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[clang][bytecode] Only allow lossless ptr-to-int casts (#111669)

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Only allow those casts if the bitwidth of the two types match.
This commit is contained in:
Timm Baeder 2024-10-09 17:13:22 +02:00 committed by GitHub
parent 1731bb79a9
commit e637a5c9fe
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GPG Key ID: B5690EEEBB952194
3 changed files with 51 additions and 37 deletions
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41
clang/lib/AST/ByteCode/Interp.cpp
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@ -22,6 +22,7 @@
#include "clang/AST/Expr.h"
#include "clang/AST/ExprCXX.h"
#include "clang/Basic/DiagnosticSema.h"
#include "clang/Basic/TargetInfo.h"
#include "llvm/ADT/APSInt.h"
#include "llvm/ADT/StringExtras.h"
#include <limits>
@ -1415,6 +1416,46 @@ bool InvalidShuffleVectorIndex(InterpState &S, CodePtr OpPC, uint32_t Index) {
return false;
}
bool CheckPointerToIntegralCast(InterpState &S, CodePtr OpPC,
const Pointer &Ptr, unsigned BitWidth) {
if (Ptr.isDummy())
return false;
const SourceInfo &E = S.Current->getSource(OpPC);
S.CCEDiag(E, diag::note_constexpr_invalid_cast)
<< 2 << S.getLangOpts().CPlusPlus << S.Current->getRange(OpPC);
if (Ptr.isBlockPointer() && !Ptr.isZero()) {
// Only allow based lvalue casts if they are lossless.
if (S.getASTContext().getTargetInfo().getPointerWidth(LangAS::Default) !=
BitWidth)
return Invalid(S, OpPC);
}
return true;
}
bool CastPointerIntegralAP(InterpState &S, CodePtr OpPC, uint32_t BitWidth) {
const Pointer &Ptr = S.Stk.pop<Pointer>();
if (!CheckPointerToIntegralCast(S, OpPC, Ptr, BitWidth))
return false;
S.Stk.push<IntegralAP<false>>(
IntegralAP<false>::from(Ptr.getIntegerRepresentation(), BitWidth));
return true;
}
bool CastPointerIntegralAPS(InterpState &S, CodePtr OpPC, uint32_t BitWidth) {
const Pointer &Ptr = S.Stk.pop<Pointer>();
if (!CheckPointerToIntegralCast(S, OpPC, Ptr, BitWidth))
return false;
S.Stk.push<IntegralAP<true>>(
IntegralAP<true>::from(Ptr.getIntegerRepresentation(), BitWidth));
return true;
}
// https://github.com/llvm/llvm-project/issues/102513
#if defined(_WIN32) && !defined(__clang__) && !defined(NDEBUG)
#pragma optimize("", off)

43
clang/lib/AST/ByteCode/Interp.h
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@ -2289,53 +2289,22 @@ static inline bool CastFloatingIntegralAPS(InterpState &S, CodePtr OpPC,
return CheckFloatResult(S, OpPC, F, Status, FPO);
}
bool CheckPointerToIntegralCast(InterpState &S, CodePtr OpPC,
const Pointer &Ptr, unsigned BitWidth);
bool CastPointerIntegralAP(InterpState &S, CodePtr OpPC, uint32_t BitWidth);
bool CastPointerIntegralAPS(InterpState &S, CodePtr OpPC, uint32_t BitWidth);
template <PrimType Name, class T = typename PrimConv<Name>::T>
bool CastPointerIntegral(InterpState &S, CodePtr OpPC) {
const Pointer &Ptr = S.Stk.pop<Pointer>();
if (Ptr.isDummy())
if (!CheckPointerToIntegralCast(S, OpPC, Ptr, T::bitWidth()))
return false;
const SourceInfo &E = S.Current->getSource(OpPC);
S.CCEDiag(E, diag::note_constexpr_invalid_cast)
<< 2 << S.getLangOpts().CPlusPlus << S.Current->getRange(OpPC);
S.Stk.push<T>(T::from(Ptr.getIntegerRepresentation()));
return true;
}
static inline bool CastPointerIntegralAP(InterpState &S, CodePtr OpPC,
uint32_t BitWidth) {
const Pointer &Ptr = S.Stk.pop<Pointer>();
if (Ptr.isDummy())
return false;
const SourceInfo &E = S.Current->getSource(OpPC);
S.CCEDiag(E, diag::note_constexpr_invalid_cast)
<< 2 << S.getLangOpts().CPlusPlus << S.Current->getRange(OpPC);
S.Stk.push<IntegralAP<false>>(
IntegralAP<false>::from(Ptr.getIntegerRepresentation(), BitWidth));
return true;
}
static inline bool CastPointerIntegralAPS(InterpState &S, CodePtr OpPC,
uint32_t BitWidth) {
const Pointer &Ptr = S.Stk.pop<Pointer>();
if (Ptr.isDummy())
return false;
const SourceInfo &E = S.Current->getSource(OpPC);
S.CCEDiag(E, diag::note_constexpr_invalid_cast)
<< 2 << S.getLangOpts().CPlusPlus << S.Current->getRange(OpPC);
S.Stk.push<IntegralAP<true>>(
IntegralAP<true>::from(Ptr.getIntegerRepresentation(), BitWidth));
return true;
}
template <PrimType Name, class T = typename PrimConv<Name>::T>
static inline bool CastIntegralFixedPoint(InterpState &S, CodePtr OpPC,
uint32_t FPS) {

4
clang/test/AST/ByteCode/codegen.cpp
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@ -1,6 +1,10 @@
// RUN: %clang_cc1 -triple x86_64-linux -emit-llvm -o - %s | FileCheck %s
// RUN: %clang_cc1 -triple x86_64-linux -emit-llvm -o - %s -fexperimental-new-constant-interpreter | FileCheck %s
#ifdef __SIZEOF_INT128__
// CHECK: @PR11705 = global i128 0
__int128_t PR11705 = (__int128_t)&PR11705;
#endif
int arr[2];
// CHECK: @pastEnd = constant ptr getelementptr (i8, ptr @arr, i64 8)