1202884fd9b575396f7ca220755cc4e3dac9b5a97Chris Lattner//===-- llvm/Use.h - Definition of the Use class ----------------*- C++ -*-===// 29769ab22265b313171d201b5928688524a01bd87Misha Brukman// 36fbcc26f1460eaee4e0eb8b426fc1ff0c7af11beJohn Criswell// The LLVM Compiler Infrastructure 46fbcc26f1460eaee4e0eb8b426fc1ff0c7af11beJohn Criswell// 57ed47a13356daed2a34cd2209a31f92552e3bdd8Chris Lattner// This file is distributed under the University of Illinois Open Source 67ed47a13356daed2a34cd2209a31f92552e3bdd8Chris Lattner// License. See LICENSE.TXT for details. 79769ab22265b313171d201b5928688524a01bd87Misha Brukman// 86fbcc26f1460eaee4e0eb8b426fc1ff0c7af11beJohn Criswell//===----------------------------------------------------------------------===// 936b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines/// \file 1036b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines/// 1136b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines/// This defines the Use class. The Use class represents the operand of an 1236b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines/// instruction or some other User instance which refers to a Value. The Use 1336b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines/// class keeps the "use list" of the referenced value up to date. 1436b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines/// 1536b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines/// Pointer tagging is used to efficiently find the User corresponding to a Use 1636b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines/// without having to store a User pointer in every Use. A User is preceded in 1736b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines/// memory by all the Uses corresponding to its operands, and the low bits of 1836b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines/// one of the fields (Prev) of the Use class are used to encode offsets to be 1936b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines/// able to find that User given a pointer to any Use. For details, see: 2036b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines/// 2136b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines/// http://www.llvm.org/docs/ProgrammersManual.html#UserLayout 2236b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines/// 23202884fd9b575396f7ca220755cc4e3dac9b5a97Chris Lattner//===----------------------------------------------------------------------===// 24202884fd9b575396f7ca220755cc4e3dac9b5a97Chris Lattner 25674be02d525d4e24bc6943ed9274958c580bcfbcJakub Staszak#ifndef LLVM_IR_USE_H 26674be02d525d4e24bc6943ed9274958c580bcfbcJakub Staszak#define LLVM_IR_USE_H 27202884fd9b575396f7ca220755cc4e3dac9b5a97Chris Lattner 2836b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines#include "llvm-c/Core.h" 29fd095b6389ec7c794e094f2a5dc8851bdc108999Gabor Greif#include "llvm/ADT/PointerIntPair.h" 3040be1e85665d10f5444186f0e7106e368dd735b8Filip Pizlo#include "llvm/Support/CBindingWrapping.h" 31daca73f9bec4ce02045aa5a631a60221c33262cfCraig Topper#include "llvm/Support/Compiler.h" 32ae479aa13ed344876680f7d4dc08e3cf4b512da9Nick Lewycky#include <cstddef> 33f0891be8bdbeeadb39da5575273b6645755fa383Gabor Greif#include <iterator> 34d0fde30ce850b78371fd1386338350591f9ff494Brian Gaeke 35d0fde30ce850b78371fd1386338350591f9ff494Brian Gaekenamespace llvm { 36d0fde30ce850b78371fd1386338350591f9ff494Brian Gaeke 37202884fd9b575396f7ca220755cc4e3dac9b5a97Chris Lattnerclass Value; 38202884fd9b575396f7ca220755cc4e3dac9b5a97Chris Lattnerclass User; 39e30173ac3396510bd0bb26a66fd615ff9083436dChris Lattnerclass Use; 4036b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hinestemplate <typename> struct simplify_type; 41202884fd9b575396f7ca220755cc4e3dac9b5a97Chris Lattner 42b7a00daa1165576dd2bb9d17970c249d536f4a82Chris Lattner// Use** is only 4-byte aligned. 4336b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hinestemplate <> class PointerLikeTypeTraits<Use **> { 44b7a00daa1165576dd2bb9d17970c249d536f4a82Chris Lattnerpublic: 4536b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines static inline void *getAsVoidPointer(Use **P) { return P; } 46b7a00daa1165576dd2bb9d17970c249d536f4a82Chris Lattner static inline Use **getFromVoidPointer(void *P) { 4736b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines return static_cast<Use **>(P); 48b7a00daa1165576dd2bb9d17970c249d536f4a82Chris Lattner } 49b7a00daa1165576dd2bb9d17970c249d536f4a82Chris Lattner enum { NumLowBitsAvailable = 2 }; 50b7a00daa1165576dd2bb9d17970c249d536f4a82Chris Lattner}; 51b7a00daa1165576dd2bb9d17970c249d536f4a82Chris Lattner 5236b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines/// \brief A Use represents the edge between a Value definition and its users. 5336b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines/// 5436b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines/// This is notionally a two-dimensional linked list. It supports traversing 5536b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines/// all of the uses for a particular value definition. It also supports jumping 5636b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines/// directly to the used value when we arrive from the User's operands, and 5736b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines/// jumping directly to the User when we arrive from the Value's uses. 5836b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines/// 5936b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines/// The pointer to the used Value is explicit, and the pointer to the User is 6036b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines/// implicit. The implicit pointer is found via a waymarking algorithm 6136b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines/// described in the programmer's manual: 6236b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines/// 63dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines/// http://www.llvm.org/docs/ProgrammersManual.html#the-waymarking-algorithm 6436b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines/// 6536b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines/// This is essentially the single most memory intensive object in LLVM because 6636b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines/// of the number of uses in the system. At the same time, the constant time 6736b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines/// operations it allows are essential to many optimizations having reasonable 6836b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines/// time complexity. 69202884fd9b575396f7ca220755cc4e3dac9b5a97Chris Lattnerclass Use { 706f4266506bca785828bacda55bd5db9172f990c6Gabor Greifpublic: 7136b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines /// \brief Provide a fast substitute to std::swap<Use> 7294fb68ba217975d2d99ae86d15993402158ac655Gabor Greif /// that also works with less standard-compliant compilers 7394fb68ba217975d2d99ae86d15993402158ac655Gabor Greif void swap(Use &RHS); 74b8d5b1211f982d65546d855130d99c42780a76a0Chris Lattner 75691c05bb29d3e2ec9c2ed6b1c082ce5d484b75daJay Foad // A type for the word following an array of hung-off Uses in memory, which is 76691c05bb29d3e2ec9c2ed6b1c082ce5d484b75daJay Foad // a pointer back to their User with the bottom bit set. 7736b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines typedef PointerIntPair<User *, 1, unsigned> UserRef; 78691c05bb29d3e2ec9c2ed6b1c082ce5d484b75daJay Foad 79efe65369a74871c3140a540a6c95ce5d1f080954Gabor Greifprivate: 80f630e49efc7bf3f1716b6daab3c2cc11a908754aCraig Topper Use(const Use &U) LLVM_DELETED_FUNCTION; 81efe65369a74871c3140a540a6c95ce5d1f080954Gabor Greif 8294fb68ba217975d2d99ae86d15993402158ac655Gabor Greif /// Destructor - Only for zap() 831ed26acc58a13f125bc9e1d5e5aa22fd479654ffJay Foad ~Use() { 8436b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines if (Val) 8536b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines removeFromList(); 8659dc98de2f79c027eb6860443daee260710b1405Gabor Greif } 87202884fd9b575396f7ca220755cc4e3dac9b5a97Chris Lattner 8836b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines enum PrevPtrTag { zeroDigitTag, oneDigitTag, stopTag, fullStopTag }; 896f4266506bca785828bacda55bd5db9172f990c6Gabor Greif 901ed26acc58a13f125bc9e1d5e5aa22fd479654ffJay Foad /// Constructor 91dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines Use(PrevPtrTag tag) : Val(nullptr) { Prev.setInt(tag); } 921ed26acc58a13f125bc9e1d5e5aa22fd479654ffJay Foad 93efe65369a74871c3140a540a6c95ce5d1f080954Gabor Greifpublic: 9436b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines operator Value *() const { return Val; } 956f4266506bca785828bacda55bd5db9172f990c6Gabor Greif Value *get() const { return Val; } 9636b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines 9736b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines /// \brief Returns the User that contains this Use. 9836b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines /// 9936b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines /// For an instruction operand, for example, this will return the 10036b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines /// instruction. 101efe65369a74871c3140a540a6c95ce5d1f080954Gabor Greif User *getUser() const; 102202884fd9b575396f7ca220755cc4e3dac9b5a97Chris Lattner 103202884fd9b575396f7ca220755cc4e3dac9b5a97Chris Lattner inline void set(Value *Val); 104202884fd9b575396f7ca220755cc4e3dac9b5a97Chris Lattner 105202884fd9b575396f7ca220755cc4e3dac9b5a97Chris Lattner Value *operator=(Value *RHS) { 106202884fd9b575396f7ca220755cc4e3dac9b5a97Chris Lattner set(RHS); 107202884fd9b575396f7ca220755cc4e3dac9b5a97Chris Lattner return RHS; 108202884fd9b575396f7ca220755cc4e3dac9b5a97Chris Lattner } 109202884fd9b575396f7ca220755cc4e3dac9b5a97Chris Lattner const Use &operator=(const Use &RHS) { 1106f4266506bca785828bacda55bd5db9172f990c6Gabor Greif set(RHS.Val); 111202884fd9b575396f7ca220755cc4e3dac9b5a97Chris Lattner return *this; 112202884fd9b575396f7ca220755cc4e3dac9b5a97Chris Lattner } 113202884fd9b575396f7ca220755cc4e3dac9b5a97Chris Lattner 11436b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines Value *operator->() { return Val; } 1156f4266506bca785828bacda55bd5db9172f990c6Gabor Greif const Value *operator->() const { return Val; } 11602accaeb172fbe179fe20eafa6172606d0c9eae1Chris Lattner 1176f4266506bca785828bacda55bd5db9172f990c6Gabor Greif Use *getNext() const { return Next; } 118a870039277d26d3d8f3ff774345db90096b544adChris Lattner 11936b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines /// \brief Return the operand # of this use in its User. 12036b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines unsigned getOperandNo() const; 12136b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines 12236b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines /// \brief Initializes the waymarking tags on an array of Uses. 12336b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines /// 12436b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines /// This sets up the array of Uses such that getUser() can find the User from 12536b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines /// any of those Uses. 12695c3e48f9557adb6064d580684bb14cacec2f826Jay Foad static Use *initTags(Use *Start, Use *Stop); 12795c3e48f9557adb6064d580684bb14cacec2f826Jay Foad 12836b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines /// \brief Destroys Use operands when the number of operands of 129a870039277d26d3d8f3ff774345db90096b544adChris Lattner /// a User changes. 130a870039277d26d3d8f3ff774345db90096b544adChris Lattner static void zap(Use *Start, const Use *Stop, bool del = false); 131a870039277d26d3d8f3ff774345db90096b544adChris Lattner 13202accaeb172fbe179fe20eafa6172606d0c9eae1Chris Lattnerprivate: 13336b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines const Use *getImpliedUser() const; 13436b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines 1356f4266506bca785828bacda55bd5db9172f990c6Gabor Greif Value *Val; 136fd095b6389ec7c794e094f2a5dc8851bdc108999Gabor Greif Use *Next; 13736b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines PointerIntPair<Use **, 2, PrevPtrTag> Prev; 138202884fd9b575396f7ca220755cc4e3dac9b5a97Chris Lattner 13936b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines void setPrev(Use **NewPrev) { Prev.setPointer(NewPrev); } 140a26619748932b146a09773d51465d7b7dcdb7dd2Chris Lattner void addToList(Use **List) { 141a26619748932b146a09773d51465d7b7dcdb7dd2Chris Lattner Next = *List; 14236b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines if (Next) 14336b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines Next->setPrev(&Next); 144efe65369a74871c3140a540a6c95ce5d1f080954Gabor Greif setPrev(List); 145a26619748932b146a09773d51465d7b7dcdb7dd2Chris Lattner *List = this; 146a26619748932b146a09773d51465d7b7dcdb7dd2Chris Lattner } 147a26619748932b146a09773d51465d7b7dcdb7dd2Chris Lattner void removeFromList() { 148fd095b6389ec7c794e094f2a5dc8851bdc108999Gabor Greif Use **StrippedPrev = Prev.getPointer(); 149efe65369a74871c3140a540a6c95ce5d1f080954Gabor Greif *StrippedPrev = Next; 15036b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines if (Next) 15136b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines Next->setPrev(StrippedPrev); 152a26619748932b146a09773d51465d7b7dcdb7dd2Chris Lattner } 153202884fd9b575396f7ca220755cc4e3dac9b5a97Chris Lattner 154a26619748932b146a09773d51465d7b7dcdb7dd2Chris Lattner friend class Value; 155a26619748932b146a09773d51465d7b7dcdb7dd2Chris Lattner}; 156202884fd9b575396f7ca220755cc4e3dac9b5a97Chris Lattner 15736b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines/// \brief Allow clients to treat uses just like values when using 15836b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines/// casting operators. 15936b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hinestemplate <> struct simplify_type<Use> { 16036b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines typedef Value *SimpleType; 16136b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines static SimpleType getSimplifiedValue(Use &Val) { return Val.get(); } 162202884fd9b575396f7ca220755cc4e3dac9b5a97Chris Lattner}; 16336b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hinestemplate <> struct simplify_type<const Use> { 16436b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines typedef /*const*/ Value *SimpleType; 16536b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines static SimpleType getSimplifiedValue(const Use &Val) { return Val.get(); } 166202884fd9b575396f7ca220755cc4e3dac9b5a97Chris Lattner}; 167202884fd9b575396f7ca220755cc4e3dac9b5a97Chris Lattner 16840be1e85665d10f5444186f0e7106e368dd735b8Filip Pizlo// Create wrappers for C Binding types (see CBindingWrapping.h). 16940be1e85665d10f5444186f0e7106e368dd735b8Filip PizloDEFINE_SIMPLE_CONVERSION_FUNCTIONS(Use, LLVMUseRef) 17040be1e85665d10f5444186f0e7106e368dd735b8Filip Pizlo 17136b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines} 172d0fde30ce850b78371fd1386338350591f9ff494Brian Gaeke 173202884fd9b575396f7ca220755cc4e3dac9b5a97Chris Lattner#endif 174