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When the new expr's array size is an ICE, emit it as a constant expression. 

This bypasses integer sanitization checks which are redundant on the expression since it's been checked by Sema. Fixes a clang codegen assertion on "void test() { new int[0+1]{0}; }" when building with -fsanitize=signed-integer-overflow.

llvm-svn: 295006
This commit is contained in:
Nick Lewycky 2017-02-13 23:49:55 +00:00
parent 47a8b6829c
commit 0752762180
2 changed files with 11 additions and 1 deletions
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5
clang/lib/CodeGen/CGExprCXX.cpp
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@ -659,7 +659,10 @@ static llvm::Value *EmitCXXNewAllocSize(CodeGenFunction &CGF,
// Emit the array size expression.
// We multiply the size of all dimensions for NumElements.
// e.g for 'int[2][3]', ElemType is 'int' and NumElements is 6.
numElements = CGF.EmitScalarExpr(e->getArraySize());
numElements = CGF.CGM.EmitConstantExpr(e->getArraySize(),
CGF.getContext().getSizeType(), &CGF);
if (!numElements)
numElements = CGF.EmitScalarExpr(e->getArraySize());
assert(isa<llvm::IntegerType>(numElements->getType()));
// The number of elements can be have an arbitrary integer type;

7
clang/test/CodeGenCXX/new-array-init.cpp
View File

@ -1,4 +1,5 @@
// RUN: %clang_cc1 -std=c++11 -triple i386-unknown-unknown %s -emit-llvm -o - | FileCheck %s
// RUN: %clang_cc1 -std=c++11 -triple i386-unknown-unknown %s -emit-llvm -fsanitize=signed-integer-overflow -o - | FileCheck --check-prefix=SIO %s
// CHECK: @[[ABC4:.*]] = {{.*}} constant [4 x i8] c"abc\00"
// CHECK: @[[ABC15:.*]] = {{.*}} constant [15 x i8] c"abc\00\00\00\00
@ -116,3 +117,9 @@ void aggr_sufficient(int n) {
struct Aggr { int a, b; };
new Aggr[n] { 1, 2, 3 };
}
// SIO-LABEL: define void @_Z14constexpr_testv
void constexpr_test() {
// SIO: call i8* @_Zna{{.}}(i32 4)
new int[0+1]{0};
}