[clang] [clang][bytecode] Handle bitcasts involving bitfields (PR #116843)
Timm Baeder via cfe-commits
cfe-commits at lists.llvm.org
Wed Nov 20 01:42:59 PST 2024
https://github.com/tbaederr updated https://github.com/llvm/llvm-project/pull/116843
>From 95c8d0346a83d7137209dde6fb5b61436d210ee2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timm=20B=C3=A4der?= <tbaeder at redhat.com>
Date: Fri, 8 Nov 2024 14:37:56 +0100
Subject: [PATCH] [clang][bytecode] Handle bitcasts involving bitfields
---
clang/lib/AST/ByteCode/BitcastBuffer.cpp | 88 ++++
clang/lib/AST/ByteCode/BitcastBuffer.h | 66 +++
clang/lib/AST/ByteCode/Boolean.h | 4 +-
clang/lib/AST/ByteCode/Integral.h | 1 +
.../lib/AST/ByteCode/InterpBuiltinBitCast.cpp | 251 ++++------
clang/lib/AST/CMakeLists.txt | 1 +
.../ByteCode/builtin-bit-cast-bitfields.cpp | 437 ++++++++++++++++++
clang/test/AST/ByteCode/builtin-bit-cast.cpp | 104 +----
.../unittests/AST/ByteCode/BitcastBuffer.cpp | 83 ++++
clang/unittests/AST/ByteCode/CMakeLists.txt | 1 +
10 files changed, 790 insertions(+), 246 deletions(-)
create mode 100644 clang/lib/AST/ByteCode/BitcastBuffer.cpp
create mode 100644 clang/lib/AST/ByteCode/BitcastBuffer.h
create mode 100644 clang/test/AST/ByteCode/builtin-bit-cast-bitfields.cpp
create mode 100644 clang/unittests/AST/ByteCode/BitcastBuffer.cpp
diff --git a/clang/lib/AST/ByteCode/BitcastBuffer.cpp b/clang/lib/AST/ByteCode/BitcastBuffer.cpp
new file mode 100644
index 00000000000000..093f2b2c224093
--- /dev/null
+++ b/clang/lib/AST/ByteCode/BitcastBuffer.cpp
@@ -0,0 +1,88 @@
+//===-------------------- Bitcastbuffer.cpp ---------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#include "BitcastBuffer.h"
+
+using namespace clang;
+using namespace clang::interp;
+
+void BitcastBuffer::pushData(const std::byte *In, size_t BitOffset,
+ size_t BitWidth, Endian TargetEndianness) {
+ for (unsigned It = 0; It != BitWidth; ++It) {
+ bool BitValue = bitof(In, It);
+ if (!BitValue)
+ continue;
+
+ unsigned DstBit;
+ if (TargetEndianness == Endian::Little)
+ DstBit = BitOffset + It;
+ else
+ DstBit = size() - BitOffset - BitWidth + It;
+
+ unsigned DstByte = (DstBit / 8);
+ Data[DstByte] |= std::byte{1} << (DstBit % 8);
+ }
+}
+
+std::unique_ptr<std::byte[]>
+BitcastBuffer::copyBits(unsigned BitOffset, unsigned BitWidth,
+ unsigned FullBitWidth, Endian TargetEndianness) const {
+ assert(BitWidth <= FullBitWidth);
+ assert(fullByte(FullBitWidth));
+ auto Out = std::make_unique<std::byte[]>(FullBitWidth / 8);
+
+ for (unsigned It = 0; It != BitWidth; ++It) {
+ unsigned BitIndex;
+ if (TargetEndianness == Endian::Little)
+ BitIndex = BitOffset + It;
+ else
+ BitIndex = size() - BitWidth - BitOffset + It;
+
+ bool BitValue = bitof(Data.get(), BitIndex);
+ if (!BitValue)
+ continue;
+ unsigned DstBit = It;
+ unsigned DstByte = (DstBit / 8);
+ Out[DstByte] |= std::byte{1} << (DstBit % 8);
+ }
+
+ return Out;
+}
+
+#if 0
+ template<typename T>
+ static std::string hex(T t) {
+ std::stringstream stream;
+ stream << std::hex << (int)t;
+ return std::string(stream.str());
+ }
+
+
+ void BitcastBuffer::dump(bool AsHex = true) const {
+ llvm::errs() << "LSB\n ";
+ unsigned LineLength = 0;
+ for (unsigned I = 0; I != (FinalBitSize / 8); ++I) {
+ std::byte B = Data[I];
+ if (AsHex) {
+ std::stringstream stream;
+ stream << std::hex << (int)B;
+ llvm::errs() << stream.str();
+ LineLength += stream.str().size() + 1;
+ } else {
+ llvm::errs() << std::bitset<8>((int)B).to_string();
+ LineLength += 8 + 1;
+ // llvm::errs() << (int)B;
+ }
+ llvm::errs() << ' ';
+ }
+ llvm::errs() << '\n';
+
+ for (unsigned I = 0; I != LineLength; ++I)
+ llvm::errs() << ' ';
+ llvm::errs() << "MSB\n";
+ }
+#endif
diff --git a/clang/lib/AST/ByteCode/BitcastBuffer.h b/clang/lib/AST/ByteCode/BitcastBuffer.h
new file mode 100644
index 00000000000000..ca4716b573618a
--- /dev/null
+++ b/clang/lib/AST/ByteCode/BitcastBuffer.h
@@ -0,0 +1,66 @@
+//===--------------------- BitcastBuffer.h ----------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#ifndef LLVM_CLANG_AST_INTERP_BITCAST_BUFFER_H
+#define LLVM_CLANG_AST_INTERP_BITCAST_BUFFER_H
+
+#include <cassert>
+#include <cstddef>
+#include <memory>
+
+namespace clang {
+namespace interp {
+
+enum class Endian { Little, Big };
+
+/// Returns the value of the bit in the given sequence of bytes.
+static inline bool bitof(const std::byte *B, unsigned BitIndex) {
+ return (B[BitIndex / 8] & (std::byte{1} << (BitIndex % 8))) != std::byte{0};
+}
+
+/// Returns whether \p N is a full byte offset or size.
+static inline bool fullByte(unsigned N) { return N % 8 == 0; }
+
+/// Track what bits have been initialized to known values and which ones
+/// have indeterminate value.
+/// All offsets are in bits.
+struct BitcastBuffer {
+ size_t FinalBitSize = 0;
+ std::unique_ptr<std::byte[]> Data;
+
+ BitcastBuffer(size_t FinalBitSize) : FinalBitSize(FinalBitSize) {
+ assert(fullByte(FinalBitSize));
+ unsigned ByteSize = FinalBitSize / 8;
+ Data = std::make_unique<std::byte[]>(ByteSize);
+ }
+
+ /// Returns the buffer size in bits.
+ size_t size() const { return FinalBitSize; }
+
+ /// Returns \c true if all bits in the buffer have been initialized.
+ bool allInitialized() const {
+ // FIXME: Implement.
+ return true;
+ }
+
+ /// Push \p BitWidth bits at \p BitOffset from \p In into the buffer.
+ /// \p TargetEndianness is the endianness of the target we're compiling for.
+ /// \p In must hold at least \p BitWidth many bits.
+ void pushData(const std::byte *In, size_t BitOffset, size_t BitWidth,
+ Endian TargetEndianness);
+ /// Copy \p BitWidth bits at offset \p BitOffset from the buffer.
+ /// \p TargetEndianness is the endianness of the target we're compiling for.
+ ///
+ /// The returned output holds exactly (\p FullBitWidth / 8) bytes.
+ std::unique_ptr<std::byte[]> copyBits(unsigned BitOffset, unsigned BitWidth,
+ unsigned FullBitWidth,
+ Endian TargetEndianness) const;
+};
+
+} // namespace interp
+} // namespace clang
+#endif
diff --git a/clang/lib/AST/ByteCode/Boolean.h b/clang/lib/AST/ByteCode/Boolean.h
index 78d75e75c7531a..8380e85865ac55 100644
--- a/clang/lib/AST/ByteCode/Boolean.h
+++ b/clang/lib/AST/ByteCode/Boolean.h
@@ -82,9 +82,7 @@ class Boolean final {
Boolean truncate(unsigned TruncBits) const { return *this; }
static Boolean bitcastFromMemory(const std::byte *Buff, unsigned BitWidth) {
- // Boolean width is currently always 8 for all supported targets. If this
- // changes we need to get the bool width from the target info.
- assert(BitWidth == 8);
+ // Just load the first byte.
bool Val = static_cast<bool>(*Buff);
return Boolean(Val);
}
diff --git a/clang/lib/AST/ByteCode/Integral.h b/clang/lib/AST/ByteCode/Integral.h
index ca3674263aef4f..bb1688a8a7622c 100644
--- a/clang/lib/AST/ByteCode/Integral.h
+++ b/clang/lib/AST/ByteCode/Integral.h
@@ -181,6 +181,7 @@ template <unsigned Bits, bool Signed> class Integral final {
}
Integral truncate(unsigned TruncBits) const {
+ assert(TruncBits >= 1);
if (TruncBits >= Bits)
return *this;
const ReprT BitMask = (ReprT(1) << ReprT(TruncBits)) - 1;
diff --git a/clang/lib/AST/ByteCode/InterpBuiltinBitCast.cpp b/clang/lib/AST/ByteCode/InterpBuiltinBitCast.cpp
index 7e8853d3469317..1adfacdca3fa57 100644
--- a/clang/lib/AST/ByteCode/InterpBuiltinBitCast.cpp
+++ b/clang/lib/AST/ByteCode/InterpBuiltinBitCast.cpp
@@ -6,6 +6,7 @@
//
//===----------------------------------------------------------------------===//
#include "InterpBuiltinBitCast.h"
+#include "BitcastBuffer.h"
#include "Boolean.h"
#include "Context.h"
#include "Floating.h"
@@ -21,6 +22,16 @@
using namespace clang;
using namespace clang::interp;
+/// Implement __builtin_bit_cast and related operations.
+/// Since our internal representation for data is more complex than
+/// something we can simply memcpy or memcmp, we first bitcast all the data
+/// into a buffer, which we then later use to copy the data into the target.
+
+// TODO:
+// - Try to minimize heap allocations.
+// - Optimize the common case of only pushing and pulling full
+// bytes to/from the buffer.
+
/// Used to iterate over pointer fields.
using DataFunc = llvm::function_ref<bool(const Pointer &P, PrimType Ty,
size_t BitOffset, bool PackedBools)>;
@@ -61,81 +72,12 @@ using DataFunc = llvm::function_ref<bool(const Pointer &P, PrimType Ty,
} \
} while (0)
-static bool bitof(std::byte B, unsigned BitIndex) {
- return (B & (std::byte{1} << BitIndex)) != std::byte{0};
-}
-
static void swapBytes(std::byte *M, size_t N) {
for (size_t I = 0; I != (N / 2); ++I)
std::swap(M[I], M[N - 1 - I]);
}
-/// Track what bits have been initialized to known values and which ones
-/// have indeterminate value.
-/// All offsets are in bits.
-struct BitcastBuffer {
- size_t SizeInBits = 0;
- llvm::SmallVector<std::byte> Data;
-
- BitcastBuffer() = default;
-
- size_t size() const { return SizeInBits; }
-
- const std::byte *data() const { return Data.data(); }
-
- std::byte *getBytes(unsigned BitOffset) const {
- assert(BitOffset % 8 == 0);
- assert(BitOffset < SizeInBits);
- return const_cast<std::byte *>(data() + (BitOffset / 8));
- }
-
- bool allInitialized() const {
- // FIXME: Implement.
- return true;
- }
-
- bool atByteBoundary() const { return (Data.size() * 8) == SizeInBits; }
-
- void pushBit(bool Value) {
- if (atByteBoundary())
- Data.push_back(std::byte{0});
-
- if (Value)
- Data.back() |= (std::byte{1} << (SizeInBits % 8));
- ++SizeInBits;
- }
-
- void pushData(const std::byte *data, size_t BitWidth, bool BigEndianTarget) {
- bool OnlyFullBytes = BitWidth % 8 == 0;
- unsigned NBytes = BitWidth / 8;
-
- size_t BitsHandled = 0;
- // Read all full bytes first
- for (size_t I = 0; I != NBytes; ++I) {
- std::byte B =
- BigEndianTarget ? data[NBytes - OnlyFullBytes - I] : data[I];
- for (unsigned X = 0; X != 8; ++X) {
- pushBit(bitof(B, X));
- ++BitsHandled;
- }
- }
-
- if (BitsHandled == BitWidth)
- return;
-
- // Rest of the bits.
- assert((BitWidth - BitsHandled) < 8);
- std::byte B = BigEndianTarget ? data[0] : data[NBytes];
- for (size_t I = 0, E = (BitWidth - BitsHandled); I != E; ++I) {
- pushBit(bitof(B, I));
- ++BitsHandled;
- }
-
- assert(BitsHandled == BitWidth);
- }
-};
-
-/// We use this to recursively iterate over all fields and elemends of a pointer
+/// We use this to recursively iterate over all fields and elements of a pointer
/// and extract relevant data for a bitcast.
static bool enumerateData(const Pointer &P, const Context &Ctx, size_t Offset,
DataFunc F) {
@@ -144,33 +86,30 @@ static bool enumerateData(const Pointer &P, const Context &Ctx, size_t Offset,
// Primitives.
if (FieldDesc->isPrimitive())
- return F(P, FieldDesc->getPrimType(), Offset, false);
+ return F(P, FieldDesc->getPrimType(), Offset, /*PackedBools=*/false);
// Primitive arrays.
if (FieldDesc->isPrimitiveArray()) {
- bool BigEndianTarget = Ctx.getASTContext().getTargetInfo().isBigEndian();
QualType ElemType = FieldDesc->getElemQualType();
size_t ElemSizeInBits = Ctx.getASTContext().getTypeSize(ElemType);
PrimType ElemT = *Ctx.classify(ElemType);
// Special case, since the bools here are packed.
bool PackedBools = FieldDesc->getType()->isExtVectorBoolType();
+ unsigned NumElems = FieldDesc->getNumElems();
bool Ok = true;
- for (unsigned I = 0; I != FieldDesc->getNumElems(); ++I) {
- unsigned Index = BigEndianTarget ? (FieldDesc->getNumElems() - 1 - I) : I;
- Ok = Ok && F(P.atIndex(Index), ElemT, Offset, PackedBools);
- Offset += ElemSizeInBits;
+ for (unsigned I = 0; I != NumElems; ++I) {
+ Ok = Ok && F(P.atIndex(I), ElemT, Offset, PackedBools);
+ Offset += PackedBools ? 1 : ElemSizeInBits;
}
return Ok;
}
// Composite arrays.
if (FieldDesc->isCompositeArray()) {
- bool BigEndianTarget = Ctx.getASTContext().getTargetInfo().isBigEndian();
QualType ElemType = FieldDesc->getElemQualType();
size_t ElemSizeInBits = Ctx.getASTContext().getTypeSize(ElemType);
for (unsigned I = 0; I != FieldDesc->getNumElems(); ++I) {
- unsigned Index = BigEndianTarget ? (FieldDesc->getNumElems() - 1 - I) : I;
- enumerateData(P.atIndex(Index).narrow(), Ctx, Offset, F);
+ enumerateData(P.atIndex(I).narrow(), Ctx, Offset, F);
Offset += ElemSizeInBits;
}
return true;
@@ -178,39 +117,23 @@ static bool enumerateData(const Pointer &P, const Context &Ctx, size_t Offset,
// Records.
if (FieldDesc->isRecord()) {
- bool BigEndianTarget = Ctx.getASTContext().getTargetInfo().isBigEndian();
const Record *R = FieldDesc->ElemRecord;
const ASTRecordLayout &Layout =
Ctx.getASTContext().getASTRecordLayout(R->getDecl());
bool Ok = true;
- auto enumerateFields = [&]() -> void {
- for (unsigned I = 0, N = R->getNumFields(); I != N; ++I) {
- const Record::Field *Fi =
- R->getField(BigEndianTarget ? (N - 1 - I) : I);
- Pointer Elem = P.atField(Fi->Offset);
- size_t BitOffset =
- Offset + Layout.getFieldOffset(Fi->Decl->getFieldIndex());
- Ok = Ok && enumerateData(Elem, Ctx, BitOffset, F);
- }
- };
- auto enumerateBases = [&]() -> void {
- for (unsigned I = 0, N = R->getNumBases(); I != N; ++I) {
- const Record::Base *B = R->getBase(BigEndianTarget ? (N - 1 - I) : I);
- Pointer Elem = P.atField(B->Offset);
- CharUnits ByteOffset =
- Layout.getBaseClassOffset(cast<CXXRecordDecl>(B->Decl));
- size_t BitOffset = Offset + Ctx.getASTContext().toBits(ByteOffset);
- Ok = Ok && enumerateData(Elem, Ctx, BitOffset, F);
- }
- };
-
- if (BigEndianTarget) {
- enumerateFields();
- enumerateBases();
- } else {
- enumerateBases();
- enumerateFields();
+ for (const Record::Field &Fi : R->fields()) {
+ Pointer Elem = P.atField(Fi.Offset);
+ size_t BitOffset =
+ Offset + Layout.getFieldOffset(Fi.Decl->getFieldIndex());
+ Ok = Ok && enumerateData(Elem, Ctx, BitOffset, F);
+ }
+ for (const Record::Base &B : R->bases()) {
+ Pointer Elem = P.atField(B.Offset);
+ CharUnits ByteOffset =
+ Layout.getBaseClassOffset(cast<CXXRecordDecl>(B.Decl));
+ size_t BitOffset = Offset + Ctx.getASTContext().toBits(ByteOffset);
+ Ok = Ok && enumerateData(Elem, Ctx, BitOffset, F);
}
return Ok;
@@ -295,27 +218,28 @@ static bool CheckBitcastType(InterpState &S, CodePtr OpPC, QualType T,
static bool readPointerToBuffer(const Context &Ctx, const Pointer &FromPtr,
BitcastBuffer &Buffer, bool ReturnOnUninit) {
const ASTContext &ASTCtx = Ctx.getASTContext();
- bool SwapData = (ASTCtx.getTargetInfo().isLittleEndian() !=
- llvm::sys::IsLittleEndianHost);
- bool BigEndianTarget = ASTCtx.getTargetInfo().isBigEndian();
+ Endian TargetEndianness =
+ ASTCtx.getTargetInfo().isLittleEndian() ? Endian::Little : Endian::Big;
return enumeratePointerFields(
FromPtr, Ctx,
[&](const Pointer &P, PrimType T, size_t BitOffset,
bool PackedBools) -> bool {
- if (!P.isInitialized()) {
- assert(false && "Implement uninitialized value tracking");
- return ReturnOnUninit;
- }
+ // if (!P.isInitialized()) {
+ // assert(false && "Implement uninitialized value tracking");
+ // return ReturnOnUninit;
+ // }
- assert(P.isInitialized());
+ // assert(P.isInitialized());
// nullptr_t is a PT_Ptr for us, but it's still not std::is_pointer_v.
if (T == PT_Ptr)
assert(false && "Implement casting to pointer types");
CharUnits ObjectReprChars = ASTCtx.getTypeSizeInChars(P.getType());
unsigned BitWidth = ASTCtx.toBits(ObjectReprChars);
- llvm::SmallVector<std::byte> Buff(ObjectReprChars.getQuantity());
+ unsigned FullBitWidth = BitWidth;
+ auto Buff =
+ std::make_unique<std::byte[]>(ObjectReprChars.getQuantity());
// Work around floating point types that contain unused padding bytes.
// This is really just `long double` on x86, which is the only
// fundamental type with padding bytes.
@@ -323,34 +247,27 @@ static bool readPointerToBuffer(const Context &Ctx, const Pointer &FromPtr,
const Floating &F = P.deref<Floating>();
unsigned NumBits =
llvm::APFloatBase::getSizeInBits(F.getAPFloat().getSemantics());
- assert(NumBits % 8 == 0);
- assert(NumBits <= (ObjectReprChars.getQuantity() * 8));
- F.bitcastToMemory(Buff.data());
+ assert(fullByte(NumBits));
+ assert(NumBits <= FullBitWidth);
+ F.bitcastToMemory(Buff.get());
// Now, only (maybe) swap the actual size of the float, excluding the
// padding bits.
- if (SwapData)
- swapBytes(Buff.data(), NumBits / 8);
+ if (llvm::sys::IsBigEndianHost)
+ swapBytes(Buff.get(), NumBits / 8);
} else {
if (const FieldDecl *FD = P.getField(); FD && FD->isBitField())
- BitWidth = FD->getBitWidthValue(ASTCtx);
+ BitWidth = std::min(FD->getBitWidthValue(ASTCtx), FullBitWidth);
else if (T == PT_Bool && PackedBools)
BitWidth = 1;
- BITCAST_TYPE_SWITCH(T, {
- T Val = P.deref<T>();
- Val.bitcastToMemory(Buff.data());
- });
- if (SwapData)
- swapBytes(Buff.data(), ObjectReprChars.getQuantity());
- }
+ BITCAST_TYPE_SWITCH(T, { P.deref<T>().bitcastToMemory(Buff.get()); });
- if (BitWidth != (Buff.size() * 8) && BigEndianTarget) {
- Buffer.pushData(Buff.data() + (Buff.size() - 1 - (BitWidth / 8)),
- BitWidth, BigEndianTarget);
- } else {
- Buffer.pushData(Buff.data(), BitWidth, BigEndianTarget);
+ if (llvm::sys::IsBigEndianHost)
+ swapBytes(Buff.get(), FullBitWidth / 8);
}
+
+ Buffer.pushData(Buff.get(), BitOffset, BitWidth, TargetEndianness);
return true;
});
}
@@ -362,22 +279,28 @@ bool clang::interp::DoBitCast(InterpState &S, CodePtr OpPC, const Pointer &Ptr,
assert(Ptr.isBlockPointer());
assert(Buff);
- BitcastBuffer Buffer;
+ size_t BitSize = BuffSize * 8;
+ BitcastBuffer Buffer(BitSize);
if (!CheckBitcastType(S, OpPC, Ptr.getType(), /*IsToType=*/false))
return false;
bool Success = readPointerToBuffer(S.getContext(), Ptr, Buffer,
/*ReturnOnUninit=*/false);
- assert(Buffer.size() == BuffSize * 8);
-
HasIndeterminateBits = !Buffer.allInitialized();
- std::memcpy(Buff, Buffer.data(), BuffSize);
+
+ const ASTContext &ASTCtx = S.getASTContext();
+ Endian TargetEndianness =
+ ASTCtx.getTargetInfo().isLittleEndian() ? Endian::Little : Endian::Big;
+ auto B = Buffer.copyBits(0, BitSize, BitSize, TargetEndianness);
+
+ std::memcpy(Buff, B.get(), BuffSize);
if (llvm::sys::IsBigEndianHost)
swapBytes(Buff, BuffSize);
return Success;
}
+/// ---------------------------------------------------------------------------------------------------------------------
bool clang::interp::DoBitCastPtr(InterpState &S, CodePtr OpPC,
const Pointer &FromPtr, Pointer &ToPtr) {
@@ -394,43 +317,59 @@ bool clang::interp::DoBitCastPtr(InterpState &S, CodePtr OpPC,
if (!CheckBitcastType(S, OpPC, ToType, /*IsToType=*/true))
return false;
- BitcastBuffer Buffer;
+ const ASTContext &ASTCtx = S.getASTContext();
+
+ CharUnits ObjectReprChars = ASTCtx.getTypeSizeInChars(ToType);
+ BitcastBuffer Buffer(ASTCtx.toBits(ObjectReprChars));
readPointerToBuffer(S.getContext(), FromPtr, Buffer,
/*ReturnOnUninit=*/false);
// Now read the values out of the buffer again and into ToPtr.
- const ASTContext &ASTCtx = S.getASTContext();
- size_t BitOffset = 0;
+ Endian TargetEndianness =
+ ASTCtx.getTargetInfo().isLittleEndian() ? Endian::Little : Endian::Big;
bool Success = enumeratePointerFields(
ToPtr, S.getContext(),
- [&](const Pointer &P, PrimType T, size_t _, bool PackedBools) -> bool {
+ [&](const Pointer &P, PrimType T, size_t BitOffset,
+ bool PackedBools) -> bool {
+ CharUnits ObjectReprChars = ASTCtx.getTypeSizeInChars(P.getType());
+ unsigned FullBitWidth = ASTCtx.toBits(ObjectReprChars);
if (T == PT_Float) {
- CharUnits ObjectReprChars = ASTCtx.getTypeSizeInChars(P.getType());
const auto &Semantics = ASTCtx.getFloatTypeSemantics(P.getType());
unsigned NumBits = llvm::APFloatBase::getSizeInBits(Semantics);
- assert(NumBits % 8 == 0);
- assert(NumBits <= ASTCtx.toBits(ObjectReprChars));
- std::byte *M = Buffer.getBytes(BitOffset);
+ assert(fullByte(NumBits));
+ assert(NumBits <= FullBitWidth);
+ auto M = Buffer.copyBits(BitOffset, NumBits, FullBitWidth,
+ TargetEndianness);
if (llvm::sys::IsBigEndianHost)
- swapBytes(M, NumBits / 8);
+ swapBytes(M.get(), NumBits / 8);
- P.deref<Floating>() = Floating::bitcastFromMemory(M, Semantics);
+ P.deref<Floating>() = Floating::bitcastFromMemory(M.get(), Semantics);
P.initialize();
- BitOffset += ASTCtx.toBits(ObjectReprChars);
return true;
}
- BITCAST_TYPE_SWITCH_FIXED_SIZE(T, {
- std::byte *M = Buffer.getBytes(BitOffset);
+ unsigned BitWidth;
+ if (const FieldDecl *FD = P.getField(); FD && FD->isBitField())
+ BitWidth = std::min(FD->getBitWidthValue(ASTCtx), FullBitWidth);
+ else if (T == PT_Bool && PackedBools)
+ BitWidth = 1;
+ else
+ BitWidth = ASTCtx.toBits(ObjectReprChars);
- if (llvm::sys::IsBigEndianHost)
- swapBytes(M, T::bitWidth() / 8);
+ auto Memory = Buffer.copyBits(BitOffset, BitWidth, FullBitWidth,
+ TargetEndianness);
+ if (llvm::sys::IsBigEndianHost)
+ swapBytes(Memory.get(), FullBitWidth / 8);
- P.deref<T>() = T::bitcastFromMemory(M, T::bitWidth());
- P.initialize();
- BitOffset += T::bitWidth();
+ BITCAST_TYPE_SWITCH_FIXED_SIZE(T, {
+ if (BitWidth > 0)
+ P.deref<T>() = T::bitcastFromMemory(Memory.get(), T::bitWidth())
+ .truncate(BitWidth);
+ else
+ P.deref<T>() = T::zero();
});
+ P.initialize();
return true;
});
diff --git a/clang/lib/AST/CMakeLists.txt b/clang/lib/AST/CMakeLists.txt
index 52c6a45de9a26c..cb13c5225b713b 100644
--- a/clang/lib/AST/CMakeLists.txt
+++ b/clang/lib/AST/CMakeLists.txt
@@ -65,6 +65,7 @@ add_clang_library(clangAST
ExternalASTSource.cpp
FormatString.cpp
InheritViz.cpp
+ ByteCode/BitcastBuffer.cpp
ByteCode/ByteCodeEmitter.cpp
ByteCode/Compiler.cpp
ByteCode/Context.cpp
diff --git a/clang/test/AST/ByteCode/builtin-bit-cast-bitfields.cpp b/clang/test/AST/ByteCode/builtin-bit-cast-bitfields.cpp
new file mode 100644
index 00000000000000..1bb44f4f13443b
--- /dev/null
+++ b/clang/test/AST/ByteCode/builtin-bit-cast-bitfields.cpp
@@ -0,0 +1,437 @@
+// RUN: %clang_cc1 -verify=expected,both -std=c++2a -fsyntax-only -fexperimental-new-constant-interpreter %s
+// RUN: %clang_cc1 -verify=expected,both -std=c++2a -fsyntax-only -triple aarch64_be-linux-gnu -fexperimental-new-constant-interpreter %s
+// RUN: %clang_cc1 -verify=expected,both -std=c++2a -fsyntax-only -fexperimental-new-constant-interpreter -triple powerpc64le-unknown-unknown -mabi=ieeelongdouble %s
+// RUN: %clang_cc1 -verify=expected,both -std=c++2a -fsyntax-only -fexperimental-new-constant-interpreter -triple powerpc64-unknown-unknown -mabi=ieeelongdouble %s
+
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+# define LITTLE_END 1
+#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+# define LITTLE_END 0
+#else
+# error "huh?"
+#endif
+
+typedef decltype(nullptr) nullptr_t;
+typedef __INTPTR_TYPE__ intptr_t;
+typedef unsigned __INT16_TYPE__ uint16_t;
+typedef unsigned __INT32_TYPE__ uint32_t;
+typedef unsigned __INT64_TYPE__ uint64_t;
+
+static_assert(sizeof(int) == 4);
+static_assert(sizeof(long long) == 8);
+
+template <class To, class From>
+constexpr To bit_cast(const From &from) {
+ static_assert(sizeof(To) == sizeof(From));
+ return __builtin_bit_cast(To, from);
+}
+
+template <class Intermediate, class Init>
+constexpr bool check_round_trip(const Init &init) {
+ return bit_cast<Init>(bit_cast<Intermediate>(init)) == init;
+}
+
+template <class Intermediate, class Init>
+constexpr Init round_trip(const Init &init) {
+ return bit_cast<Init>(bit_cast<Intermediate>(init));
+}
+
+namespace std {
+enum byte : unsigned char {};
+} // namespace std
+
+template <int N, typename T = unsigned char, int Pad = 0>
+struct bits {
+ T : Pad;
+ T bits : N;
+
+ constexpr bool operator==(const T& rhs) const {
+ return bits == rhs;
+ }
+};
+
+template <int N, typename T, int P>
+constexpr bool operator==(const struct bits<N, T, P>& lhs, const struct bits<N, T, P>& rhs) {
+ return lhs.bits == rhs.bits;
+}
+
+template<int N>
+struct bytes {
+ using size_t = unsigned int;
+ unsigned char d[N];
+
+ constexpr unsigned char operator[](size_t index) {
+ if (index < N)
+ return d[index];
+ return -1;
+ }
+};
+
+namespace Sanity {
+ /// This is just one byte, and we extract 2 bits from it.
+ ///
+ /// 3 is 0000'0011.
+ /// For both LE and BE, the buffer will contain exactly that
+ /// byte, unaltered and not reordered in any way. It contains all 8 bits.
+ static_assert(__builtin_bit_cast(bits<2>, (unsigned char)3) == (LITTLE_END ? 3 : 0));
+
+ /// Similarly, we have one full byte of data, with the two most-significant
+ /// bits set:
+ /// 192 is 1100'0000
+ static_assert(__builtin_bit_cast(bits<2>, (unsigned char)192) == (LITTLE_END ? 0 : 3));
+
+
+ /// Here we are instead bitcasting two 1-bits into a destination of 8 bits.
+ /// On LE, we should pick the two least-significant bits. On BE, the opposite.
+ /// NOTE: Can't verify this with gcc.
+ constexpr auto B1 = bits<2>{3};
+ static_assert(__builtin_bit_cast(unsigned char, B1) == (LITTLE_END ? 3 : 192));
+
+ /// This should be 0000'0110.
+ /// On LE, this should result in 6.
+ /// On BE, 1100'0000 = 192.
+ constexpr auto B2 = bits<3>{6};
+ static_assert(__builtin_bit_cast(unsigned char, B2) == (LITTLE_END ? 6 : 192));
+
+ constexpr auto B3 = bits<4>{6};
+ static_assert(__builtin_bit_cast(unsigned char, B3) == (LITTLE_END ? 6 : 96));
+
+ struct B {
+ std::byte b0 : 4;
+ std::byte b1 : 4;
+ };
+
+ /// We can properly decompose one byte (8 bit) int two 4-bit bitfields.
+ constexpr struct { unsigned char b0; } T = {0xee};
+ constexpr B MB = __builtin_bit_cast(B, T);
+ static_assert(MB.b0 == 0xe);
+ static_assert(MB.b1 == 0xe);
+}
+
+namespace BitFields {
+ struct BitFields {
+ unsigned a : 2;
+ unsigned b : 30;
+ };
+
+ constexpr unsigned A = __builtin_bit_cast(unsigned, BitFields{3, 16});
+ static_assert(A == (LITTLE_END ? 67 : 3221225488));
+
+ struct S {
+ unsigned a : 2;
+ unsigned b : 28;
+ unsigned c : 2;
+ };
+
+ constexpr S s = __builtin_bit_cast(S, 0xFFFFFFFF);
+ static_assert(s.a == 3);
+ static_assert(s.b == 268435455);
+ static_assert(s.c == 3);
+
+ void bitfield_indeterminate() {
+ struct BF { unsigned char z : 2; };
+ enum byte : unsigned char {};
+
+ constexpr BF bf = {0x3};
+ /// Requires bitcasts to composite types.
+ static_assert(bit_cast<bits<2>>(bf).bits == bf.z);
+ static_assert(bit_cast<unsigned char>(bf));
+
+ static_assert(__builtin_bit_cast(byte, bf));
+
+ struct M {
+ // ref-note at +1 {{subobject declared here}}
+ unsigned char mem[sizeof(BF)];
+ };
+ // ref-error at +2 {{initialized by a constant expression}}
+ // ref-note at +1 {{not initialized}}
+ constexpr M m = bit_cast<M>(bf);
+
+ constexpr auto f = []() constexpr {
+ // bits<24, unsigned int, LITTLE_END ? 0 : 8> B = {0xc0ffee};
+ constexpr struct { unsigned short b1; unsigned char b0; } B = {0xc0ff, 0xee};
+ return bit_cast<bytes<4>>(B);
+ };
+
+ static_assert(f()[0] + f()[1] + f()[2] == 0xc0 + 0xff + 0xee);
+ {
+ // ref-error at +2 {{initialized by a constant expression}}
+ // ref-note at +1 {{read of uninitialized object is not allowed in a constant expression}}
+ constexpr auto _bad = f()[3];
+ }
+
+ struct B {
+ unsigned short s0 : 8;
+ unsigned short s1 : 8;
+ std::byte b0 : 4;
+ std::byte b1 : 4;
+ std::byte b2 : 4;
+ };
+ constexpr auto g = [f]() constexpr {
+ return bit_cast<B>(f());
+ };
+ static_assert(g().s0 + g().s1 + g().b0 + g().b1 == 0xc0 + 0xff + 0xe + 0xe);
+ {
+ // ref-error at +2 {{initialized by a constant expression}}
+ // ref-note at +1 {{read of uninitialized object is not allowed in a constant expression}}
+ constexpr auto _bad = g().b2;
+ }
+ }
+}
+
+namespace BoolVectors {
+ typedef bool bool32 __attribute__((ext_vector_type(32)));
+ constexpr auto v = bit_cast<bool32>(0xa1c0ffee);
+#if LITTLE_END
+ static_assert(!v[0]);
+ static_assert(v[1]);
+ static_assert(v[2]);
+ static_assert(v[3]);
+ static_assert(!v[4]);
+ static_assert(v[5]);
+ static_assert(v[6]);
+ static_assert(v[7]);
+
+ static_assert(v[8]);
+ static_assert(v[9]);
+ static_assert(v[10]);
+ static_assert(v[11]);
+ static_assert(v[12]);
+ static_assert(v[13]);
+ static_assert(v[14]);
+ static_assert(v[15]);
+
+ static_assert(!v[16]);
+ static_assert(!v[17]);
+ static_assert(!v[18]);
+ static_assert(!v[19]);
+ static_assert(!v[20]);
+ static_assert(!v[21]);
+ static_assert(v[22]);
+ static_assert(v[23]);
+
+ static_assert(v[24]);
+ static_assert(!v[25]);
+ static_assert(!v[26]);
+ static_assert(!v[27]);
+ static_assert(!v[28]);
+ static_assert(v[29]);
+ static_assert(!v[30]);
+ static_assert(v[31]);
+
+#else
+ static_assert(v[0]);
+ static_assert(!v[1]);
+ static_assert(v[2]);
+ static_assert(!v[3]);
+ static_assert(!v[4]);
+ static_assert(!v[5]);
+ static_assert(!v[6]);
+ static_assert(v[7]);
+
+ static_assert(v[8]);
+ static_assert(v[9]);
+ static_assert(!v[10]);
+ static_assert(!v[11]);
+ static_assert(!v[12]);
+ static_assert(!v[13]);
+ static_assert(!v[14]);
+ static_assert(!v[15]);
+
+ static_assert(v[16]);
+ static_assert(v[17]);
+ static_assert(v[18]);
+ static_assert(v[19]);
+ static_assert(v[20]);
+ static_assert(v[21]);
+ static_assert(v[22]);
+ static_assert(v[23]);
+
+ static_assert(v[24]);
+ static_assert(v[25]);
+ static_assert(v[26]);
+ static_assert(!v[27]);
+ static_assert(v[28]);
+ static_assert(v[29]);
+ static_assert(v[30]);
+ static_assert(!v[31]);
+#endif
+
+ struct pad {
+ unsigned short s;
+ unsigned char c;
+ };
+
+ constexpr auto p = bit_cast<pad>(v);
+ static_assert(p.s == (LITTLE_END ? 0xffee : 0xa1c0));
+ static_assert(p.c == (LITTLE_END ? 0xc0 : 0xff));
+}
+
+namespace TwoShorts {
+ struct B {
+ unsigned short s0 : 8;
+ unsigned short s1 : 8;
+ };
+ constexpr struct { unsigned short b1;} T = {0xc0ff};
+ constexpr B MB = __builtin_bit_cast(B, T);
+#if LITTLE_END
+ static_assert(MB.s0 == 0xff);
+ static_assert(MB.s1 == 0xc0);
+#else
+ static_assert(MB.s0 == 0xc0);
+ static_assert(MB.s1 == 0xff);
+
+#endif
+}
+
+typedef bool bool8 __attribute__((ext_vector_type(8)));
+typedef bool bool9 __attribute__((ext_vector_type(9)));
+typedef bool bool16 __attribute__((ext_vector_type(16)));
+typedef bool bool17 __attribute__((ext_vector_type(17)));
+typedef bool bool32 __attribute__((ext_vector_type(32)));
+typedef bool bool128 __attribute__((ext_vector_type(128)));
+
+static_assert(bit_cast<unsigned char>(bool8{1,0,1,0,1,0,1,0}) == (LITTLE_END ? 0x55 : 0xAA), "");
+constexpr bool8 b8 = __builtin_bit_cast(bool8, 0x55); // both-error {{'__builtin_bit_cast' source type 'int' does not match destination type 'bool8' (vector of 8 'bool' values) (4 vs 1 bytes)}}
+static_assert(check_round_trip<bool8>(static_cast<unsigned char>(0)), "");
+static_assert(check_round_trip<bool8>(static_cast<unsigned char>(1)), "");
+static_assert(check_round_trip<bool8>(static_cast<unsigned char>(0x55)), "");
+
+static_assert(bit_cast<unsigned short>(bool16{1,1,1,1,1,0,0,0, 1,1,1,1,0,1,0,0}) == (LITTLE_END ? 0x2F1F : 0xF8F4), "");
+
+static_assert(check_round_trip<bool16>(static_cast<short>(0xCAFE)), "");
+static_assert(check_round_trip<bool32>(static_cast<int>(0xCAFEBABE)), "");
+static_assert(check_round_trip<bool128>(static_cast<__int128_t>(0xCAFEBABE0C05FEFEULL)), "");
+
+static_assert(bit_cast<bits<8, uint16_t, 7>, uint16_t>(0xcafe) == (LITTLE_END ? 0x95 : 0x7f));
+static_assert(bit_cast<bits<4, uint16_t, 10>, uint16_t>(0xcafe) == (LITTLE_END ? 0x2 : 0xf));
+static_assert(bit_cast<bits<4, uint32_t, 19>, uint32_t>(0xa1cafe) == (LITTLE_END ? 0x4 : 0x5));
+
+struct S {
+ // little endian:
+ // MSB .... .... LSB
+ // |y| |x|
+ //
+ // big endian
+ // MSB .... .... LSB
+ // |x| |y|
+
+ unsigned char x : 4;
+ unsigned char y : 4;
+
+ constexpr bool operator==(S const &other) const {
+ return x == other.x && y == other.y;
+ }
+};
+
+constexpr S s{0xa, 0xb};
+static_assert(bit_cast<bits<8>>(s) == (LITTLE_END ? 0xba : 0xab));
+static_assert(bit_cast<bits<7>>(s) == (LITTLE_END
+ ? 0xba & 0x7f
+ : (0xab & 0xfe) >> 1));
+
+static_assert(round_trip<bits<8>>(s) == s);
+
+struct R {
+ unsigned int r : 31;
+ unsigned int : 0;
+ unsigned int : 32;
+ constexpr bool operator==(R const &other) const {
+ return r == other.r;
+ }
+ };
+using T = bits<31, signed long long>;
+constexpr R r{0x4ac0ffee};
+constexpr T t = bit_cast<T>(r);
+static_assert(t == ((0xFFFFFFFF8 << 28) | 0x4ac0ffee)); // sign extension
+
+static_assert(round_trip<T>(r) == r);
+static_assert(round_trip<R>(t) == t);
+
+
+/// The oversized bitfield is an error on Windows and not just a warning.
+#if !defined(_WIN32)
+struct U {
+ // expected-warning at +1 {{exceeds the width of its type}}
+ uint32_t trunc : 33;
+ uint32_t u : 31;
+ constexpr bool operator==(U const &other) const {
+ return trunc == other.trunc && u == other.u;
+ }
+};
+struct V {
+ uint64_t notrunc : 32;
+ uint64_t : 1;
+ uint64_t v : 31;
+ constexpr bool operator==(V const &other) const {
+ return notrunc == other.notrunc && v == other.v;
+ }
+};
+
+constexpr U u{static_cast<unsigned int>(~0), 0x4ac0ffee};
+constexpr V v = bit_cast<V>(u);
+static_assert(v.v == 0x4ac0ffee);
+
+static_assert(round_trip<V>(u) == u);
+static_assert(round_trip<U>(v) == v);
+
+constexpr auto w = bit_cast<bits<12, unsigned long, 33>>(u);
+static_assert(w == (LITTLE_END
+ ? 0x4ac0ffee & 0xFFF
+ : (0x4ac0ffee & (0xFFF << (31 - 12))) >> (31-12)
+ ));
+#endif
+
+
+namespace NestedStructures {
+ struct J {
+ struct {
+ uint16_t k : 12;
+ } K;
+ struct {
+ uint16_t l : 4;
+ } L;
+ };
+
+ static_assert(sizeof(J) == 4);
+ constexpr J j = bit_cast<J>(0x8c0ffee5);
+
+ static_assert(j.K.k == (LITTLE_END ? 0xee5 : 0x8c0));
+ static_assert(j.L.l == 0xf /* yay symmetry */);
+ static_assert(bit_cast<bits<4, uint16_t, 16>>(j) == 0xf);
+ struct N {
+ bits<12, uint16_t> k;
+ uint16_t : 16;
+ };
+ static_assert(bit_cast<N>(j).k == j.K.k);
+
+ struct M {
+ bits<4, uint16_t, 0> m[2];
+ constexpr bool operator==(const M& rhs) const {
+ return m[0] == rhs.m[0] && m[1] == rhs.m[1];
+ };
+ };
+ #if LITTLE_END == 1
+ constexpr uint16_t want[2] = {0x5, 0xf};
+ #else
+ constexpr uint16_t want[2] = {0x8000, 0xf000};
+ #endif
+
+ static_assert(bit_cast<M>(j) == bit_cast<M>(want));
+}
+
+namespace Enums {
+ // ensure we're packed into the top 2 bits
+ constexpr int pad = LITTLE_END ? 6 : 0;
+ struct X
+ {
+ char : pad;
+ enum class direction: char { left, right, up, down } direction : 2;
+ };
+
+ constexpr X x = { X::direction::down };
+ static_assert(bit_cast<bits<2, signed char, pad>>(x) == -1);
+ static_assert(bit_cast<bits<2, unsigned char, pad>>(x) == 3);
+ static_assert(
+ bit_cast<X>((unsigned char)0x40).direction == X::direction::right);
+}
diff --git a/clang/test/AST/ByteCode/builtin-bit-cast.cpp b/clang/test/AST/ByteCode/builtin-bit-cast.cpp
index 60e8c3a615c5e6..ce1b5f2dacedeb 100644
--- a/clang/test/AST/ByteCode/builtin-bit-cast.cpp
+++ b/clang/test/AST/ByteCode/builtin-bit-cast.cpp
@@ -164,72 +164,6 @@ namespace bitint {
// ref-note {{initializer of 'IB' is not a constant expression}}
}
-namespace BitFields {
- struct BitFields {
- unsigned a : 2;
- unsigned b : 30;
- };
-
- constexpr unsigned A = __builtin_bit_cast(unsigned, BitFields{3, 16}); // ref-error {{must be initialized by a constant expression}} \
- // ref-note {{not yet supported}} \
- // ref-note {{declared here}}
- static_assert(A == (LITTLE_END ? 67 : 3221225488)); // ref-error {{not an integral constant expression}} \
- // ref-note {{initializer of 'A'}}
-
-
- void bitfield_indeterminate() {
- struct BF { unsigned char z : 2; };
- enum byte : unsigned char {};
-
- constexpr BF bf = {0x3};
- /// Requires bitcasts to composite types.
- // static_assert(bit_cast<bits<2>>(bf).bits == bf.z);
- // static_assert(bit_cast<unsigned char>(bf));
-
-#if 0
- // static_assert(__builtin_bit_cast(byte, bf));
-
- struct M {
- // expected-note at +1 {{subobject declared here}}
- unsigned char mem[sizeof(BF)];
- };
- // expected-error at +2 {{initialized by a constant expression}}
- // expected-note at +1 {{not initialized}}
- constexpr M m = bit_cast<M>(bf);
-
- constexpr auto f = []() constexpr {
- // bits<24, unsigned int, LITTLE_END ? 0 : 8> B = {0xc0ffee};
- constexpr struct { unsigned short b1; unsigned char b0; } B = {0xc0ff, 0xee};
- return bit_cast<bytes<4>>(B);
- };
-
- static_assert(f()[0] + f()[1] + f()[2] == 0xc0 + 0xff + 0xee);
- {
- // expected-error at +2 {{initialized by a constant expression}}
- // expected-note at +1 {{read of uninitialized object is not allowed in a constant expression}}
- constexpr auto _bad = f()[3];
- }
-
- struct B {
- unsigned short s0 : 8;
- unsigned short s1 : 8;
- std::byte b0 : 4;
- std::byte b1 : 4;
- std::byte b2 : 4;
- };
- constexpr auto g = [f]() constexpr {
- return bit_cast<B>(f());
- };
- static_assert(g().s0 + g().s1 + g().b0 + g().b1 == 0xc0 + 0xff + 0xe + 0xe);
- {
- // expected-error at +2 {{initialized by a constant expression}}
- // expected-note at +1 {{read of uninitialized object is not allowed in a constant expression}}
- constexpr auto _bad = g().b2;
- }
-#endif
- }
-}
-
namespace Classes {
class A {
public:
@@ -488,27 +422,6 @@ static_assert(bit_cast<unsigned long long>(test_vector) == (LITTLE_END
static_assert(check_round_trip<uint2>(0xCAFEBABE0C05FEFEULL), "");
static_assert(check_round_trip<byte8>(0xCAFEBABE0C05FEFEULL), "");
-typedef bool bool8 __attribute__((ext_vector_type(8)));
-typedef bool bool9 __attribute__((ext_vector_type(9)));
-typedef bool bool16 __attribute__((ext_vector_type(16)));
-typedef bool bool17 __attribute__((ext_vector_type(17)));
-typedef bool bool32 __attribute__((ext_vector_type(32)));
-typedef bool bool128 __attribute__((ext_vector_type(128)));
-
-static_assert(bit_cast<unsigned char>(bool8{1,0,1,0,1,0,1,0}) == (LITTLE_END ? 0x55 : 0xAA), "");
-constexpr bool8 b8 = __builtin_bit_cast(bool8, 0x55); // both-error {{'__builtin_bit_cast' source type 'int' does not match destination type 'bool8' (vector of 8 'bool' values) (4 vs 1 bytes)}}
-#if 0
-static_assert(check_round_trip<bool8>(static_cast<unsigned char>(0)), "");
-static_assert(check_round_trip<bool8>(static_cast<unsigned char>(1)), "");
-static_assert(check_round_trip<bool8>(static_cast<unsigned char>(0x55)), "");
-
-static_assert(bit_cast<unsigned short>(bool16{1,1,1,1,1,0,0,0, 1,1,1,1,0,1,0,0}) == (LITTLE_END ? 0x2F1F : 0xF8F4), "");
-
-static_assert(check_round_trip<bool16>(static_cast<short>(0xCAFE)), "");
-static_assert(check_round_trip<bool32>(static_cast<int>(0xCAFEBABE)), "");
-static_assert(check_round_trip<bool128>(static_cast<__int128_t>(0xCAFEBABE0C05FEFEULL)), "");
-#endif
-
#if 0
// expected-error at +2 {{constexpr variable 'bad_bool9_to_short' must be initialized by a constant expression}}
// expected-note at +1 {{bit_cast involving type 'bool __attribute__((ext_vector_type(9)))' (vector of 9 'bool' values) is not allowed in a constant expression; element size 1 * element count 9 is not a multiple of the byte size 8}}
@@ -537,3 +450,20 @@ namespace test_complex {
constexpr double D = __builtin_bit_cast(double, test_float_complex);
constexpr int M = __builtin_bit_cast(int, test_int_complex); // both-error {{size of '__builtin_bit_cast' source type 'const _Complex unsigned int' does not match destination type 'int' (8 vs 4 bytes)}}
}
+
+
+namespace OversizedBitField {
+#if defined(_WIN32)
+ /// This is an error (not just a warning) on Windows and the field ends up with a size of 1 instead of 4.
+#else
+ typedef unsigned __INT16_TYPE__ uint16_t;
+ typedef unsigned __INT32_TYPE__ uint32_t;
+ struct S {
+ uint16_t a : 20; // both-warning {{exceeds the width of its type}}
+ };
+
+ static_assert(sizeof(S) == 4);
+ static_assert(__builtin_bit_cast(S, (uint32_t)32).a == (LITTLE_END ? 32 : 0)); // ref-error {{not an integral constant expression}} \
+ // ref-note {{constexpr bit_cast involving bit-field is not yet supported}}
+#endif
+}
diff --git a/clang/unittests/AST/ByteCode/BitcastBuffer.cpp b/clang/unittests/AST/ByteCode/BitcastBuffer.cpp
new file mode 100644
index 00000000000000..0f45d74fe5e208
--- /dev/null
+++ b/clang/unittests/AST/ByteCode/BitcastBuffer.cpp
@@ -0,0 +1,83 @@
+#include "../../../lib/AST/ByteCode/BitcastBuffer.h"
+#include "clang/AST/ASTContext.h"
+#include "gtest/gtest.h"
+#include <bitset>
+#include <cassert>
+#include <cmath>
+#include <memory>
+#include <string>
+
+using namespace clang;
+using namespace clang::interp;
+
+TEST(BitcastBuffer, PushData) {
+ BitcastBuffer Buff1(sizeof(int) * 8);
+
+ const unsigned V = 0xCAFEBABE;
+ std::byte Data[sizeof(V)];
+ std::memcpy(Data, &V, sizeof(V));
+
+ Endian HostEndianness =
+ llvm::sys::IsLittleEndianHost ? Endian::Little : Endian::Big;
+
+ Buff1.pushData(Data, 0, sizeof(V) * 8, HostEndianness);
+
+ // The buffer is in host-endianness.
+ if (llvm::sys::IsLittleEndianHost) {
+ ASSERT_EQ(Buff1.Data[0], std::byte{0xbe});
+ ASSERT_EQ(Buff1.Data[1], std::byte{0xba});
+ ASSERT_EQ(Buff1.Data[2], std::byte{0xfe});
+ ASSERT_EQ(Buff1.Data[3], std::byte{0xca});
+ } else {
+ ASSERT_EQ(Buff1.Data[0], std::byte{0xca});
+ ASSERT_EQ(Buff1.Data[1], std::byte{0xfe});
+ ASSERT_EQ(Buff1.Data[2], std::byte{0xba});
+ ASSERT_EQ(Buff1.Data[3], std::byte{0xbe});
+ }
+
+ {
+ unsigned V2;
+ auto D = Buff1.copyBits(0, sizeof(V) * 8, sizeof(V) * 8, Endian::Little);
+ std::memcpy(&V2, D.get(), sizeof(V));
+ ASSERT_EQ(V, V2);
+
+ D = Buff1.copyBits(0, sizeof(V) * 8, sizeof(V) * 8, Endian::Big);
+ std::memcpy(&V2, D.get(), sizeof(V));
+ ASSERT_EQ(V, V2);
+ }
+
+ BitcastBuffer Buff2(sizeof(int) * 8);
+ {
+ short s1 = 0xCAFE;
+ short s2 = 0xBABE;
+ std::byte sdata[2];
+
+ std::memcpy(sdata, &s1, sizeof(s1));
+ Buff2.pushData(sdata, 0, sizeof(s1) * 8, HostEndianness);
+ std::memcpy(sdata, &s2, sizeof(s2));
+ Buff2.pushData(sdata, sizeof(s1) * 8, sizeof(s2) * 8, HostEndianness);
+ }
+
+ if (llvm::sys::IsLittleEndianHost) {
+ ASSERT_EQ(Buff2.Data[0], std::byte{0xfe});
+ ASSERT_EQ(Buff2.Data[1], std::byte{0xca});
+ ASSERT_EQ(Buff2.Data[2], std::byte{0xbe});
+ ASSERT_EQ(Buff2.Data[3], std::byte{0xba});
+ } else {
+ ASSERT_EQ(Buff2.Data[0], std::byte{0xba});
+ ASSERT_EQ(Buff2.Data[1], std::byte{0xbe});
+ ASSERT_EQ(Buff2.Data[2], std::byte{0xca});
+ ASSERT_EQ(Buff2.Data[3], std::byte{0xfe});
+ }
+
+ {
+ unsigned V;
+ auto D = Buff2.copyBits(0, sizeof(V) * 8, sizeof(V) * 8, Endian::Little);
+ std::memcpy(&V, D.get(), sizeof(V));
+ ASSERT_EQ(V, 0xBABECAFE);
+
+ D = Buff2.copyBits(0, sizeof(V) * 8, sizeof(V) * 8, Endian::Big);
+ std::memcpy(&V, D.get(), sizeof(V));
+ ASSERT_EQ(V, 0xBABECAFE);
+ }
+}
diff --git a/clang/unittests/AST/ByteCode/CMakeLists.txt b/clang/unittests/AST/ByteCode/CMakeLists.txt
index ea727cdd4412be..b862fb4834fbdc 100644
--- a/clang/unittests/AST/ByteCode/CMakeLists.txt
+++ b/clang/unittests/AST/ByteCode/CMakeLists.txt
@@ -1,4 +1,5 @@
add_clang_unittest(InterpTests
+ BitcastBuffer.cpp
Descriptor.cpp
toAPValue.cpp
)
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