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[clang][bytecode] Check memove/memcpy for available elements (#121383)

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Both destination and source pointer need to have at least as many
elements as requested.
This commit is contained in:
Timm Baeder 2024-12-31 12:14:27 +01:00 committed by GitHub
parent b35d3453dd
commit f0d60170cc
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GPG Key ID: B5690EEEBB952194
2 changed files with 47 additions and 15 deletions
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53
clang/lib/AST/ByteCode/InterpBuiltin.cpp
View File

@ -17,6 +17,7 @@
#include "clang/Basic/Builtins.h"
#include "clang/Basic/TargetBuiltins.h"
#include "clang/Basic/TargetInfo.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Support/SipHash.h"
namespace clang {
@ -1837,6 +1838,7 @@ static bool interp__builtin_memcpy(InterpState &S, CodePtr OpPC,
assert(Call->getNumArgs() == 3);
unsigned ID = Func->getBuiltinID();
Pointer DestPtr = getParam<Pointer>(Frame, 0);
const ASTContext &ASTCtx = S.getASTContext();
const Pointer &SrcPtr = getParam<Pointer>(Frame, 1);
const APSInt &Size =
peekToAPSInt(S.Stk, *S.getContext().classify(Call->getArg(2)));
@ -1857,34 +1859,55 @@ static bool interp__builtin_memcpy(InterpState &S, CodePtr OpPC,
Pointer DiagPtr = (SrcPtr.isZero() ? SrcPtr : DestPtr);
S.FFDiag(S.Current->getSource(OpPC), diag::note_constexpr_memcpy_null)
<< /*IsMove=*/Move << /*IsWchar=*/false << !SrcPtr.isZero()
<< DiagPtr.toDiagnosticString(S.getASTContext());
<< DiagPtr.toDiagnosticString(ASTCtx);
return false;
}
QualType ElemType;
if (DestPtr.getFieldDesc()->isArray())
ElemType = DestPtr.getFieldDesc()->getElemQualType();
else
ElemType = DestPtr.getType();
QualType DestElemType;
size_t RemainingDestElems;
if (DestPtr.getFieldDesc()->isArray()) {
DestElemType = DestPtr.getFieldDesc()->getElemQualType();
RemainingDestElems = (DestPtr.getNumElems() - DestPtr.getIndex());
} else {
DestElemType = DestPtr.getType();
RemainingDestElems = 1;
}
unsigned DestElemSize = ASTCtx.getTypeSizeInChars(DestElemType).getQuantity();
unsigned ElemSize =
S.getASTContext().getTypeSizeInChars(ElemType).getQuantity();
if (Size.urem(ElemSize) != 0) {
if (Size.urem(DestElemSize) != 0) {
S.FFDiag(S.Current->getSource(OpPC),
diag::note_constexpr_memcpy_unsupported)
<< Move << /*IsWchar=*/false << 0 << ElemType << Size << ElemSize;
<< Move << /*IsWchar=*/false << 0 << DestElemType << Size
<< DestElemSize;
return false;
}
QualType SrcElemType;
if (SrcPtr.getFieldDesc()->isArray())
size_t RemainingSrcElems;
if (SrcPtr.getFieldDesc()->isArray()) {
SrcElemType = SrcPtr.getFieldDesc()->getElemQualType();
else
RemainingSrcElems = (SrcPtr.getNumElems() - SrcPtr.getIndex());
} else {
SrcElemType = SrcPtr.getType();
RemainingSrcElems = 1;
}
unsigned SrcElemSize = ASTCtx.getTypeSizeInChars(SrcElemType).getQuantity();
if (!S.getASTContext().hasSameUnqualifiedType(ElemType, SrcElemType)) {
if (!ASTCtx.hasSameUnqualifiedType(DestElemType, SrcElemType)) {
S.FFDiag(S.Current->getSource(OpPC), diag::note_constexpr_memcpy_type_pun)
<< Move << SrcElemType << ElemType;
<< Move << SrcElemType << DestElemType;
return false;
}
// Check if we have enough elements to read from and write to/
size_t RemainingDestBytes = RemainingDestElems * DestElemSize;
size_t RemainingSrcBytes = RemainingSrcElems * SrcElemSize;
if (Size.ugt(RemainingDestBytes) || Size.ugt(RemainingSrcBytes)) {
APInt N = Size.udiv(DestElemSize);
S.FFDiag(S.Current->getSource(OpPC),
diag::note_constexpr_memcpy_unsupported)
<< Move << /*IsWChar*/ false << (Size.ugt(RemainingSrcBytes) ? 1 : 2)
<< DestElemType << toString(N, 10, /*Signed=*/false);
return false;
}
@ -1905,7 +1928,7 @@ static bool interp__builtin_memcpy(InterpState &S, CodePtr OpPC,
// As a last resort, reject dummy pointers.
if (DestPtr.isDummy() || SrcPtr.isDummy())
return false;
assert(Size.getZExtValue() % ElemSize == 0);
assert(Size.getZExtValue() % DestElemSize == 0);
if (!DoMemcpy(S, OpPC, SrcPtr, DestPtr, Bytes(Size.getZExtValue()).toBits()))
return false;

9
clang/test/AST/ByteCode/builtin-functions.cpp
View File

@ -1244,6 +1244,15 @@ namespace BuiltinMemcpy {
}
static_assert(cpyptr());
#ifndef __AVR__
constexpr int test_memmove(int a, int b, int n) {
int arr[4] = {1, 2, 3, 4};
__builtin_memmove(arr + a, arr + b, n); // both-note {{destination is not a contiguous array of at least 3 elements of type 'int'}}
return result(arr);
}
static_assert(test_memmove(2, 0, 12) == 4234); // both-error {{constant}} \
// both-note {{in call}}
#endif
}
namespace Memcmp {