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[clang] Fix crash during template sema checking 

Summary: If the size parameter of `__builtin_memcpy_inline` comes from an un-instantiated template parameter current code would crash.

Reviewers: efriedma, courbet

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D76504
This commit is contained in:
Guillaume Chatelet 2020-03-20 16:23:49 +01:00
parent f9a8650578
commit d260a10d98
2 changed files with 15 additions and 4 deletions
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13
clang/lib/Sema/SemaChecking.cpp
View File

@ -1649,11 +1649,16 @@ Sema::CheckBuiltinFunctionCall(FunctionDecl *FDecl, unsigned BuiltinID,
case Builtin::BI__builtin_nontemporal_store:
return SemaBuiltinNontemporalOverloaded(TheCallResult);
case Builtin::BI__builtin_memcpy_inline: {
// __builtin_memcpy_inline size argument is a constant by definition.
if (TheCall->getArg(2)->EvaluateKnownConstInt(Context).isNullValue())
clang::Expr *SizeOp = TheCall->getArg(2);
// We warn about copying to or from `nullptr` pointers when `size` is
// greater than 0. When `size` is value dependent we cannot evaluate its
// value so we bail out.
if (SizeOp->isValueDependent())
break;
CheckNonNullArgument(*this, TheCall->getArg(0), TheCall->getExprLoc());
CheckNonNullArgument(*this, TheCall->getArg(1), TheCall->getExprLoc());
if (!SizeOp->EvaluateKnownConstInt(Context).isNullValue()) {
CheckNonNullArgument(*this, TheCall->getArg(0), TheCall->getExprLoc());
CheckNonNullArgument(*this, TheCall->getArg(1), TheCall->getExprLoc());
}
break;
}
#define BUILTIN(ID, TYPE, ATTRS)

6
clang/test/Sema/builtins-memcpy-inline.c → clang/test/Sema/builtins-memcpy-inline.cpp
View File

@ -30,3 +30,9 @@ void test_memcpy_inline_null_buffer_is_ok_if_size_is_zero(void *ptr) {
void test_memcpy_inline_non_constant_size(void *dst, const void *src, unsigned size) {
__builtin_memcpy_inline(dst, src, size); // expected-error {{argument to '__builtin_memcpy_inline' must be a constant integer}}
}
template <unsigned size>
void test_memcpy_inline_template(void *dst, const void *src) {
// we do not try to evaluate size in non intantiated templates.
__builtin_memcpy_inline(dst, src, size);
}