
@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 -fsyntax-only -Wno-int-conversion -triple x86_64-linux -verify %s
+
+// Check that the pointer->int conversion error is not downgradable for the
+// pointer argument to __builtin_assume_aligned.
+
+int test(int *a, int b) {
+  a = (int *)__builtin_assume_aligned(b, 32); // expected-error {{non-pointer argument to '__builtin_assume_aligned' is not allowed}}
+  int *y = __builtin_assume_aligned(1, 1); // expected-error {{non-pointer argument to '__builtin_assume_aligned' is not allowed}}
+}

diff  --git a/clang/test/Sema/builtin-assume-aligned.c b/clang/test/Sema/builtin-assume-aligned.c
index 33e85578451529..57378a3426524a 100644
--- a/clang/test/Sema/builtin-assume-aligned.c
+++ b/clang/test/Sema/builtin-assume-aligned.c
@@ -74,7 +74,7 @@ int test13(int *a) {
 }
 
 int test14(int *a, int b) {
-  a = (int *)__builtin_assume_aligned(b, 32); // expected-error {{incompatible integer to pointer conversion passing 'int' to parameter of type 'const void *}}
+  a = (int *)__builtin_assume_aligned(b, 32); // expected-error {{non-pointer argument to '__builtin_assume_aligned' is not allowed}}
 }
 
 int test15(int *b) {