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7a5199df98
This pass is meant to be immutable, however it holds mutable state to cache StructLayouts. This method will allow the pass manager to clear the mutable state between runs. Note that unfortunately it is still necessary to have the destructor, even though it does the same thing as doFinalization. This is because most TargetMachines embed a DataLayout on which doFinalization isn't run as its never added to the pass manager. I also didn't think it was necessary to complication things with a deInit method for which doFinalization and ~DataLayout both call as there's only one field of mutable state. If we had more fields to finalize i'd have added this. llvm-svn: 176877
429 lines
16 KiB
C++
429 lines
16 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/Pass.h"
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#include "llvm/Support/DataTypes.h"
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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 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, ///< An invalid alignment
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INTEGER_ALIGN = 'i', ///< Integer type alignment
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VECTOR_ALIGN = 'v', ///< Vector type alignment
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FLOAT_ALIGN = 'f', ///< Floating point type alignment
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AGGREGATE_ALIGN = 'a', ///< Aggregate alignment
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STACK_ALIGN = 's' ///< Stack objects alignment
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};
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/// 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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unsigned AlignType : 8; ///< Alignment type (AlignTypeEnum)
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unsigned TypeBitWidth : 24; ///< Type bit width
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unsigned ABIAlign : 16; ///< ABI alignment for this type/bitw
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unsigned PrefAlign : 16; ///< Pref. alignment for this type/bitw
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/// Initializer
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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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/// Equality predicate
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bool operator==(const LayoutAlignElem &rhs) const;
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};
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/// 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; ///< ABI alignment for this type/bitw
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unsigned PrefAlign; ///< Pref. alignment for this type/bitw
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uint32_t TypeBitWidth; ///< Type bit width
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uint32_t AddressSpace; ///< Address space for the pointer type
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/// Initializer
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static PointerAlignElem get(uint32_t addr_space, unsigned abi_align,
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unsigned pref_align, uint32_t bit_width);
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/// Equality predicate
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bool operator==(const PointerAlignElem &rhs) const;
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};
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/// DataLayout - This class holds a parsed version of the target data layout
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/// string in a module and provides methods for querying it. The target data
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/// layout string is specified *by the target* - a frontend generating LLVM IR
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/// is required to generate the right target data for the target being codegen'd
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/// to. If some measure of portability is desired, an empty string may be
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/// specified in the module.
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class DataLayout : public ImmutablePass {
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private:
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bool LittleEndian; ///< Defaults to false
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unsigned StackNaturalAlign; ///< Stack natural alignment
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SmallVector<unsigned char, 8> LegalIntWidths; ///< Legal Integers.
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/// Alignments - Where the primitive type alignment data is stored.
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///
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/// @sa init().
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/// @note Could support multiple size pointer alignments, e.g., 32-bit
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/// pointers vs. 64-bit pointers by extending LayoutAlignment, but for now,
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/// we don't.
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SmallVector<LayoutAlignElem, 16> Alignments;
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DenseMap<unsigned, PointerAlignElem> Pointers;
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/// InvalidAlignmentElem - This member is a signal that a requested alignment
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/// type and bit width were not found in the SmallVector.
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static const LayoutAlignElem InvalidAlignmentElem;
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/// InvalidPointerElem - This member is a signal that a requested pointer
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/// type and bit width were 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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//! Set/initialize target alignments
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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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//! Set/initialize pointer alignments
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void setPointerAlignment(uint32_t addr_space, unsigned abi_align,
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unsigned pref_align, uint32_t bit_width);
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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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/// 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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/// Valid pointer predicate.
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///
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/// Predicate that tests a PointerAlignElem reference returned by get() against
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/// 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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public:
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/// Default ctor.
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///
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/// @note This has to exist, because this is a pass, but it should never be
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/// used.
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DataLayout();
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/// Constructs a DataLayout from a specification string. See init().
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explicit DataLayout(StringRef LayoutDescription)
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: ImmutablePass(ID) {
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init(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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DataLayout(const DataLayout &TD) :
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ImmutablePass(ID),
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LittleEndian(TD.isLittleEndian()),
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StackNaturalAlign(TD.StackNaturalAlign),
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LegalIntWidths(TD.LegalIntWidths),
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Alignments(TD.Alignments),
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Pointers(TD.Pointers),
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LayoutMap(0)
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{ }
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~DataLayout(); // Not virtual, do not subclass this class
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/// DataLayout is an immutable pass, but holds state. This allows the pass
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/// manager to clear its mutable state.
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bool doFinalization(Module &M);
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/// Parse a data layout string (with fallback to default values). Ensure that
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/// the data layout pass is registered.
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void init(StringRef LayoutDescription);
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/// Layout endianness...
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bool isLittleEndian() const { return LittleEndian; }
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bool isBigEndian() const { return !LittleEndian; }
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/// getStringRepresentation - Return the string representation of the
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/// DataLayout. This representation is in the same format accepted by the
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/// string constructor above.
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std::string getStringRepresentation() const;
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/// isLegalInteger - This function returns true if the specified type is
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/// known to be a native integer type supported by the CPU. For example,
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/// i64 is not native on most 32-bit CPUs and i37 is not native on any known
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/// 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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///
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bool isLegalInteger(unsigned Width) const {
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for (unsigned i = 0, e = (unsigned)LegalIntWidths.size(); i != e; ++i)
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if (LegalIntWidths[i] == 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 {
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return !isLegalInteger(Width);
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}
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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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/// fitsInLegalInteger - This function returns true if the specified type fits
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/// in a native integer type supported by the CPU. For example, if the CPU
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/// only supports i32 as a native integer type, then i27 fits in a legal
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// integer type but i45 does not.
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bool fitsInLegalInteger(unsigned Width) const {
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for (unsigned i = 0, e = (unsigned)LegalIntWidths.size(); i != e; ++i)
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if (Width <= LegalIntWidths[i])
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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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DenseMap<unsigned, PointerAlignElem>::const_iterator val = Pointers.find(AS);
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if (val == Pointers.end()) {
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val = Pointers.find(0);
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}
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return val->second.ABIAlign;
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}
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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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DenseMap<unsigned, PointerAlignElem>::const_iterator val = Pointers.find(AS);
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if (val == Pointers.end()) {
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val = Pointers.find(0);
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}
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return val->second.PrefAlign;
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}
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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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DenseMap<unsigned, PointerAlignElem>::const_iterator val = Pointers.find(AS);
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if (val == Pointers.end()) {
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val = Pointers.find(0);
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}
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return val->second.TypeBitWidth;
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}
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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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/// 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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/// getTypeSizeInBits - Return the number of bits necessary to hold the
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/// specified type. For example, returns 36 for i36 and 80 for x86_fp80.
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/// The type passed must have a size (Type::isSized() must return true).
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uint64_t getTypeSizeInBits(Type *Ty) const;
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/// getTypeStoreSize - Return the maximum number of bytes that may be
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/// overwritten by storing the specified type. For example, returns 5
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/// 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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/// getTypeStoreSizeInBits - Return the maximum number of bits that may be
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/// overwritten by storing the specified type; always a multiple of 8. For
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/// 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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/// getTypeAllocSize - Return the offset in bytes between successive objects
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/// of the specified type, including alignment padding. This is the amount
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/// that alloca reserves for this type. For example, returns 12 or 16 for
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/// 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 RoundUpAlignment(getTypeStoreSize(Ty), getABITypeAlignment(Ty));
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}
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/// getTypeAllocSizeInBits - Return the offset in bits between successive
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/// objects of the specified type, including alignment padding; always a
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/// multiple of 8. This is the amount that alloca reserves for this type.
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/// For example, 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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/// getABITypeAlignment - Return the minimum ABI-required alignment for the
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/// specified type.
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unsigned getABITypeAlignment(Type *Ty) const;
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/// getABIIntegerTypeAlignment - Return the minimum ABI-required alignment for
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/// an integer type of the specified bitwidth.
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unsigned getABIIntegerTypeAlignment(unsigned BitWidth) const;
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/// getCallFrameTypeAlignment - Return the minimum ABI-required alignment
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/// for the specified type when it is part of a call frame.
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unsigned getCallFrameTypeAlignment(Type *Ty) const;
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/// getPrefTypeAlignment - Return the preferred stack/global alignment for
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/// the specified type. This is always at least as good as the ABI alignment.
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unsigned getPrefTypeAlignment(Type *Ty) const;
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/// getPreferredTypeAlignmentShift - Return the preferred alignment for the
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/// specified type, returned as log2 of the value (a shift amount).
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unsigned getPreferredTypeAlignmentShift(Type *Ty) const;
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/// getIntPtrType - Return an integer type with size at least as big as that
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/// of a pointer in the given address space.
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IntegerType *getIntPtrType(LLVMContext &C, unsigned AddressSpace = 0) const;
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/// getIntPtrType - Return an integer (vector of integer) type with size at
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/// least as big as that of a pointer of the given pointer (vector of pointer)
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/// type.
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Type *getIntPtrType(Type *) const;
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/// getIndexedOffset - return the offset from the beginning of the type for
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/// the specified indices. This is used to implement getelementptr.
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uint64_t getIndexedOffset(Type *Ty, ArrayRef<Value *> Indices) const;
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/// getStructLayout - Return a StructLayout object, indicating the alignment
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/// of the struct, its size, and the offsets of its fields. Note that this
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/// information is lazily cached.
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const StructLayout *getStructLayout(StructType *Ty) const;
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/// getPreferredAlignment - Return the preferred alignment of the specified
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/// global. This includes an explicitly requested alignment (if the global
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/// has one).
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unsigned getPreferredAlignment(const GlobalVariable *GV) const;
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/// getPreferredAlignmentLog - Return the preferred alignment of the
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/// specified global, returned in log form. This includes an explicitly
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/// requested alignment (if the global has one).
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unsigned getPreferredAlignmentLog(const GlobalVariable *GV) const;
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/// RoundUpAlignment - Round the specified value up to the next alignment
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/// boundary specified by Alignment. For example, 7 rounded up to an
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/// alignment boundary of 4 is 8. 8 rounded up to the alignment boundary of 4
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/// is 8 because it is already aligned.
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template <typename UIntTy>
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static UIntTy RoundUpAlignment(UIntTy Val, unsigned Alignment) {
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assert((Alignment & (Alignment-1)) == 0 && "Alignment must be power of 2!");
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return (Val + (Alignment-1)) & ~UIntTy(Alignment-1);
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}
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static char ID; // Pass identification, replacement for typeid
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};
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/// StructLayout - used to lazily calculate structure layout information for a
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/// target machine, based on the DataLayout structure.
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///
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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 {
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return StructSize;
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}
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uint64_t getSizeInBits() const {
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return 8*StructSize;
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}
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unsigned getAlignment() const {
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return StructAlignment;
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}
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/// getElementContainingOffset - Given a valid byte offset into the structure,
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/// return the structure index that contains it.
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///
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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 &TD);
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};
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} // End llvm namespace
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#endif
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