mirror of
https://github.com/c64scene-ar/llvm-6502.git
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d7a4f74f15
The AAPCS treats small structs and homogeneous floating (or vector) aggregates specially, and guarantees they either get passed as a contiguous block of registers, or prevent any future use of those registers and get passed on the stack. This concept can fit quite neatly into LLVM's own type system, mapping an HFA to [N x float] and so on, and small structs to [N x i64]. Doing so allows front-ends to emit AAPCS compliant code without having to duplicate the register counting logic. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222903 91177308-0d34-0410-b5e6-96231b3b80d8
542 lines
18 KiB
C++
542 lines
18 KiB
C++
//===--------- llvm/DataLayout.h - Data size & alignment info ---*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines layout properties related to datatype size/offset/alignment
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// information. It uses lazy annotations to cache information about how
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// structure types are laid out and used.
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//
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// This structure should be created once, filled in if the defaults are not
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// correct and then passed around by const&. None of the members functions
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// require modification to the object.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_IR_DATALAYOUT_H
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#define LLVM_IR_DATALAYOUT_H
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/IR/DerivedTypes.h"
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#include "llvm/IR/Type.h"
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#include "llvm/Pass.h"
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#include "llvm/Support/DataTypes.h"
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// This needs to be outside of the namespace, to avoid conflict with llvm-c
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// decl.
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typedef struct LLVMOpaqueTargetData *LLVMTargetDataRef;
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namespace llvm {
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class Value;
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class Type;
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class IntegerType;
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class StructType;
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class StructLayout;
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class Triple;
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class GlobalVariable;
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class LLVMContext;
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template<typename T>
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class ArrayRef;
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/// Enum used to categorize the alignment types stored by LayoutAlignElem
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enum AlignTypeEnum {
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INVALID_ALIGN = 0,
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INTEGER_ALIGN = 'i',
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VECTOR_ALIGN = 'v',
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FLOAT_ALIGN = 'f',
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AGGREGATE_ALIGN = 'a'
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};
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/// \brief Layout alignment element.
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///
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/// Stores the alignment data associated with a given alignment type (integer,
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/// vector, float) and type bit width.
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///
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/// \note The unusual order of elements in the structure attempts to reduce
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/// padding and make the structure slightly more cache friendly.
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struct LayoutAlignElem {
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/// \brief Alignment type from \c AlignTypeEnum
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unsigned AlignType : 8;
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unsigned TypeBitWidth : 24;
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unsigned ABIAlign : 16;
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unsigned PrefAlign : 16;
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static LayoutAlignElem get(AlignTypeEnum align_type, unsigned abi_align,
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unsigned pref_align, uint32_t bit_width);
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bool operator==(const LayoutAlignElem &rhs) const;
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};
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/// \brief Layout pointer alignment element.
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///
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/// Stores the alignment data associated with a given pointer and address space.
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///
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/// \note The unusual order of elements in the structure attempts to reduce
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/// padding and make the structure slightly more cache friendly.
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struct PointerAlignElem {
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unsigned ABIAlign;
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unsigned PrefAlign;
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uint32_t TypeByteWidth;
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uint32_t AddressSpace;
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/// Initializer
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static PointerAlignElem get(uint32_t AddressSpace, unsigned ABIAlign,
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unsigned PrefAlign, uint32_t TypeByteWidth);
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bool operator==(const PointerAlignElem &rhs) const;
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};
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/// \brief A parsed version of the target data layout string in and methods for
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/// querying it.
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///
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/// The target data layout string is specified *by the target* - a frontend
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/// generating LLVM IR is required to generate the right target data for the
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/// target being codegen'd to.
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class DataLayout {
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private:
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/// Defaults to false.
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bool BigEndian;
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unsigned StackNaturalAlign;
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enum ManglingModeT { MM_None, MM_ELF, MM_MachO, MM_WINCOFF, MM_Mips };
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ManglingModeT ManglingMode;
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SmallVector<unsigned char, 8> LegalIntWidths;
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/// \brief Primitive type alignment data.
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SmallVector<LayoutAlignElem, 16> Alignments;
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typedef SmallVector<PointerAlignElem, 8> PointersTy;
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PointersTy Pointers;
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PointersTy::const_iterator
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findPointerLowerBound(uint32_t AddressSpace) const {
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return const_cast<DataLayout *>(this)->findPointerLowerBound(AddressSpace);
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}
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PointersTy::iterator findPointerLowerBound(uint32_t AddressSpace);
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/// This member is a signal that a requested alignment type and bit width were
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/// not found in the SmallVector.
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static const LayoutAlignElem InvalidAlignmentElem;
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/// This member is a signal that a requested pointer type and bit width were
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/// not found in the DenseSet.
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static const PointerAlignElem InvalidPointerElem;
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// The StructType -> StructLayout map.
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mutable void *LayoutMap;
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void setAlignment(AlignTypeEnum align_type, unsigned abi_align,
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unsigned pref_align, uint32_t bit_width);
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unsigned getAlignmentInfo(AlignTypeEnum align_type, uint32_t bit_width,
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bool ABIAlign, Type *Ty) const;
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void setPointerAlignment(uint32_t AddrSpace, unsigned ABIAlign,
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unsigned PrefAlign, uint32_t TypeByteWidth);
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/// Internal helper method that returns requested alignment for type.
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unsigned getAlignment(Type *Ty, bool abi_or_pref) const;
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/// \brief Valid alignment predicate.
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///
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/// Predicate that tests a LayoutAlignElem reference returned by get() against
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/// InvalidAlignmentElem.
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bool validAlignment(const LayoutAlignElem &align) const {
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return &align != &InvalidAlignmentElem;
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}
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/// \brief Valid pointer predicate.
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///
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/// Predicate that tests a PointerAlignElem reference returned by get()
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/// against \c InvalidPointerElem.
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bool validPointer(const PointerAlignElem &align) const {
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return &align != &InvalidPointerElem;
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}
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/// Parses a target data specification string. Assert if the string is
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/// malformed.
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void parseSpecifier(StringRef LayoutDescription);
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// Free all internal data structures.
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void clear();
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public:
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/// Constructs a DataLayout from a specification string. See reset().
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explicit DataLayout(StringRef LayoutDescription) : LayoutMap(nullptr) {
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reset(LayoutDescription);
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}
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/// Initialize target data from properties stored in the module.
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explicit DataLayout(const Module *M);
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void init(const Module *M);
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DataLayout(const DataLayout &DL) : LayoutMap(nullptr) { *this = DL; }
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DataLayout &operator=(const DataLayout &DL) {
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clear();
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BigEndian = DL.isBigEndian();
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StackNaturalAlign = DL.StackNaturalAlign;
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ManglingMode = DL.ManglingMode;
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LegalIntWidths = DL.LegalIntWidths;
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Alignments = DL.Alignments;
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Pointers = DL.Pointers;
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return *this;
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}
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bool operator==(const DataLayout &Other) const;
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bool operator!=(const DataLayout &Other) const { return !(*this == Other); }
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~DataLayout(); // Not virtual, do not subclass this class
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/// Parse a data layout string (with fallback to default values).
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void reset(StringRef LayoutDescription);
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/// Layout endianness...
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bool isLittleEndian() const { return !BigEndian; }
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bool isBigEndian() const { return BigEndian; }
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/// \brief Returns the string representation of the DataLayout.
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///
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/// This representation is in the same format accepted by the string
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/// constructor above.
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std::string getStringRepresentation() const;
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/// \brief Returns true if the specified type is known to be a native integer
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/// type supported by the CPU.
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///
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/// For example, i64 is not native on most 32-bit CPUs and i37 is not native
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/// on any known one. This returns false if the integer width is not legal.
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///
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/// The width is specified in bits.
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bool isLegalInteger(unsigned Width) const {
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for (unsigned LegalIntWidth : LegalIntWidths)
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if (LegalIntWidth == Width)
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return true;
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return false;
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}
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bool isIllegalInteger(unsigned Width) const { return !isLegalInteger(Width); }
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/// Returns true if the given alignment exceeds the natural stack alignment.
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bool exceedsNaturalStackAlignment(unsigned Align) const {
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return (StackNaturalAlign != 0) && (Align > StackNaturalAlign);
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}
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unsigned getStackAlignment() const { return StackNaturalAlign; }
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bool hasMicrosoftFastStdCallMangling() const {
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return ManglingMode == MM_WINCOFF;
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}
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bool hasLinkerPrivateGlobalPrefix() const { return ManglingMode == MM_MachO; }
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const char *getLinkerPrivateGlobalPrefix() const {
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if (ManglingMode == MM_MachO)
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return "l";
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return getPrivateGlobalPrefix();
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}
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char getGlobalPrefix() const {
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switch (ManglingMode) {
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case MM_None:
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case MM_ELF:
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case MM_Mips:
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return '\0';
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case MM_MachO:
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case MM_WINCOFF:
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return '_';
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}
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llvm_unreachable("invalid mangling mode");
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}
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const char *getPrivateGlobalPrefix() const {
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switch (ManglingMode) {
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case MM_None:
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return "";
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case MM_ELF:
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return ".L";
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case MM_Mips:
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return "$";
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case MM_MachO:
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case MM_WINCOFF:
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return "L";
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}
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llvm_unreachable("invalid mangling mode");
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}
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static const char *getManglingComponent(const Triple &T);
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/// \brief Returns true if the specified type fits in a native integer type
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/// supported by the CPU.
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///
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/// For example, if the CPU only supports i32 as a native integer type, then
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/// i27 fits in a legal integer type but i45 does not.
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bool fitsInLegalInteger(unsigned Width) const {
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for (unsigned LegalIntWidth : LegalIntWidths)
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if (Width <= LegalIntWidth)
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return true;
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return false;
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}
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/// Layout pointer alignment
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/// FIXME: The defaults need to be removed once all of
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/// the backends/clients are updated.
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unsigned getPointerABIAlignment(unsigned AS = 0) const;
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/// Return target's alignment for stack-based pointers
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/// FIXME: The defaults need to be removed once all of
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/// the backends/clients are updated.
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unsigned getPointerPrefAlignment(unsigned AS = 0) const;
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/// Layout pointer size
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/// FIXME: The defaults need to be removed once all of
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/// the backends/clients are updated.
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unsigned getPointerSize(unsigned AS = 0) const;
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/// Layout pointer size, in bits
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/// FIXME: The defaults need to be removed once all of
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/// the backends/clients are updated.
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unsigned getPointerSizeInBits(unsigned AS = 0) const {
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return getPointerSize(AS) * 8;
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}
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/// Layout pointer size, in bits, based on the type. If this function is
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/// called with a pointer type, then the type size of the pointer is returned.
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/// If this function is called with a vector of pointers, then the type size
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/// of the pointer is returned. This should only be called with a pointer or
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/// vector of pointers.
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unsigned getPointerTypeSizeInBits(Type *) const;
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unsigned getPointerTypeSize(Type *Ty) const {
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return getPointerTypeSizeInBits(Ty) / 8;
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}
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/// Size examples:
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///
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/// Type SizeInBits StoreSizeInBits AllocSizeInBits[*]
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/// ---- ---------- --------------- ---------------
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/// i1 1 8 8
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/// i8 8 8 8
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/// i19 19 24 32
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/// i32 32 32 32
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/// i100 100 104 128
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/// i128 128 128 128
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/// Float 32 32 32
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/// Double 64 64 64
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/// X86_FP80 80 80 96
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///
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/// [*] The alloc size depends on the alignment, and thus on the target.
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/// These values are for x86-32 linux.
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/// \brief Returns the number of bits necessary to hold the specified type.
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///
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/// For example, returns 36 for i36 and 80 for x86_fp80. The type passed must
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/// have a size (Type::isSized() must return true).
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uint64_t getTypeSizeInBits(Type *Ty) const;
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/// \brief Returns the maximum number of bytes that may be overwritten by
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/// storing the specified type.
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///
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/// For example, returns 5 for i36 and 10 for x86_fp80.
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uint64_t getTypeStoreSize(Type *Ty) const {
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return (getTypeSizeInBits(Ty) + 7) / 8;
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}
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/// \brief Returns the maximum number of bits that may be overwritten by
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/// storing the specified type; always a multiple of 8.
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///
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/// For example, returns 40 for i36 and 80 for x86_fp80.
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uint64_t getTypeStoreSizeInBits(Type *Ty) const {
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return 8 * getTypeStoreSize(Ty);
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}
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/// \brief Returns the offset in bytes between successive objects of the
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/// specified type, including alignment padding.
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///
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/// This is the amount that alloca reserves for this type. For example,
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/// returns 12 or 16 for x86_fp80, depending on alignment.
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uint64_t getTypeAllocSize(Type *Ty) const {
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// Round up to the next alignment boundary.
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return RoundUpToAlignment(getTypeStoreSize(Ty), getABITypeAlignment(Ty));
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}
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/// \brief Returns the offset in bits between successive objects of the
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/// specified type, including alignment padding; always a multiple of 8.
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///
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/// This is the amount that alloca reserves for this type. For example,
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/// returns 96 or 128 for x86_fp80, depending on alignment.
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uint64_t getTypeAllocSizeInBits(Type *Ty) const {
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return 8 * getTypeAllocSize(Ty);
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}
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/// \brief Returns the minimum ABI-required alignment for the specified type.
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unsigned getABITypeAlignment(Type *Ty) const;
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/// \brief Returns the minimum ABI-required alignment for an integer type of
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/// the specified bitwidth.
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unsigned getABIIntegerTypeAlignment(unsigned BitWidth) const;
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/// \brief Returns the preferred stack/global alignment for the specified
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/// type.
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///
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/// This is always at least as good as the ABI alignment.
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unsigned getPrefTypeAlignment(Type *Ty) const;
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/// \brief Returns the preferred alignment for the specified type, returned as
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/// log2 of the value (a shift amount).
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unsigned getPreferredTypeAlignmentShift(Type *Ty) const;
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/// \brief Returns an integer type with size at least as big as that of a
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/// pointer in the given address space.
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IntegerType *getIntPtrType(LLVMContext &C, unsigned AddressSpace = 0) const;
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/// \brief Returns an integer (vector of integer) type with size at least as
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/// big as that of a pointer of the given pointer (vector of pointer) type.
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Type *getIntPtrType(Type *) const;
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/// \brief Returns the smallest integer type with size at least as big as
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/// Width bits.
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Type *getSmallestLegalIntType(LLVMContext &C, unsigned Width = 0) const;
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/// \brief Returns the largest legal integer type, or null if none are set.
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Type *getLargestLegalIntType(LLVMContext &C) const {
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unsigned LargestSize = getLargestLegalIntTypeSize();
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return (LargestSize == 0) ? nullptr : Type::getIntNTy(C, LargestSize);
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}
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/// \brief Returns the size of largest legal integer type size, or 0 if none
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/// are set.
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unsigned getLargestLegalIntTypeSize() const;
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/// \brief Returns the offset from the beginning of the type for the specified
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/// indices.
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///
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/// This is used to implement getelementptr.
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uint64_t getIndexedOffset(Type *Ty, ArrayRef<Value *> Indices) const;
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/// \brief Returns a StructLayout object, indicating the alignment of the
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/// struct, its size, and the offsets of its fields.
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///
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/// Note that this information is lazily cached.
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const StructLayout *getStructLayout(StructType *Ty) const;
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/// \brief Returns the preferred alignment of the specified global.
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///
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/// This includes an explicitly requested alignment (if the global has one).
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unsigned getPreferredAlignment(const GlobalVariable *GV) const;
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/// \brief Returns the preferred alignment of the specified global, returned
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/// in log form.
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///
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/// This includes an explicitly requested alignment (if the global has one).
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unsigned getPreferredAlignmentLog(const GlobalVariable *GV) const;
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};
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inline DataLayout *unwrap(LLVMTargetDataRef P) {
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return reinterpret_cast<DataLayout *>(P);
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}
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inline LLVMTargetDataRef wrap(const DataLayout *P) {
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return reinterpret_cast<LLVMTargetDataRef>(const_cast<DataLayout *>(P));
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}
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class DataLayoutPass : public ImmutablePass {
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DataLayout DL;
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public:
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/// This has to exist, because this is a pass, but it should never be used.
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DataLayoutPass();
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~DataLayoutPass();
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const DataLayout &getDataLayout() const { return DL; }
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static char ID; // Pass identification, replacement for typeid
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bool doFinalization(Module &M) override;
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bool doInitialization(Module &M) override;
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};
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/// Used to lazily calculate structure layout information for a target machine,
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/// based on the DataLayout structure.
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class StructLayout {
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uint64_t StructSize;
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unsigned StructAlignment;
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unsigned NumElements;
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uint64_t MemberOffsets[1]; // variable sized array!
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public:
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uint64_t getSizeInBytes() const { return StructSize; }
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uint64_t getSizeInBits() const { return 8 * StructSize; }
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unsigned getAlignment() const { return StructAlignment; }
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/// \brief Given a valid byte offset into the structure, returns the structure
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/// index that contains it.
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unsigned getElementContainingOffset(uint64_t Offset) const;
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uint64_t getElementOffset(unsigned Idx) const {
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assert(Idx < NumElements && "Invalid element idx!");
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return MemberOffsets[Idx];
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}
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uint64_t getElementOffsetInBits(unsigned Idx) const {
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return getElementOffset(Idx) * 8;
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}
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private:
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friend class DataLayout; // Only DataLayout can create this class
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StructLayout(StructType *ST, const DataLayout &DL);
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};
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// The implementation of this method is provided inline as it is particularly
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// well suited to constant folding when called on a specific Type subclass.
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inline uint64_t DataLayout::getTypeSizeInBits(Type *Ty) const {
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assert(Ty->isSized() && "Cannot getTypeInfo() on a type that is unsized!");
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switch (Ty->getTypeID()) {
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case Type::LabelTyID:
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return getPointerSizeInBits(0);
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case Type::PointerTyID:
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return getPointerSizeInBits(Ty->getPointerAddressSpace());
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case Type::ArrayTyID: {
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ArrayType *ATy = cast<ArrayType>(Ty);
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return ATy->getNumElements() *
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getTypeAllocSizeInBits(ATy->getElementType());
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}
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case Type::StructTyID:
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// Get the layout annotation... which is lazily created on demand.
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return getStructLayout(cast<StructType>(Ty))->getSizeInBits();
|
|
case Type::IntegerTyID:
|
|
return Ty->getIntegerBitWidth();
|
|
case Type::HalfTyID:
|
|
return 16;
|
|
case Type::FloatTyID:
|
|
return 32;
|
|
case Type::DoubleTyID:
|
|
case Type::X86_MMXTyID:
|
|
return 64;
|
|
case Type::PPC_FP128TyID:
|
|
case Type::FP128TyID:
|
|
return 128;
|
|
// In memory objects this is always aligned to a higher boundary, but
|
|
// only 80 bits contain information.
|
|
case Type::X86_FP80TyID:
|
|
return 80;
|
|
case Type::VectorTyID: {
|
|
VectorType *VTy = cast<VectorType>(Ty);
|
|
return VTy->getNumElements() * getTypeSizeInBits(VTy->getElementType());
|
|
}
|
|
default:
|
|
llvm_unreachable("DataLayout::getTypeSizeInBits(): Unsupported type");
|
|
}
|
|
}
|
|
|
|
} // End llvm namespace
|
|
|
|
#endif
|