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Review".
This revision was automatically updated to reflect the committed changes.
Closed by commit rL363620: Rewrite ConstStructBuilder with a mechanism that can
cope with splitting and… (authored by rsmith, committed by ).
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Changed prior to commit:
https://reviews.llvm.org/D63371?vs=205182&id=205184#toc
Repository:
rL LLVM
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D63371/new/
https://reviews.llvm.org/D63371
Files:
cfe/trunk/lib/CodeGen/CGExprConstant.cpp
cfe/trunk/test/CodeGenCXX/designated-init.cpp
Index: cfe/trunk/test/CodeGenCXX/designated-init.cpp
===================================================================
--- cfe/trunk/test/CodeGenCXX/designated-init.cpp
+++ cfe/trunk/test/CodeGenCXX/designated-init.cpp
@@ -0,0 +1,66 @@
+// RUN: %clang_cc1 -std=c++98 -emit-llvm -o - %s -triple x86_64-linux-gnu | FileCheck %s
+// RUN: %clang_cc1 -std=c++11 -emit-llvm -o - %s -triple x86_64-linux-gnu | FileCheck %s
+
+struct A { int x, y[3]; };
+struct B { A a; };
+
+// CHECK: @b = global %{{[^ ]*}} { %{{[^ ]*}} { i32 1, [3 x i32] [i32 2, i32 5, i32 4] } }
+B b = {(A){1, 2, 3, 4}, .a.y[1] = 5};
+
+union U {
+ int n;
+ float f;
+};
+struct C {
+ int x;
+ U u[3];
+};
+struct D {
+ C c;
+};
+
+// CHECK: @d1 = {{.*}} { i32 1, [3 x %[[U:.*]]] [%[[U]] { i32 2 }, %[[U]] { i32 5 }, %[[U]] { i32 4 }] }
+D d1 = {(C){1, {{.n=2}, {.f=3}, {.n=4}}}, .c.u[1].n = 5};
+
+// CHECK: @d2 = {{.*}} { i32 1, { %[[U]], float, %[[U]] } { %[[U]] { i32 2 }, float 5.{{0*}}e+00, %[[U]] { i32 4 } } }
+D d2 = {(C){1, 2, 3, 4}, .c.u[1].f = 5};
+
+struct Bitfield {
+ int a : 3;
+ int b : 4;
+ int c : 5;
+};
+struct WithBitfield {
+ int n;
+ Bitfield b;
+};
+// CHECK: @bitfield = {{.*}} { i32 1, { i8, i8, [2 x i8] } { i8 42, i8 2, [2 x i8] undef } }
+WithBitfield bitfield = {1, (Bitfield){2, 3, 4}, .b.b = 5};
+
+struct String {
+ const char buffer[12];
+};
+struct WithString {
+ String str;
+};
+// CHECK: @string = {{.*}} [12 x i8] c"Hello World\00" } }
+WithString string = {(String){"hello world"}, .str.buffer[0] = 'H', .str.buffer[6] = 'W'};
+
+struct LargeArray {
+ int arr[4096];
+};
+struct WithLargeArray {
+ LargeArray arr;
+};
+// CHECK: @large = global { { <{ [11 x i32], [4085 x i32] }> } } { { <{ [11 x i32], [4085 x i32] }> } { <{ [11 x i32], [4085 x i32] }> <{ [11 x i32] [i32 1, i32 2, i32 3, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 10], [4085 x i32] zeroinitializer }> } }
+WithLargeArray large = {(LargeArray){1, 2, 3}, .arr.arr[10] = 10};
+
+union OverwritePaddingWithBitfield {
+ struct Padding { unsigned : 8; char c; } padding;
+ char bitfield : 3;
+};
+struct WithOverwritePaddingWithBitfield {
+ OverwritePaddingWithBitfield a;
+};
+// CHECK: @overwrite_padding = global { { i8, i8 } } { { i8, i8 } { i8 3, i8 1 } }
+WithOverwritePaddingWithBitfield overwrite_padding = {(OverwritePaddingWithBitfield){1}, .a.bitfield = 3};
Index: cfe/trunk/lib/CodeGen/CGExprConstant.cpp
===================================================================
--- cfe/trunk/lib/CodeGen/CGExprConstant.cpp
+++ cfe/trunk/lib/CodeGen/CGExprConstant.cpp
@@ -22,6 +22,8 @@
#include "clang/AST/RecordLayout.h"
#include "clang/AST/StmtVisitor.h"
#include "clang/Basic/Builtins.h"
+#include "llvm/ADT/Sequence.h"
+#include "llvm/ADT/STLExtras.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Function.h"
@@ -30,345 +32,636 @@
using namespace CodeGen;
//===----------------------------------------------------------------------===//
-// ConstStructBuilder
+// ConstantAggregateBuilder
//===----------------------------------------------------------------------===//
namespace {
class ConstExprEmitter;
-class ConstStructBuilder {
- CodeGenModule &CGM;
- ConstantEmitter &Emitter;
-
- bool Packed;
- CharUnits NextFieldOffsetInChars;
- CharUnits LLVMStructAlignment;
- SmallVector<llvm::Constant *, 32> Elements;
-public:
- static llvm::Constant *BuildStruct(ConstantEmitter &Emitter,
- ConstExprEmitter *ExprEmitter,
- llvm::Constant *Base,
- InitListExpr *Updater,
- QualType ValTy);
- static llvm::Constant *BuildStruct(ConstantEmitter &Emitter,
- InitListExpr *ILE, QualType StructTy);
- static llvm::Constant *BuildStruct(ConstantEmitter &Emitter,
- const APValue &Value, QualType ValTy);
-
-private:
- ConstStructBuilder(ConstantEmitter &emitter)
- : CGM(emitter.CGM), Emitter(emitter), Packed(false),
- NextFieldOffsetInChars(CharUnits::Zero()),
- LLVMStructAlignment(CharUnits::One()) { }
-
- void AppendField(const FieldDecl *Field, uint64_t FieldOffset,
- llvm::Constant *InitExpr);
-
- void AppendBytes(CharUnits FieldOffsetInChars, llvm::Constant *InitCst);
-
- void AppendBitField(const FieldDecl *Field, uint64_t FieldOffset,
- llvm::ConstantInt *InitExpr);
- void AppendPadding(CharUnits PadSize);
-
- void AppendTailPadding(CharUnits RecordSize);
-
- void ConvertStructToPacked();
+struct ConstantAggregateBuilderUtils {
+ CodeGenModule &CGM;
- bool Build(InitListExpr *ILE);
- bool Build(ConstExprEmitter *Emitter, llvm::Constant *Base,
- InitListExpr *Updater);
- bool Build(const APValue &Val, const RecordDecl *RD, bool IsPrimaryBase,
- const CXXRecordDecl *VTableClass, CharUnits BaseOffset);
- llvm::Constant *Finalize(QualType Ty);
+ ConstantAggregateBuilderUtils(CodeGenModule &CGM) : CGM(CGM) {}
CharUnits getAlignment(const llvm::Constant *C) const {
- if (Packed) return CharUnits::One();
return CharUnits::fromQuantity(
CGM.getDataLayout().getABITypeAlignment(C->getType()));
}
- CharUnits getSizeInChars(const llvm::Constant *C) const {
- return CharUnits::fromQuantity(
- CGM.getDataLayout().getTypeAllocSize(C->getType()));
+ CharUnits getSize(llvm::Type *Ty) const {
+ return CharUnits::fromQuantity(CGM.getDataLayout().getTypeAllocSize(Ty));
}
-};
-
-void ConstStructBuilder::
-AppendField(const FieldDecl *Field, uint64_t FieldOffset,
- llvm::Constant *InitCst) {
- const ASTContext &Context = CGM.getContext();
-
- CharUnits FieldOffsetInChars = Context.toCharUnitsFromBits(FieldOffset);
-
- AppendBytes(FieldOffsetInChars, InitCst);
-}
-
-void ConstStructBuilder::
-AppendBytes(CharUnits FieldOffsetInChars, llvm::Constant *InitCst) {
- assert(NextFieldOffsetInChars <= FieldOffsetInChars
- && "Field offset mismatch!");
-
- CharUnits FieldAlignment = getAlignment(InitCst);
-
- // Round up the field offset to the alignment of the field type.
- CharUnits AlignedNextFieldOffsetInChars =
- NextFieldOffsetInChars.alignTo(FieldAlignment);
-
- if (AlignedNextFieldOffsetInChars < FieldOffsetInChars) {
- // We need to append padding.
- AppendPadding(FieldOffsetInChars - NextFieldOffsetInChars);
-
- assert(NextFieldOffsetInChars == FieldOffsetInChars &&
- "Did not add enough padding!");
+ CharUnits getSize(const llvm::Constant *C) const {
+ return getSize(C->getType());
+ }
- AlignedNextFieldOffsetInChars =
- NextFieldOffsetInChars.alignTo(FieldAlignment);
+ llvm::Constant *getPadding(CharUnits PadSize) const {
+ llvm::Type *Ty = CGM.Int8Ty;
+ if (PadSize > CharUnits::One())
+ Ty = llvm::ArrayType::get(Ty, PadSize.getQuantity());
+ return llvm::UndefValue::get(Ty);
}
- if (AlignedNextFieldOffsetInChars > FieldOffsetInChars) {
- assert(!Packed && "Alignment is wrong even with a packed struct!");
+ llvm::Constant *getZeroes(CharUnits ZeroSize) const {
+ llvm::Type *Ty = llvm::ArrayType::get(CGM.Int8Ty, ZeroSize.getQuantity());
+ return llvm::ConstantAggregateZero::get(Ty);
+ }
+};
- // Convert the struct to a packed struct.
- ConvertStructToPacked();
+/// Incremental builder for an llvm::Constant* holding a struct or array
+/// constant.
+class ConstantAggregateBuilder : private ConstantAggregateBuilderUtils {
+ /// The elements of the constant. These two arrays must have the same size;
+ /// Offsets[i] describes the offset of Elems[i] within the constant. The
+ /// elements are kept in increasing offset order, and we ensure that there
+ /// is no overlap: Offsets[i+1] >= Offsets[i] + getSize(Elemes[i]).
+ ///
+ /// This may contain explicit padding elements (in order to create a
+ /// natural layout), but need not. Gaps between elements are implicitly
+ /// considered to be filled with undef.
+ llvm::SmallVector<llvm::Constant*, 32> Elems;
+ llvm::SmallVector<CharUnits, 32> Offsets;
+
+ /// The size of the constant (the maximum end offset of any added element).
+ /// May be larger than the end of Elems.back() if we split the last element
+ /// and removed some trailing undefs.
+ CharUnits Size = CharUnits::Zero();
+
+ /// This is true only if laying out Elems in order as the elements of a
+ /// non-packed LLVM struct will give the correct layout.
+ bool NaturalLayout = true;
+
+ bool split(size_t Index, CharUnits Hint);
+ Optional<size_t> splitAt(CharUnits Pos);
+
+ static llvm::Constant *buildFrom(CodeGenModule &CGM,
+ ArrayRef<llvm::Constant *> Elems,
+ ArrayRef<CharUnits> Offsets,
+ CharUnits StartOffset, CharUnits Size,
+ bool NaturalLayout, llvm::Type *DesiredTy,
+ bool AllowOversized);
- // After we pack the struct, we may need to insert padding.
- if (NextFieldOffsetInChars < FieldOffsetInChars) {
- // We need to append padding.
- AppendPadding(FieldOffsetInChars - NextFieldOffsetInChars);
+public:
+ ConstantAggregateBuilder(CodeGenModule &CGM)
+ : ConstantAggregateBuilderUtils(CGM) {}
- assert(NextFieldOffsetInChars == FieldOffsetInChars &&
- "Did not add enough padding!");
- }
- AlignedNextFieldOffsetInChars = NextFieldOffsetInChars;
+ /// Update or overwrite the value starting at \p Offset with \c C.
+ ///
+ /// \param AllowOverwrite If \c true, this constant might overwrite (part of)
+ /// a constant that has already been added. This flag is only used to
+ /// detect bugs.
+ bool add(llvm::Constant *C, CharUnits Offset, bool AllowOverwrite);
+
+ /// Update or overwrite the bits starting at \p OffsetInBits with \p Bits.
+ bool addBits(llvm::APInt Bits, uint64_t OffsetInBits, bool AllowOverwrite);
+
+ /// Attempt to condense the value starting at \p Offset to a constant of type
+ /// \p DesiredTy.
+ void condense(CharUnits Offset, llvm::Type *DesiredTy);
+
+ /// Produce a constant representing the entire accumulated value, ideally of
+ /// the specified type. If \p AllowOversized, the constant might be larger
+ /// than implied by \p DesiredTy (eg, if there is a flexible array member).
+ /// Otherwise, the constant will be of exactly the same size as \p DesiredTy
+ /// even if we can't represent it as that type.
+ llvm::Constant *build(llvm::Type *DesiredTy, bool AllowOversized) const {
+ return buildFrom(CGM, Elems, Offsets, CharUnits::Zero(), Size,
+ NaturalLayout, DesiredTy, AllowOversized);
}
+};
- // Add the field.
- Elements.push_back(InitCst);
- NextFieldOffsetInChars = AlignedNextFieldOffsetInChars +
- getSizeInChars(InitCst);
-
- if (Packed)
- assert(LLVMStructAlignment == CharUnits::One() &&
- "Packed struct not byte-aligned!");
- else
- LLVMStructAlignment = std::max(LLVMStructAlignment, FieldAlignment);
+template<typename Container, typename Range = std::initializer_list<
+ typename Container::value_type>>
+static void replace(Container &C, size_t BeginOff, size_t EndOff, Range Vals) {
+ assert(BeginOff <= EndOff && "invalid replacement range");
+ llvm::replace(C, C.begin() + BeginOff, C.begin() + EndOff, Vals);
+}
+
+bool ConstantAggregateBuilder::add(llvm::Constant *C, CharUnits Offset,
+ bool AllowOverwrite) {
+ // Common case: appending to a layout.
+ if (Offset >= Size) {
+ CharUnits Align = getAlignment(C);
+ CharUnits AlignedSize = Size.alignTo(Align);
+ if (AlignedSize > Offset || Offset.alignTo(Align) != Offset)
+ NaturalLayout = false;
+ else if (AlignedSize < Offset) {
+ Elems.push_back(getPadding(Offset - Size));
+ Offsets.push_back(Size);
+ }
+ Elems.push_back(C);
+ Offsets.push_back(Offset);
+ Size = Offset + getSize(C);
+ return true;
+ }
+
+ // Uncommon case: constant overlaps what we've already created.
+ llvm::Optional<size_t> FirstElemToReplace = splitAt(Offset);
+ if (!FirstElemToReplace)
+ return false;
+
+ CharUnits CSize = getSize(C);
+ llvm::Optional<size_t> LastElemToReplace = splitAt(Offset + CSize);
+ if (!LastElemToReplace)
+ return false;
+
+ assert((FirstElemToReplace == LastElemToReplace || AllowOverwrite) &&
+ "unexpectedly overwriting field");
+
+ replace(Elems, *FirstElemToReplace, *LastElemToReplace, {C});
+ replace(Offsets, *FirstElemToReplace, *LastElemToReplace, {Offset});
+ Size = std::max(Size, Offset + CSize);
+ NaturalLayout = false;
+ return true;
}
-void ConstStructBuilder::AppendBitField(const FieldDecl *Field,
- uint64_t FieldOffset,
- llvm::ConstantInt *CI) {
+bool ConstantAggregateBuilder::addBits(llvm::APInt Bits, uint64_t OffsetInBits,
+ bool AllowOverwrite) {
const ASTContext &Context = CGM.getContext();
- const uint64_t CharWidth = Context.getCharWidth();
- uint64_t NextFieldOffsetInBits = Context.toBits(NextFieldOffsetInChars);
- if (FieldOffset > NextFieldOffsetInBits) {
- // We need to add padding.
- CharUnits PadSize = Context.toCharUnitsFromBits(
- llvm::alignTo(FieldOffset - NextFieldOffsetInBits,
- Context.getTargetInfo().getCharAlign()));
+ const uint64_t CharWidth = CGM.getContext().getCharWidth();
- AppendPadding(PadSize);
- }
+ // Offset of where we want the first bit to go within the bits of the
+ // current char.
+ unsigned OffsetWithinChar = OffsetInBits % CharWidth;
+
+ // We split bit-fields up into individual bytes. Walk over the bytes and
+ // update them.
+ for (CharUnits OffsetInChars = Context.toCharUnitsFromBits(OffsetInBits);
+ /**/; ++OffsetInChars) {
+ // Number of bits we want to fill in this char.
+ unsigned WantedBits =
+ std::min((uint64_t)Bits.getBitWidth(), CharWidth - OffsetWithinChar);
+
+ // Get a char containing the bits we want in the right places. The other
+ // bits have unspecified values.
+ llvm::APInt BitsThisChar = Bits;
+ if (BitsThisChar.getBitWidth() < CharWidth)
+ BitsThisChar = BitsThisChar.zext(CharWidth);
+ if (CGM.getDataLayout().isBigEndian()) {
+ // Figure out how much to shift by. We may need to left-shift if we have
+ // less than one byte of Bits left.
+ int Shift = Bits.getBitWidth() - CharWidth + OffsetWithinChar;
+ if (Shift > 0)
+ BitsThisChar.lshrInPlace(Shift);
+ else if (Shift < 0)
+ BitsThisChar = BitsThisChar.shl(-Shift);
+ } else {
+ BitsThisChar = BitsThisChar.shl(OffsetWithinChar);
+ }
+ if (BitsThisChar.getBitWidth() > CharWidth)
+ BitsThisChar = BitsThisChar.trunc(CharWidth);
- uint64_t FieldSize = Field->getBitWidthValue(Context);
+ if (WantedBits == CharWidth) {
+ // Got a full byte: just add it directly.
+ add(llvm::ConstantInt::get(CGM.getLLVMContext(), BitsThisChar),
+ OffsetInChars, AllowOverwrite);
+ } else {
+ // Partial byte: update the existing integer if there is one. If we
+ // can't split out a 1-CharUnit range to update, then we can't add
+ // these bits and fail the entire constant emission.
+ llvm::Optional<size_t> FirstElemToUpdate = splitAt(OffsetInChars);
+ if (!FirstElemToUpdate)
+ return false;
+ llvm::Optional<size_t> LastElemToUpdate =
+ splitAt(OffsetInChars + CharUnits::One());
+ if (!LastElemToUpdate)
+ return false;
+ assert(*LastElemToUpdate - *FirstElemToUpdate < 2 &&
+ "should have at most one element covering one byte");
- llvm::APInt FieldValue = CI->getValue();
+ // Figure out which bits we want and discard the rest.
+ llvm::APInt UpdateMask(CharWidth, 0);
+ if (CGM.getDataLayout().isBigEndian())
+ UpdateMask.setBits(CharWidth - OffsetWithinChar - WantedBits,
+ CharWidth - OffsetWithinChar);
+ else
+ UpdateMask.setBits(OffsetWithinChar, OffsetWithinChar + WantedBits);
+ BitsThisChar &= UpdateMask;
- // Promote the size of FieldValue if necessary
- // FIXME: This should never occur, but currently it can because initializer
- // constants are cast to bool, and because clang is not enforcing bitfield
- // width limits.
- if (FieldSize > FieldValue.getBitWidth())
- FieldValue = FieldValue.zext(FieldSize);
+ if (*FirstElemToUpdate == *LastElemToUpdate ||
+ Elems[*FirstElemToUpdate]->isNullValue() ||
+ isa<llvm::UndefValue>(Elems[*FirstElemToUpdate])) {
+ // All existing bits are either zero or undef.
+ add(llvm::ConstantInt::get(CGM.getLLVMContext(), BitsThisChar),
+ OffsetInChars, /*AllowOverwrite*/ true);
+ } else {
+ llvm::Constant *&ToUpdate = Elems[*FirstElemToUpdate];
+ // In order to perform a partial update, we need the existing bitwise
+ // value, which we can only extract for a constant int.
+ auto *CI = dyn_cast<llvm::ConstantInt>(ToUpdate);
+ if (!CI)
+ return false;
+ // Because this is a 1-CharUnit range, the constant occupying it must
+ // be exactly one CharUnit wide.
+ assert(CI->getBitWidth() == CharWidth && "splitAt failed");
+ assert((!(CI->getValue() & UpdateMask) || AllowOverwrite) &&
+ "unexpectedly overwriting bitfield");
+ BitsThisChar |= (CI->getValue() & ~UpdateMask);
+ ToUpdate = llvm::ConstantInt::get(CGM.getLLVMContext(), BitsThisChar);
+ }
+ }
- // Truncate the size of FieldValue to the bit field size.
- if (FieldSize < FieldValue.getBitWidth())
- FieldValue = FieldValue.trunc(FieldSize);
+ // Stop if we've added all the bits.
+ if (WantedBits == Bits.getBitWidth())
+ break;
+
+ // Remove the consumed bits from Bits.
+ if (!CGM.getDataLayout().isBigEndian())
+ Bits.lshrInPlace(WantedBits);
+ Bits = Bits.trunc(Bits.getBitWidth() - WantedBits);
- NextFieldOffsetInBits = Context.toBits(NextFieldOffsetInChars);
- if (FieldOffset < NextFieldOffsetInBits) {
- // Either part of the field or the entire field can go into the previous
- // byte.
- assert(!Elements.empty() && "Elements can't be empty!");
+ // The remanining bits go at the start of the following bytes.
+ OffsetWithinChar = 0;
+ }
- unsigned BitsInPreviousByte = NextFieldOffsetInBits - FieldOffset;
+ return true;
+}
- bool FitsCompletelyInPreviousByte =
- BitsInPreviousByte >= FieldValue.getBitWidth();
+/// Returns a position within Elems and Offsets such that all elements
+/// before the returned index end before Pos and all elements at or after
+/// the returned index begin at or after Pos. Splits elements as necessary
+/// to ensure this. Returns None if we find something we can't split.
+Optional<size_t> ConstantAggregateBuilder::splitAt(CharUnits Pos) {
+ if (Pos >= Size)
+ return Offsets.size();
+
+ while (true) {
+ auto FirstAfterPos = std::upper_bound(Offsets.begin(), Offsets.end(), Pos);
+ if (FirstAfterPos == Offsets.begin())
+ return 0;
+
+ // If we already have an element starting at Pos, we're done.
+ size_t LastAtOrBeforePosIndex = FirstAfterPos - Offsets.begin() - 1;
+ if (Offsets[LastAtOrBeforePosIndex] == Pos)
+ return LastAtOrBeforePosIndex;
+
+ // We found an element starting before Pos. Check for overlap.
+ if (Offsets[LastAtOrBeforePosIndex] +
+ getSize(Elems[LastAtOrBeforePosIndex]) <= Pos)
+ return LastAtOrBeforePosIndex + 1;
+
+ // Try to decompose it into smaller constants.
+ if (!split(LastAtOrBeforePosIndex, Pos))
+ return None;
+ }
+}
- llvm::APInt Tmp = FieldValue;
+/// Split the constant at index Index, if possible. Return true if we did.
+/// Hint indicates the location at which we'd like to split, but may be
+/// ignored.
+bool ConstantAggregateBuilder::split(size_t Index, CharUnits Hint) {
+ NaturalLayout = false;
+ llvm::Constant *C = Elems[Index];
+ CharUnits Offset = Offsets[Index];
+
+ if (auto *CA = dyn_cast<llvm::ConstantAggregate>(C)) {
+ replace(Elems, Index, Index + 1,
+ llvm::map_range(llvm::seq(0u, CA->getNumOperands()),
+ [&](unsigned Op) { return CA->getOperand(Op); }));
+ if (auto *Seq = dyn_cast<llvm::SequentialType>(CA->getType())) {
+ // Array or vector.
+ CharUnits ElemSize = getSize(Seq->getElementType());
+ replace(
+ Offsets, Index, Index + 1,
+ llvm::map_range(llvm::seq(0u, CA->getNumOperands()),
+ [&](unsigned Op) { return Offset + Op * ElemSize; }));
+ } else {
+ // Must be a struct.
+ auto *ST = cast<llvm::StructType>(CA->getType());
+ const llvm::StructLayout *Layout =
+ CGM.getDataLayout().getStructLayout(ST);
+ replace(Offsets, Index, Index + 1,
+ llvm::map_range(
+ llvm::seq(0u, CA->getNumOperands()), [&](unsigned Op) {
+ return Offset + CharUnits::fromQuantity(
+ Layout->getElementOffset(Op));
+ }));
+ }
+ return true;
+ }
+
+ if (auto *CDS = dyn_cast<llvm::ConstantDataSequential>(C)) {
+ // FIXME: If possible, split into two ConstantDataSequentials at Hint.
+ CharUnits ElemSize = getSize(CDS->getElementType());
+ replace(Elems, Index, Index + 1,
+ llvm::map_range(llvm::seq(0u, CDS->getNumElements()),
+ [&](unsigned Elem) {
+ return CDS->getElementAsConstant(Elem);
+ }));
+ replace(Offsets, Index, Index + 1,
+ llvm::map_range(
+ llvm::seq(0u, CDS->getNumElements()),
+ [&](unsigned Elem) { return Offset + Elem * ElemSize; }));
+ return true;
+ }
+
+ if (auto *CAZ = dyn_cast<llvm::ConstantAggregateZero>(C)) {
+ CharUnits ElemSize = getSize(C);
+ assert(Hint > Offset && Hint < Offset + ElemSize && "nothing to split");
+ replace(Elems, Index, Index + 1,
+ {getZeroes(Hint - Offset), getZeroes(Offset + ElemSize - Hint)});
+ replace(Offsets, Index, Index + 1, {Offset, Hint});
+ return true;
+ }
+
+ if (isa<llvm::UndefValue>(C)) {
+ replace(Elems, Index, Index + 1, {});
+ replace(Offsets, Index, Index + 1, {});
+ return true;
+ }
+
+ // FIXME: We could split a ConstantInt if the need ever arose.
+ // We don't need to do this to handle bit-fields because we always eagerly
+ // split them into 1-byte chunks.
- if (!FitsCompletelyInPreviousByte) {
- unsigned NewFieldWidth = FieldSize - BitsInPreviousByte;
+ return false;
+}
- if (CGM.getDataLayout().isBigEndian()) {
- Tmp.lshrInPlace(NewFieldWidth);
- Tmp = Tmp.trunc(BitsInPreviousByte);
+static llvm::Constant *
+EmitArrayConstant(CodeGenModule &CGM, llvm::ArrayType *DesiredType,
+ llvm::Type *CommonElementType, unsigned ArrayBound,
+ SmallVectorImpl<llvm::Constant *> &Elements,
+ llvm::Constant *Filler);
- // We want the remaining high bits.
- FieldValue = FieldValue.trunc(NewFieldWidth);
- } else {
- Tmp = Tmp.trunc(BitsInPreviousByte);
+llvm::Constant *ConstantAggregateBuilder::buildFrom(
+ CodeGenModule &CGM, ArrayRef<llvm::Constant *> Elems,
+ ArrayRef<CharUnits> Offsets, CharUnits StartOffset, CharUnits Size,
+ bool NaturalLayout, llvm::Type *DesiredTy, bool AllowOversized) {
+ ConstantAggregateBuilderUtils Utils(CGM);
+
+ if (Elems.empty())
+ return llvm::UndefValue::get(DesiredTy);
+
+ auto Offset = [&](size_t I) { return Offsets[I] - StartOffset; };
+
+ // If we want an array type, see if all the elements are the same type and
+ // appropriately spaced.
+ if (llvm::ArrayType *ATy = dyn_cast<llvm::ArrayType>(DesiredTy)) {
+ assert(!AllowOversized && "oversized array emission not supported");
+
+ bool CanEmitArray = true;
+ llvm::Type *CommonType = Elems[0]->getType();
+ llvm::Constant *Filler = llvm::Constant::getNullValue(CommonType);
+ CharUnits ElemSize = Utils.getSize(ATy->getElementType());
+ SmallVector<llvm::Constant*, 32> ArrayElements;
+ for (size_t I = 0; I != Elems.size(); ++I) {
+ // Skip zeroes; we'll use a zero value as our array filler.
+ if (Elems[I]->isNullValue())
+ continue;
- // We want the remaining low bits.
- FieldValue.lshrInPlace(BitsInPreviousByte);
- FieldValue = FieldValue.trunc(NewFieldWidth);
+ // All remaining elements must be the same type.
+ if (Elems[I]->getType() != CommonType ||
+ Offset(I) % ElemSize != 0) {
+ CanEmitArray = false;
+ break;
}
+ ArrayElements.resize(Offset(I) / ElemSize + 1, Filler);
+ ArrayElements.back() = Elems[I];
}
- Tmp = Tmp.zext(CharWidth);
- if (CGM.getDataLayout().isBigEndian()) {
- if (FitsCompletelyInPreviousByte)
- Tmp = Tmp.shl(BitsInPreviousByte - FieldValue.getBitWidth());
- } else {
- Tmp = Tmp.shl(CharWidth - BitsInPreviousByte);
- }
-
- // 'or' in the bits that go into the previous byte.
- llvm::Value *LastElt = Elements.back();
- if (llvm::ConstantInt *Val = dyn_cast<llvm::ConstantInt>(LastElt))
- Tmp |= Val->getValue();
- else {
- assert(isa<llvm::UndefValue>(LastElt));
- // If there is an undef field that we're adding to, it can either be a
- // scalar undef (in which case, we just replace it with our field) or it
- // is an array. If it is an array, we have to pull one byte off the
- // array so that the other undef bytes stay around.
- if (!isa<llvm::IntegerType>(LastElt->getType())) {
- // The undef padding will be a multibyte array, create a new smaller
- // padding and then an hole for our i8 to get plopped into.
- assert(isa<llvm::ArrayType>(LastElt->getType()) &&
- "Expected array padding of undefs");
- llvm::ArrayType *AT = cast<llvm::ArrayType>(LastElt->getType());
- assert(AT->getElementType()->isIntegerTy(CharWidth) &&
- AT->getNumElements() != 0 &&
- "Expected non-empty array padding of undefs");
-
- // Remove the padding array.
- NextFieldOffsetInChars -= CharUnits::fromQuantity(AT->getNumElements());
- Elements.pop_back();
-
- // Add the padding back in two chunks.
- AppendPadding(CharUnits::fromQuantity(AT->getNumElements()-1));
- AppendPadding(CharUnits::One());
- assert(isa<llvm::UndefValue>(Elements.back()) &&
- Elements.back()->getType()->isIntegerTy(CharWidth) &&
- "Padding addition didn't work right");
- }
+ if (CanEmitArray) {
+ return EmitArrayConstant(CGM, ATy, CommonType, ATy->getNumElements(),
+ ArrayElements, Filler);
+ }
+
+ // Can't emit as an array, carry on to emit as a struct.
+ }
+
+ CharUnits DesiredSize = Utils.getSize(DesiredTy);
+ CharUnits Align = CharUnits::One();
+ for (llvm::Constant *C : Elems)
+ Align = std::max(Align, Utils.getAlignment(C));
+ CharUnits AlignedSize = Size.alignTo(Align);
+
+ bool Packed = false;
+ ArrayRef<llvm::Constant*> UnpackedElems = Elems;
+ llvm::SmallVector<llvm::Constant*, 32> UnpackedElemStorage;
+ if ((DesiredSize < AlignedSize && !AllowOversized) ||
+ DesiredSize.alignTo(Align) != DesiredSize) {
+ // The natural layout would be the wrong size; force use of a packed layout.
+ NaturalLayout = false;
+ Packed = true;
+ } else if (DesiredSize > AlignedSize) {
+ // The constant would be too small. Add padding to fix it.
+ UnpackedElemStorage.assign(Elems.begin(), Elems.end());
+ UnpackedElemStorage.push_back(Utils.getPadding(DesiredSize - Size));
+ UnpackedElems = UnpackedElemStorage;
+ }
+
+ // If we don't have a natural layout, insert padding as necessary.
+ // As we go, double-check to see if we can actually just emit Elems
+ // as a non-packed struct and do so opportunistically if possible.
+ llvm::SmallVector<llvm::Constant*, 32> PackedElems;
+ if (!NaturalLayout) {
+ CharUnits SizeSoFar = CharUnits::Zero();
+ for (size_t I = 0; I != Elems.size(); ++I) {
+ CharUnits Align = Utils.getAlignment(Elems[I]);
+ CharUnits NaturalOffset = SizeSoFar.alignTo(Align);
+ CharUnits DesiredOffset = Offset(I);
+ assert(DesiredOffset >= SizeSoFar && "elements out of order");
+
+ if (DesiredOffset != NaturalOffset)
+ Packed = true;
+ if (DesiredOffset != SizeSoFar)
+ PackedElems.push_back(Utils.getPadding(DesiredOffset - SizeSoFar));
+ PackedElems.push_back(Elems[I]);
+ SizeSoFar = DesiredOffset + Utils.getSize(Elems[I]);
+ }
+ // If we're using the packed layout, pad it out to the desired size if
+ // necessary.
+ if (Packed) {
+ assert((SizeSoFar <= DesiredSize || AllowOversized) &&
+ "requested size is too small for contents");
+ if (SizeSoFar < DesiredSize)
+ PackedElems.push_back(Utils.getPadding(DesiredSize - SizeSoFar));
}
+ }
- Elements.back() = llvm::ConstantInt::get(CGM.getLLVMContext(), Tmp);
+ llvm::StructType *STy = llvm::ConstantStruct::getTypeForElements(
+ CGM.getLLVMContext(), Packed ? PackedElems : UnpackedElems, Packed);
- if (FitsCompletelyInPreviousByte)
- return;
+ // Pick the type to use. If the type is layout identical to the desired
+ // type then use it, otherwise use whatever the builder produced for us.
+ if (llvm::StructType *DesiredSTy = dyn_cast<llvm::StructType>(DesiredTy)) {
+ if (DesiredSTy->isLayoutIdentical(STy))
+ STy = DesiredSTy;
}
- while (FieldValue.getBitWidth() > CharWidth) {
- llvm::APInt Tmp;
+ return llvm::ConstantStruct::get(STy, Packed ? PackedElems : UnpackedElems);
+}
- if (CGM.getDataLayout().isBigEndian()) {
- // We want the high bits.
- Tmp =
- FieldValue.lshr(FieldValue.getBitWidth() - CharWidth).trunc(CharWidth);
- } else {
- // We want the low bits.
- Tmp = FieldValue.trunc(CharWidth);
+void ConstantAggregateBuilder::condense(CharUnits Offset,
+ llvm::Type *DesiredTy) {
+ CharUnits Size = getSize(DesiredTy);
- FieldValue.lshrInPlace(CharWidth);
- }
+ llvm::Optional<size_t> FirstElemToReplace = splitAt(Offset);
+ if (!FirstElemToReplace)
+ return;
+ size_t First = *FirstElemToReplace;
- Elements.push_back(llvm::ConstantInt::get(CGM.getLLVMContext(), Tmp));
- ++NextFieldOffsetInChars;
+ llvm::Optional<size_t> LastElemToReplace = splitAt(Offset + Size);
+ if (!LastElemToReplace)
+ return;
+ size_t Last = *LastElemToReplace;
+
+ size_t Length = Last - First;
+ if (Length == 0)
+ return;
- FieldValue = FieldValue.trunc(FieldValue.getBitWidth() - CharWidth);
+ if (Length == 1 && Offsets[First] == Offset &&
+ getSize(Elems[First]) == Size) {
+ // Re-wrap single element structs if necessary. Otherwise, leave any single
+ // element constant of the right size alone even if it has the wrong type.
+ auto *STy = dyn_cast<llvm::StructType>(DesiredTy);
+ if (STy && STy->getNumElements() == 1 &&
+ STy->getElementType(0) == Elems[First]->getType())
+ Elems[First] = llvm::ConstantStruct::get(STy, Elems[First]);
+ return;
}
- assert(FieldValue.getBitWidth() > 0 &&
- "Should have at least one bit left!");
- assert(FieldValue.getBitWidth() <= CharWidth &&
- "Should not have more than a byte left!");
+ llvm::Constant *Replacement = buildFrom(
+ CGM, makeArrayRef(Elems).slice(First, Length),
+ makeArrayRef(Offsets).slice(First, Length), Offset, getSize(DesiredTy),
+ /*known to have natural layout=*/false, DesiredTy, false);
+ replace(Elems, First, Last, {Replacement});
+ replace(Offsets, First, Last, {Offset});
+}
- if (FieldValue.getBitWidth() < CharWidth) {
- if (CGM.getDataLayout().isBigEndian()) {
- unsigned BitWidth = FieldValue.getBitWidth();
+//===----------------------------------------------------------------------===//
+// ConstStructBuilder
+//===----------------------------------------------------------------------===//
- FieldValue = FieldValue.zext(CharWidth) << (CharWidth - BitWidth);
- } else
- FieldValue = FieldValue.zext(CharWidth);
- }
+class ConstStructBuilder {
+ CodeGenModule &CGM;
+ ConstantEmitter &Emitter;
+ ConstantAggregateBuilder &Builder;
+ CharUnits StartOffset;
- // Append the last element.
- Elements.push_back(llvm::ConstantInt::get(CGM.getLLVMContext(),
- FieldValue));
- ++NextFieldOffsetInChars;
-}
+public:
+ static llvm::Constant *BuildStruct(ConstantEmitter &Emitter,
+ InitListExpr *ILE, QualType StructTy);
+ static llvm::Constant *BuildStruct(ConstantEmitter &Emitter,
+ const APValue &Value, QualType ValTy);
+ static bool UpdateStruct(ConstantEmitter &Emitter,
+ ConstantAggregateBuilder &Const, CharUnits Offset,
+ InitListExpr *Updater);
-void ConstStructBuilder::AppendPadding(CharUnits PadSize) {
- if (PadSize.isZero())
- return;
+private:
+ ConstStructBuilder(ConstantEmitter &Emitter,
+ ConstantAggregateBuilder &Builder, CharUnits StartOffset)
+ : CGM(Emitter.CGM), Emitter(Emitter), Builder(Builder),
+ StartOffset(StartOffset) {}
- llvm::Type *Ty = CGM.Int8Ty;
- if (PadSize > CharUnits::One())
- Ty = llvm::ArrayType::get(Ty, PadSize.getQuantity());
+ bool AppendField(const FieldDecl *Field, uint64_t FieldOffset,
+ llvm::Constant *InitExpr, bool AllowOverwrite = false);
- llvm::Constant *C = llvm::UndefValue::get(Ty);
- Elements.push_back(C);
- assert(getAlignment(C) == CharUnits::One() &&
- "Padding must have 1 byte alignment!");
+ bool AppendBytes(CharUnits FieldOffsetInChars, llvm::Constant *InitCst,
+ bool AllowOverwrite = false);
- NextFieldOffsetInChars += getSizeInChars(C);
-}
+ bool AppendBitField(const FieldDecl *Field, uint64_t FieldOffset,
+ llvm::ConstantInt *InitExpr, bool AllowOverwrite = false);
-void ConstStructBuilder::AppendTailPadding(CharUnits RecordSize) {
- assert(NextFieldOffsetInChars <= RecordSize &&
- "Size mismatch!");
+ bool Build(InitListExpr *ILE, bool AllowOverwrite);
+ bool Build(const APValue &Val, const RecordDecl *RD, bool IsPrimaryBase,
+ const CXXRecordDecl *VTableClass, CharUnits BaseOffset);
+ llvm::Constant *Finalize(QualType Ty);
+};
- AppendPadding(RecordSize - NextFieldOffsetInChars);
-}
+bool ConstStructBuilder::AppendField(
+ const FieldDecl *Field, uint64_t FieldOffset, llvm::Constant *InitCst,
+ bool AllowOverwrite) {
+ const ASTContext &Context = CGM.getContext();
-void ConstStructBuilder::ConvertStructToPacked() {
- SmallVector<llvm::Constant *, 16> PackedElements;
- CharUnits ElementOffsetInChars = CharUnits::Zero();
+ CharUnits FieldOffsetInChars = Context.toCharUnitsFromBits(FieldOffset);
- for (unsigned i = 0, e = Elements.size(); i != e; ++i) {
- llvm::Constant *C = Elements[i];
+ return AppendBytes(FieldOffsetInChars, InitCst, AllowOverwrite);
+}
- CharUnits ElementAlign = CharUnits::fromQuantity(
- CGM.getDataLayout().getABITypeAlignment(C->getType()));
- CharUnits AlignedElementOffsetInChars =
- ElementOffsetInChars.alignTo(ElementAlign);
+bool ConstStructBuilder::AppendBytes(CharUnits FieldOffsetInChars,
+ llvm::Constant *InitCst,
+ bool AllowOverwrite) {
+ return Builder.add(InitCst, StartOffset + FieldOffsetInChars, AllowOverwrite);
+}
- if (AlignedElementOffsetInChars > ElementOffsetInChars) {
- // We need some padding.
- CharUnits NumChars =
- AlignedElementOffsetInChars - ElementOffsetInChars;
+bool ConstStructBuilder::AppendBitField(
+ const FieldDecl *Field, uint64_t FieldOffset, llvm::ConstantInt *CI,
+ bool AllowOverwrite) {
+ uint64_t FieldSize = Field->getBitWidthValue(CGM.getContext());
+ llvm::APInt FieldValue = CI->getValue();
- llvm::Type *Ty = CGM.Int8Ty;
- if (NumChars > CharUnits::One())
- Ty = llvm::ArrayType::get(Ty, NumChars.getQuantity());
+ // Promote the size of FieldValue if necessary
+ // FIXME: This should never occur, but currently it can because initializer
+ // constants are cast to bool, and because clang is not enforcing bitfield
+ // width limits.
+ if (FieldSize > FieldValue.getBitWidth())
+ FieldValue = FieldValue.zext(FieldSize);
- llvm::Constant *Padding = llvm::UndefValue::get(Ty);
- PackedElements.push_back(Padding);
- ElementOffsetInChars += getSizeInChars(Padding);
- }
+ // Truncate the size of FieldValue to the bit field size.
+ if (FieldSize < FieldValue.getBitWidth())
+ FieldValue = FieldValue.trunc(FieldSize);
- PackedElements.push_back(C);
- ElementOffsetInChars += getSizeInChars(C);
+ return Builder.addBits(FieldValue,
+ CGM.getContext().toBits(StartOffset) + FieldOffset,
+ AllowOverwrite);
+}
+
+static bool EmitDesignatedInitUpdater(ConstantEmitter &Emitter,
+ ConstantAggregateBuilder &Const,
+ CharUnits Offset, QualType Type,
+ InitListExpr *Updater) {
+ if (Type->isRecordType())
+ return ConstStructBuilder::UpdateStruct(Emitter, Const, Offset, Updater);
+
+ auto CAT = Emitter.CGM.getContext().getAsConstantArrayType(Type);
+ if (!CAT)
+ return false;
+ QualType ElemType = CAT->getElementType();
+ CharUnits ElemSize = Emitter.CGM.getContext().getTypeSizeInChars(ElemType);
+ llvm::Type *ElemTy = Emitter.CGM.getTypes().ConvertTypeForMem(ElemType);
+
+ llvm::Constant *FillC = nullptr;
+ if (Expr *Filler = Updater->getArrayFiller()) {
+ if (!isa<NoInitExpr>(Filler)) {
+ FillC = Emitter.tryEmitAbstractForMemory(Filler, ElemType);
+ if (!FillC)
+ return false;
+ }
}
- assert(ElementOffsetInChars == NextFieldOffsetInChars &&
- "Packing the struct changed its size!");
+ unsigned NumElementsToUpdate =
+ FillC ? CAT->getSize().getZExtValue() : Updater->getNumInits();
+ for (unsigned I = 0; I != NumElementsToUpdate; ++I, Offset += ElemSize) {
+ Expr *Init = nullptr;
+ if (I < Updater->getNumInits())
+ Init = Updater->getInit(I);
- Elements.swap(PackedElements);
- LLVMStructAlignment = CharUnits::One();
- Packed = true;
+ if (!Init && FillC) {
+ if (!Const.add(FillC, Offset, true))
+ return false;
+ } else if (!Init || isa<NoInitExpr>(Init)) {
+ continue;
+ } else if (InitListExpr *ChildILE = dyn_cast<InitListExpr>(Init)) {
+ if (!EmitDesignatedInitUpdater(Emitter, Const, Offset, ElemType,
+ ChildILE))
+ return false;
+ // Attempt to reduce the array element to a single constant if necessary.
+ Const.condense(Offset, ElemTy);
+ } else {
+ llvm::Constant *Val = Emitter.tryEmitPrivateForMemory(Init, ElemType);
+ if (!Const.add(Val, Offset, true))
+ return false;
+ }
+ }
+
+ return true;
}
-bool ConstStructBuilder::Build(InitListExpr *ILE) {
+bool ConstStructBuilder::Build(InitListExpr *ILE, bool AllowOverwrite) {
RecordDecl *RD = ILE->getType()->getAs<RecordType>()->getDecl();
const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
- unsigned FieldNo = 0;
+ unsigned FieldNo = -1;
unsigned ElementNo = 0;
// Bail out if we have base classes. We could support these, but they only
@@ -378,10 +671,11 @@
if (CXXRD->getNumBases())
return false;
- for (RecordDecl::field_iterator Field = RD->field_begin(),
- FieldEnd = RD->field_end(); Field != FieldEnd; ++Field, ++FieldNo) {
+ for (FieldDecl *Field : RD->fields()) {
+ ++FieldNo;
+
// If this is a union, skip all the fields that aren't being initialized.
- if (RD->isUnion() && ILE->getInitializedFieldInUnion() != *Field)
+ if (RD->isUnion() && ILE->getInitializedFieldInUnion() != Field)
continue;
// Don't emit anonymous bitfields, they just affect layout.
@@ -390,23 +684,48 @@
// Get the initializer. A struct can include fields without initializers,
// we just use explicit null values for them.
- llvm::Constant *EltInit;
+ Expr *Init = nullptr;
if (ElementNo < ILE->getNumInits())
- EltInit = Emitter.tryEmitPrivateForMemory(ILE->getInit(ElementNo++),
- Field->getType());
- else
- EltInit = Emitter.emitNullForMemory(Field->getType());
+ Init = ILE->getInit(ElementNo++);
+ if (Init && isa<NoInitExpr>(Init))
+ continue;
+
+ // When emitting a DesignatedInitUpdateExpr, a nested InitListExpr
+ // represents additional overwriting of our current constant value, and not
+ // a new constant to emit independently.
+ if (AllowOverwrite &&
+ (Field->getType()->isArrayType() || Field->getType()->isRecordType())) {
+ if (auto *SubILE = dyn_cast<InitListExpr>(Init)) {
+ CharUnits Offset = CGM.getContext().toCharUnitsFromBits(
+ Layout.getFieldOffset(FieldNo));
+ if (!EmitDesignatedInitUpdater(Emitter, Builder, StartOffset + Offset,
+ Field->getType(), SubILE))
+ return false;
+ // If we split apart the field's value, try to collapse it down to a
+ // single value now.
+ Builder.condense(StartOffset + Offset,
+ CGM.getTypes().ConvertTypeForMem(Field->getType()));
+ continue;
+ }
+ }
+ llvm::Constant *EltInit =
+ Init ? Emitter.tryEmitPrivateForMemory(Init, Field->getType())
+ : Emitter.emitNullForMemory(Field->getType());
if (!EltInit)
return false;
if (!Field->isBitField()) {
// Handle non-bitfield members.
- AppendField(*Field, Layout.getFieldOffset(FieldNo), EltInit);
+ if (!AppendField(Field, Layout.getFieldOffset(FieldNo), EltInit,
+ AllowOverwrite))
+ return false;
} else {
// Otherwise we have a bitfield.
if (auto *CI = dyn_cast<llvm::ConstantInt>(EltInit)) {
- AppendBitField(*Field, Layout.getFieldOffset(FieldNo), CI);
+ if (!AppendBitField(Field, Layout.getFieldOffset(FieldNo), CI,
+ AllowOverwrite))
+ return false;
} else {
// We are trying to initialize a bitfield with a non-trivial constant,
// this must require run-time code.
@@ -444,7 +763,8 @@
llvm::Constant *VTableAddressPoint =
CGM.getCXXABI().getVTableAddressPointForConstExpr(
BaseSubobject(CD, Offset), VTableClass);
- AppendBytes(Offset, VTableAddressPoint);
+ if (!AppendBytes(Offset, VTableAddressPoint))
+ return false;
}
// Accumulate and sort bases, in order to visit them in address order, which
@@ -493,93 +813,33 @@
if (!Field->isBitField()) {
// Handle non-bitfield members.
- AppendField(*Field, Layout.getFieldOffset(FieldNo) + OffsetBits, EltInit);
+ if (!AppendField(*Field, Layout.getFieldOffset(FieldNo) + OffsetBits,
+ EltInit))
+ return false;
} else {
// Otherwise we have a bitfield.
- AppendBitField(*Field, Layout.getFieldOffset(FieldNo) + OffsetBits,
- cast<llvm::ConstantInt>(EltInit));
+ if (!AppendBitField(*Field, Layout.getFieldOffset(FieldNo) + OffsetBits,
+ cast<llvm::ConstantInt>(EltInit)))
+ return false;
}
}
return true;
}
-llvm::Constant *ConstStructBuilder::Finalize(QualType Ty) {
- RecordDecl *RD = Ty->getAs<RecordType>()->getDecl();
- const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
-
- CharUnits LayoutSizeInChars = Layout.getSize();
-
- if (NextFieldOffsetInChars > LayoutSizeInChars) {
- // If the struct is bigger than the size of the record type,
- // we must have a flexible array member at the end.
- assert(RD->hasFlexibleArrayMember() &&
- "Must have flexible array member if struct is bigger than type!");
-
- // No tail padding is necessary.
- } else {
- // Append tail padding if necessary.
- CharUnits LLVMSizeInChars =
- NextFieldOffsetInChars.alignTo(LLVMStructAlignment);
-
- if (LLVMSizeInChars != LayoutSizeInChars)
- AppendTailPadding(LayoutSizeInChars);
-
- LLVMSizeInChars = NextFieldOffsetInChars.alignTo(LLVMStructAlignment);
-
- // Check if we need to convert the struct to a packed struct.
- if (NextFieldOffsetInChars <= LayoutSizeInChars &&
- LLVMSizeInChars > LayoutSizeInChars) {
- assert(!Packed && "Size mismatch!");
-
- ConvertStructToPacked();
- assert(NextFieldOffsetInChars <= LayoutSizeInChars &&
- "Converting to packed did not help!");
- }
-
- LLVMSizeInChars = NextFieldOffsetInChars.alignTo(LLVMStructAlignment);
-
- assert(LayoutSizeInChars == LLVMSizeInChars &&
- "Tail padding mismatch!");
- }
-
- // Pick the type to use. If the type is layout identical to the ConvertType
- // type then use it, otherwise use whatever the builder produced for us.
- llvm::StructType *STy =
- llvm::ConstantStruct::getTypeForElements(CGM.getLLVMContext(),
- Elements, Packed);
- llvm::Type *ValTy = CGM.getTypes().ConvertType(Ty);
- if (llvm::StructType *ValSTy = dyn_cast<llvm::StructType>(ValTy)) {
- if (ValSTy->isLayoutIdentical(STy))
- STy = ValSTy;
- }
-
- llvm::Constant *Result = llvm::ConstantStruct::get(STy, Elements);
-
- assert(NextFieldOffsetInChars.alignTo(getAlignment(Result)) ==
- getSizeInChars(Result) &&
- "Size mismatch!");
-
- return Result;
-}
-
-llvm::Constant *ConstStructBuilder::BuildStruct(ConstantEmitter &Emitter,
- ConstExprEmitter *ExprEmitter,
- llvm::Constant *Base,
- InitListExpr *Updater,
- QualType ValTy) {
- ConstStructBuilder Builder(Emitter);
- if (!Builder.Build(ExprEmitter, Base, Updater))
- return nullptr;
- return Builder.Finalize(ValTy);
+llvm::Constant *ConstStructBuilder::Finalize(QualType Type) {
+ RecordDecl *RD = Type->getAs<RecordType>()->getDecl();
+ llvm::Type *ValTy = CGM.getTypes().ConvertType(Type);
+ return Builder.build(ValTy, RD->hasFlexibleArrayMember());
}
llvm::Constant *ConstStructBuilder::BuildStruct(ConstantEmitter &Emitter,
InitListExpr *ILE,
QualType ValTy) {
- ConstStructBuilder Builder(Emitter);
+ ConstantAggregateBuilder Const(Emitter.CGM);
+ ConstStructBuilder Builder(Emitter, Const, CharUnits::Zero());
- if (!Builder.Build(ILE))
+ if (!Builder.Build(ILE, /*AllowOverwrite*/false))
return nullptr;
return Builder.Finalize(ValTy);
@@ -588,7 +848,8 @@
llvm::Constant *ConstStructBuilder::BuildStruct(ConstantEmitter &Emitter,
const APValue &Val,
QualType ValTy) {
- ConstStructBuilder Builder(Emitter);
+ ConstantAggregateBuilder Const(Emitter.CGM);
+ ConstStructBuilder Builder(Emitter, Const, CharUnits::Zero());
const RecordDecl *RD = ValTy->castAs<RecordType>()->getDecl();
const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD);
@@ -598,6 +859,12 @@
return Builder.Finalize(ValTy);
}
+bool ConstStructBuilder::UpdateStruct(ConstantEmitter &Emitter,
+ ConstantAggregateBuilder &Const,
+ CharUnits Offset, InitListExpr *Updater) {
+ return ConstStructBuilder(Emitter, Const, Offset)
+ .Build(Updater, /*AllowOverwrite*/ true);
+}
//===----------------------------------------------------------------------===//
// ConstExprEmitter
@@ -635,7 +902,7 @@
}
static llvm::Constant *
-EmitArrayConstant(CodeGenModule &CGM, const ConstantArrayType *DestType,
+EmitArrayConstant(CodeGenModule &CGM, llvm::ArrayType *DesiredType,
llvm::Type *CommonElementType, unsigned ArrayBound,
SmallVectorImpl<llvm::Constant *> &Elements,
llvm::Constant *Filler) {
@@ -648,10 +915,8 @@
--NonzeroLength;
}
- if (NonzeroLength == 0) {
- return llvm::ConstantAggregateZero::get(
- CGM.getTypes().ConvertType(QualType(DestType, 0)));
- }
+ if (NonzeroLength == 0)
+ return llvm::ConstantAggregateZero::get(DesiredType);
// Add a zeroinitializer array filler if we have lots of trailing zeroes.
unsigned TrailingZeroes = ArrayBound - NonzeroLength;
@@ -672,9 +937,7 @@
}
auto *FillerType =
- CommonElementType
- ? CommonElementType
- : CGM.getTypes().ConvertType(DestType->getElementType());
+ CommonElementType ? CommonElementType : DesiredType->getElementType();
FillerType = llvm::ArrayType::get(FillerType, TrailingZeroes);
Elements.back() = llvm::ConstantAggregateZero::get(FillerType);
CommonElementType = nullptr;
@@ -941,7 +1204,9 @@
Elts.push_back(C);
}
- return EmitArrayConstant(CGM, CAT, CommonElementType, NumElements, Elts,
+ llvm::ArrayType *Desired =
+ cast<llvm::ArrayType>(CGM.getTypes().ConvertType(ILE->getType()));
+ return EmitArrayConstant(CGM, Desired, CommonElementType, NumElements, Elts,
fillC);
}
@@ -967,80 +1232,24 @@
return nullptr;
}
- llvm::Constant *EmitDesignatedInitUpdater(llvm::Constant *Base,
- InitListExpr *Updater,
- QualType destType) {
- if (auto destAT = CGM.getContext().getAsArrayType(destType)) {
- llvm::ArrayType *AType = cast<llvm::ArrayType>(ConvertType(destType));
- llvm::Type *ElemType = AType->getElementType();
-
- unsigned NumInitElements = Updater->getNumInits();
- unsigned NumElements = AType->getNumElements();
-
- std::vector<llvm::Constant *> Elts;
- Elts.reserve(NumElements);
-
- QualType destElemType = destAT->getElementType();
-
- if (auto DataArray = dyn_cast<llvm::ConstantDataArray>(Base))
- for (unsigned i = 0; i != NumElements; ++i)
- Elts.push_back(DataArray->getElementAsConstant(i));
- else if (auto Array = dyn_cast<llvm::ConstantArray>(Base))
- for (unsigned i = 0; i != NumElements; ++i)
- Elts.push_back(Array->getOperand(i));
- else
- return nullptr; // FIXME: other array types not implemented
-
- llvm::Constant *fillC = nullptr;
- if (Expr *filler = Updater->getArrayFiller())
- if (!isa<NoInitExpr>(filler))
- fillC = Emitter.tryEmitAbstractForMemory(filler, destElemType);
- bool RewriteType = (fillC && fillC->getType() != ElemType);
-
- for (unsigned i = 0; i != NumElements; ++i) {
- Expr *Init = nullptr;
- if (i < NumInitElements)
- Init = Updater->getInit(i);
-
- if (!Init && fillC)
- Elts[i] = fillC;
- else if (!Init || isa<NoInitExpr>(Init))
- ; // Do nothing.
- else if (InitListExpr *ChildILE = dyn_cast<InitListExpr>(Init))
- Elts[i] = EmitDesignatedInitUpdater(Elts[i], ChildILE, destElemType);
- else
- Elts[i] = Emitter.tryEmitPrivateForMemory(Init, destElemType);
-
- if (!Elts[i])
- return nullptr;
- RewriteType |= (Elts[i]->getType() != ElemType);
- }
-
- if (RewriteType) {
- std::vector<llvm::Type *> Types;
- Types.reserve(NumElements);
- for (unsigned i = 0; i != NumElements; ++i)
- Types.push_back(Elts[i]->getType());
- llvm::StructType *SType = llvm::StructType::get(AType->getContext(),
- Types, true);
- return llvm::ConstantStruct::get(SType, Elts);
- }
-
- return llvm::ConstantArray::get(AType, Elts);
- }
-
- if (destType->isRecordType())
- return ConstStructBuilder::BuildStruct(Emitter, this, Base, Updater,
- destType);
-
- return nullptr;
- }
-
llvm::Constant *VisitDesignatedInitUpdateExpr(DesignatedInitUpdateExpr *E,
QualType destType) {
auto C = Visit(E->getBase(), destType);
- if (!C) return nullptr;
- return EmitDesignatedInitUpdater(C, E->getUpdater(), destType);
+ if (!C)
+ return nullptr;
+
+ ConstantAggregateBuilder Const(CGM);
+ Const.add(C, CharUnits::Zero(), false);
+
+ if (!EmitDesignatedInitUpdater(Emitter, Const, CharUnits::Zero(), destType,
+ E->getUpdater()))
+ return nullptr;
+
+ llvm::Type *ValTy = CGM.getTypes().ConvertType(destType);
+ bool HasFlexibleArray = false;
+ if (auto *RT = destType->getAs<RecordType>())
+ HasFlexibleArray = RT->getDecl()->hasFlexibleArrayMember();
+ return Const.build(ValTy, HasFlexibleArray);
}
llvm::Constant *VisitCXXConstructExpr(CXXConstructExpr *E, QualType Ty) {
@@ -1106,76 +1315,6 @@
} // end anonymous namespace.
-bool ConstStructBuilder::Build(ConstExprEmitter *ExprEmitter,
- llvm::Constant *Base,
- InitListExpr *Updater) {
- assert(Base && "base expression should not be empty");
-
- QualType ExprType = Updater->getType();
- RecordDecl *RD = ExprType->getAs<RecordType>()->getDecl();
- const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
- const llvm::StructLayout *BaseLayout = CGM.getDataLayout().getStructLayout(
- cast<llvm::StructType>(Base->getType()));
- unsigned FieldNo = -1;
- unsigned ElementNo = 0;
-
- // Bail out if we have base classes. We could support these, but they only
- // arise in C++1z where we will have already constant folded most interesting
- // cases. FIXME: There are still a few more cases we can handle this way.
- if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD))
- if (CXXRD->getNumBases())
- return false;
-
- for (FieldDecl *Field : RD->fields()) {
- ++FieldNo;
-
- if (RD->isUnion() && Updater->getInitializedFieldInUnion() != Field)
- continue;
-
- // Skip anonymous bitfields.
- if (Field->isUnnamedBitfield())
- continue;
-
- llvm::Constant *EltInit = Base->getAggregateElement(ElementNo);
-
- // Bail out if the type of the ConstantStruct does not have the same layout
- // as the type of the InitListExpr.
- if (CGM.getTypes().ConvertType(Field->getType()) != EltInit->getType() ||
- Layout.getFieldOffset(ElementNo) !=
- BaseLayout->getElementOffsetInBits(ElementNo))
- return false;
-
- // Get the initializer. If we encounter an empty field or a NoInitExpr,
- // we use values from the base expression.
- Expr *Init = nullptr;
- if (ElementNo < Updater->getNumInits())
- Init = Updater->getInit(ElementNo);
-
- if (!Init || isa<NoInitExpr>(Init))
- ; // Do nothing.
- else if (InitListExpr *ChildILE = dyn_cast<InitListExpr>(Init))
- EltInit = ExprEmitter->EmitDesignatedInitUpdater(EltInit, ChildILE,
- Field->getType());
- else
- EltInit = Emitter.tryEmitPrivateForMemory(Init, Field->getType());
-
- ++ElementNo;
-
- if (!EltInit)
- return false;
-
- if (!Field->isBitField())
- AppendField(Field, Layout.getFieldOffset(FieldNo), EltInit);
- else if (llvm::ConstantInt *CI = dyn_cast<llvm::ConstantInt>(EltInit))
- AppendBitField(Field, Layout.getFieldOffset(FieldNo), CI);
- else
- // Initializing a bitfield with a non-trivial constant?
- return false;
- }
-
- return true;
-}
-
llvm::Constant *ConstantEmitter::validateAndPopAbstract(llvm::Constant *C,
AbstractState saved) {
Abstract = saved.OldValue;
@@ -1988,7 +2127,9 @@
return llvm::ConstantAggregateZero::get(AType);
}
- return EmitArrayConstant(CGM, CAT, CommonElementType, NumElements, Elts,
+ llvm::ArrayType *Desired =
+ cast<llvm::ArrayType>(CGM.getTypes().ConvertType(DestType));
+ return EmitArrayConstant(CGM, Desired, CommonElementType, NumElements, Elts,
Filler);
}
case APValue::MemberPointer:
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