[clang] 606a734 - [PR47636] Fix tryEmitPrivate to handle non-constantarraytypes

[Erich Keane via cfe-commits]

Author: Erich Keane
Date: 2020-09-24T12:09:22-07:00
New Revision: 606a734755d1fb6c35a17680d0c251f834b79334

URL: https://github.com/llvm/llvm-project/commit/606a734755d1fb6c35a17680d0c251f834b79334
DIFF: https://github.com/llvm/llvm-project/commit/606a734755d1fb6c35a17680d0c251f834b79334.diff

LOG: [PR47636] Fix tryEmitPrivate to handle non-constantarraytypes

As mentioned in the bug report, tryEmitPrivate chokes on the
MaterializeTemporaryExpr in the reproducers, since it assumes that if
there are elements, than it must be a ConstantArrayType. However, the
MaterializeTemporaryExpr (which matches exactly the AST when it is NOT a
global/static) has an incomplete array type.

This changes the section where the number-of-elements is non-zero to
properly handle non-CAT types by just extracting it as an array type
(since all we needed was the element type out of it).

Added: 
    clang/test/CodeGenCXX/pr47636.cpp

Modified: 
    clang/lib/CodeGen/CGExprConstant.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/CodeGen/CGExprConstant.cpp b/clang/lib/CodeGen/CGExprConstant.cpp
index c6b2930faece..5b3631087f45 100644
--- a/clang/lib/CodeGen/CGExprConstant.cpp
+++ b/clang/lib/CodeGen/CGExprConstant.cpp
@@ -2108,8 +2108,7 @@ llvm::Constant *ConstantEmitter::tryEmitPrivate(const APValue &Value,
   case APValue::Union:
     return ConstStructBuilder::BuildStruct(*this, Value, DestType);
   case APValue::Array: {
-    const ConstantArrayType *CAT =
-        CGM.getContext().getAsConstantArrayType(DestType);
+    const ArrayType *ArrayTy = CGM.getContext().getAsArrayType(DestType);
     unsigned NumElements = Value.getArraySize();
     unsigned NumInitElts = Value.getArrayInitializedElts();
 
@@ -2117,7 +2116,7 @@ llvm::Constant *ConstantEmitter::tryEmitPrivate(const APValue &Value,
     llvm::Constant *Filler = nullptr;
     if (Value.hasArrayFiller()) {
       Filler = tryEmitAbstractForMemory(Value.getArrayFiller(),
-                                        CAT->getElementType());
+                                        ArrayTy->getElementType());
       if (!Filler)
         return nullptr;
     }
@@ -2132,7 +2131,7 @@ llvm::Constant *ConstantEmitter::tryEmitPrivate(const APValue &Value,
     llvm::Type *CommonElementType = nullptr;
     for (unsigned I = 0; I < NumInitElts; ++I) {
       llvm::Constant *C = tryEmitPrivateForMemory(
-          Value.getArrayInitializedElt(I), CAT->getElementType());
+          Value.getArrayInitializedElt(I), ArrayTy->getElementType());
       if (!C) return nullptr;
 
       if (I == 0)
@@ -2144,11 +2143,10 @@ llvm::Constant *ConstantEmitter::tryEmitPrivate(const APValue &Value,
 
     // This means that the array type is probably "IncompleteType" or some
     // type that is not ConstantArray.
-    if (CAT == nullptr && CommonElementType == nullptr && !NumInitElts) {
-      const ArrayType *AT = CGM.getContext().getAsArrayType(DestType);
-      CommonElementType = CGM.getTypes().ConvertType(AT->getElementType());
-      llvm::ArrayType *AType = llvm::ArrayType::get(CommonElementType,
-                                                    NumElements);
+    if (!Filler && !NumInitElts) {
+      CommonElementType = CGM.getTypes().ConvertType(ArrayTy->getElementType());
+      llvm::ArrayType *AType =
+          llvm::ArrayType::get(CommonElementType, NumElements);
       return llvm::ConstantAggregateZero::get(AType);
     }
 

diff  --git a/clang/test/CodeGenCXX/pr47636.cpp b/clang/test/CodeGenCXX/pr47636.cpp
new file mode 100644
index 000000000000..ac64400e1daa
--- /dev/null
+++ b/clang/test/CodeGenCXX/pr47636.cpp
@@ -0,0 +1,10 @@
+// RUN: %clang_cc1 -o - -emit-llvm -triple x86_64-linux-pc %s | FileCheck %s
+int(&&intu_rvref)[] {1,2,3,4};
+// CHECK: @_ZGR10intu_rvref_ = internal global [4 x i32] [i32 1, i32 2, i32 3, i32 4]
+// CHECK: @intu_rvref = constant [4 x i32]* @_ZGR10intu_rvref_
+
+void foo() {
+  static const int(&&intu_rvref)[] {1,2,3,4};
+  // CHECK: @_ZZ3foovE10intu_rvref = internal constant [4 x i32]* @_ZGRZ3foovE10intu_rvref_
+  // CHECK: @_ZGRZ3foovE10intu_rvref_ = internal constant [4 x i32] [i32 1, i32 2, i32 3, i32 4]
+}