[clang] [Clang] [Frontend] fix crash on parsing ternary operator with `vector_size` condition (PR #102004)

[Pavel Skripkin via cfe-commits]

https://github.com/pskrgag created https://github.com/llvm/llvm-project/pull/102004

Fix clang crash on parsing ternary operator with incompatible or pointer types as result.

Closes: #101718

>From 37f21a6fc5c69232c26b99659178b767c29a0107 Mon Sep 17 00:00:00 2001
From: Pavel Skripkin <paskripkin at gmail.com>
Date: Mon, 5 Aug 2024 17:23:03 +0300
Subject: [PATCH 1/2] clang/sema: fix crash on parsing unvalid ternary with
 vector guard

---
 clang/include/clang/Basic/DiagnosticSemaKinds.td |  2 ++
 clang/lib/Sema/SemaExprCXX.cpp                   | 10 ++++++++++
 2 files changed, 12 insertions(+)

diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 581434d33c5c9..848c5ffda4ea5 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -8187,6 +8187,8 @@ def err_conditional_vector_has_void : Error<
   "GNU vector conditional operand cannot be %select{void|a throw expression}0">;
 def err_conditional_vector_operand_type
     : Error<"enumeration type %0 is not allowed in a vector conditional">;
+def err_conditional_vector_result_pointer_type
+    : Error<"pointer type %0 is not allowed in a vector conditional">;
 def err_conditional_vector_cond_result_mismatch
     : Error<"cannot mix vectors and extended vectors in a vector conditional">;
 def err_conditional_vector_mismatched
diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
index 1b56b4cabd133..a43fc36fa8047 100644
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -6719,6 +6719,16 @@ QualType Sema::CheckVectorConditionalTypes(ExprResult &Cond, ExprResult &LHS,
             : UsualArithmeticConversions(LHS, RHS, QuestionLoc,
                                          ACK_Conditional);
 
+    if (ResultElementTy.isNull()) {
+      Diag(QuestionLoc, diag::err_conditional_vector_mismatched)
+          << LHSType << RHSType;
+      return {};
+    }
+    if (ResultElementTy->isPointerType()) {
+      Diag(QuestionLoc, diag::err_conditional_vector_result_pointer_type)
+          << ResultElementTy;
+      return {};
+    }
     if (ResultElementTy->isEnumeralType()) {
       Diag(QuestionLoc, diag::err_conditional_vector_operand_type)
           << ResultElementTy;

>From 2303adbd5ede11839b5e10e98f8c0725036685cf Mon Sep 17 00:00:00 2001
From: Pavel Skripkin <paskripkin at gmail.com>
Date: Mon, 5 Aug 2024 18:22:29 +0300
Subject: [PATCH 2/2] clang/test/SemaCXX: add test cases for unexpected ternary
 arms with vector guard

---
 clang/test/SemaCXX/vector-size-conditional.cpp | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/clang/test/SemaCXX/vector-size-conditional.cpp b/clang/test/SemaCXX/vector-size-conditional.cpp
index afed1cdeec087..51a22504a0d33 100644
--- a/clang/test/SemaCXX/vector-size-conditional.cpp
+++ b/clang/test/SemaCXX/vector-size-conditional.cpp
@@ -110,6 +110,10 @@ void Operands() {
   (void)(four_shorts ? four_shorts : uss); // expected-error {{cannot convert between scalar type 'unsigned short' and vector type 'FourShorts'}}
   (void)(four_ints ? four_floats : us);    // expected-error {{cannot convert between scalar type 'unsigned int' and vector type 'FourFloats'}}
   (void)(four_ints ? four_floats : sint);  // expected-error {{cannot convert between scalar type 'int' and vector type 'FourFloats'}}
+  (void)(four_ints ? &four_floats : &sint);  // expected-error {{vector operands to the vector conditional must be the same type ('FourFloats *' and 'int *')}}
+  (void)(four_ints ? &four_ints : &four_ints);  // expected-error {{pointer type 'FourInts *' is not allowed in a vector conditional}}
+  (void)(four_ints ? 0 : &four_ints);  // expected-error {{vector operands to the vector conditional must be the same type ('int' and 'FourInts *')}}
+  (void)(four_ints ? &four_ints: 0);  // expected-error {{vector operands to the vector conditional must be the same type ('FourInts *' and 'int')}}
 }
 
 template <typename T1, typename T2>
@@ -169,10 +173,10 @@ void all_dependent(Cond C, LHS L, RHS R) {
 void Templates() {
   dependent_cond(two_ints);
   dependent_operand(two_floats);
-  // expected-error at 165 {{vector operands to the vector conditional must be the same type ('__attribute__((__vector_size__(4 * sizeof(unsigned int)))) unsigned int' (vector of 4 'unsigned int' values) and '__attribute__((__vector_size__(4 * sizeof(double)))) double' (vector of 4 'double' values))}}}
+  // expected-error at 169 {{vector operands to the vector conditional must be the same type ('__attribute__((__vector_size__(4 * sizeof(unsigned int)))) unsigned int' (vector of 4 'unsigned int' values) and '__attribute__((__vector_size__(4 * sizeof(double)))) double' (vector of 4 'double' values))}}}
   all_dependent(four_ints, four_uints, four_doubles); // expected-note {{in instantiation of}}
 
-  // expected-error at 165 {{vector operands to the vector conditional must be the same type ('__attribute__((__vector_size__(4 * sizeof(unsigned int)))) unsigned int' (vector of 4 'unsigned int' values) and '__attribute__((__vector_size__(2 * sizeof(unsigned int)))) unsigned int' (vector of 2 'unsigned int' values))}}}
+  // expected-error at 169 {{vector operands to the vector conditional must be the same type ('__attribute__((__vector_size__(4 * sizeof(unsigned int)))) unsigned int' (vector of 4 'unsigned int' values) and '__attribute__((__vector_size__(2 * sizeof(unsigned int)))) unsigned int' (vector of 2 'unsigned int' values))}}}
   all_dependent(four_ints, four_uints, two_uints); // expected-note {{in instantiation of}}
   all_dependent(four_ints, four_uints, four_uints);
 }