================
@@ -21,20 +20,526 @@
#include "clang/AST/APValue.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/Attr.h"
+#include "clang/AST/CharUnits.h"
#include "clang/AST/OperationKinds.h"
#include "clang/AST/RecordLayout.h"
#include "clang/AST/StmtVisitor.h"
#include "clang/Basic/Builtins.h"
-#include "clang/Basic/Specifiers.h"
#include "clang/CIR/Dialect/IR/CIRAttrs.h"
#include "clang/CIR/Dialect/IR/CIRTypes.h"
+#include "clang/CIR/MissingFeatures.h"
#include "llvm/ADT/STLExtras.h"
-#include "llvm/ADT/Sequence.h"
#include "llvm/Support/ErrorHandling.h"
+#include <iterator>
using namespace clang;
using namespace clang::CIRGen;
+//===----------------------------------------------------------------------===//
+// ConstantAggregateBuilder
+//===----------------------------------------------------------------------===//
+
+namespace {
+class ConstExprEmitter;
+
+static mlir::TypedAttr computePadding(CIRGenModule &cgm, CharUnits size) {
+ mlir::Type eltTy = cgm.UCharTy;
+ clang::CharUnits::QuantityType arSize = size.getQuantity();
+ CIRGenBuilderTy &bld = cgm.getBuilder();
+ if (size > CharUnits::One()) {
+ SmallVector<mlir::Attribute, 4> elts(arSize, cir::ZeroAttr::get(eltTy));
+ return bld.getConstArray(mlir::ArrayAttr::get(bld.getContext(), elts),
+ cir::ArrayType::get(eltTy, arSize));
+ }
+
+ return cir::ZeroAttr::get(eltTy);
+}
+
+static mlir::Attribute
+emitArrayConstant(CIRGenModule &cgm, mlir::Type desiredType,
+ mlir::Type commonElementType, unsigned arrayBound,
+ SmallVectorImpl<mlir::TypedAttr> &elements,
+ mlir::TypedAttr filler);
+
+struct ConstantAggregateBuilderUtils {
+ CIRGenModule &cgm;
+ cir::CIRDataLayout dataLayout;
+
+ ConstantAggregateBuilderUtils(CIRGenModule &cgm)
+ : cgm(cgm), dataLayout{cgm.getModule()} {}
+
+ CharUnits getAlignment(const mlir::TypedAttr c) const {
+ return CharUnits::fromQuantity(
+ dataLayout.getAlignment(c.getType(), /*abiOrPref=*/true));
+ }
+
+ CharUnits getSize(mlir::Type ty) const {
+ return CharUnits::fromQuantity(dataLayout.getTypeAllocSize(ty));
+ }
+
+ CharUnits getSize(const mlir::TypedAttr c) const {
+ return getSize(c.getType());
+ }
+
+ mlir::TypedAttr getPadding(CharUnits size) const {
+ return computePadding(cgm, size);
+ }
+};
+
+/// Incremental builder for an mlir::TypedAttr holding a record 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<mlir::TypedAttr, 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;
+
+ static mlir::Attribute
+ buildFrom(CIRGenModule &cgm, ArrayRef<mlir::TypedAttr> elems,
+ ArrayRef<CharUnits> offsets, CharUnits startOffset, CharUnits size,
+ bool naturalLayout, mlir::Type desiredTy, bool allowOversized);
+
+public:
+ ConstantAggregateBuilder(CIRGenModule &cgm)
+ : ConstantAggregateBuilderUtils(cgm) {}
+
+ /// 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(mlir::TypedAttr typedAttr, 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);
+
+ /// 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.
+ mlir::Attribute build(mlir::Type desiredTy, bool allowOversized) const {
+ return buildFrom(cgm, elems, offsets, CharUnits::Zero(), size,
+ naturalLayout, desiredTy, allowOversized);
+ }
+};
+
+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(mlir::TypedAttr typedAttr, CharUnits offset,
+ bool allowOverwrite) {
+ // Common case: appending to a layout.
+ if (offset >= size) {
+ CharUnits align = getAlignment(typedAttr);
+ 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(typedAttr);
+ offsets.push_back(offset);
+ size = offset + getSize(typedAttr);
+ return true;
+ }
+
+ // Uncommon case: constant overlaps what we've already created.
+ cgm.errorNYI("overlapping constants");
+ return false;
+}
+
+mlir::Attribute ConstantAggregateBuilder::buildFrom(
+ CIRGenModule &cgm, ArrayRef<mlir::TypedAttr> elems,
+ ArrayRef<CharUnits> offsets, CharUnits startOffset, CharUnits size,
+ bool naturalLayout, mlir::Type desiredTy, bool allowOversized) {
+ ConstantAggregateBuilderUtils utils(cgm);
+
+ if (elems.empty())
+ return cir::UndefAttr::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 (mlir::isa<cir::ArrayType>(desiredTy)) {
+ cgm.errorNYI("array aggregate constants");
+ return {};
+ }
+
+ // The size of the constant we plan to generate. This is usually just the
size
+ // of the initialized type, but in AllowOversized mode (i.e. flexible array
+ // init), it can be larger.
+ CharUnits desiredSize = utils.getSize(desiredTy);
+ if (size > desiredSize) {
+ assert(allowOversized && "Elems are oversized");
+ desiredSize = size;
+ }
+
+ // The natural alignment of an unpacked CIR record with the given elements.
+ CharUnits align = CharUnits::One();
+ for (mlir::TypedAttr e : elems) {
+ align = std::max(align, utils.getAlignment(e));
+ }
+
+ // The natural size of an unpacked LLVM struct with the given elements.
+ CharUnits alignedSize = size.alignTo(align);
+
+ bool packed = false;
+ bool padded = false;
+ ArrayRef<mlir::TypedAttr> unpackedElems = elems;
+
+ llvm::SmallVector<mlir::TypedAttr, 32> unpackedElemStorage;
----------------
andykaylor wrote:
```suggestion
llvm::SmallVector<mlir::TypedAttr> unpackedElemStorage;
```
maybe? I think using 32 here will yield about double the default size, so maybe
that's been thought through.
https://github.com/llvm/llvm-project/pull/155663
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