116c29b5f285f375be53dabaa73e3e91107485fe4Anton Korobeynikov//===-- llvm/Target/TargetFrameLowering.h ---------------------------*- C++ -*-===// 234695381d626485a560594f162701088079589dfMisha 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. 734695381d626485a560594f162701088079589dfMisha Brukman// 86fbcc26f1460eaee4e0eb8b426fc1ff0c7af11beJohn Criswell//===----------------------------------------------------------------------===// 9035dfbe7f2d109008d2d62d9f2a67efb477a7ab6Chris Lattner// 10fd529d2e4aed9a455d539962248fda8583d6ba8eChris Lattner// Interface to describe the layout of a stack frame on the target machine. 11035dfbe7f2d109008d2d62d9f2a67efb477a7ab6Chris Lattner// 12035dfbe7f2d109008d2d62d9f2a67efb477a7ab6Chris Lattner//===----------------------------------------------------------------------===// 137cffcaaa48656fa6f90b041cc5f056304addef32Vikram S. Adve 1416c29b5f285f375be53dabaa73e3e91107485fe4Anton Korobeynikov#ifndef LLVM_TARGET_TARGETFRAMELOWERING_H 1516c29b5f285f375be53dabaa73e3e91107485fe4Anton Korobeynikov#define LLVM_TARGET_TARGETFRAMELOWERING_H 167cffcaaa48656fa6f90b041cc5f056304addef32Vikram S. Adve 17cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov#include "llvm/CodeGen/MachineBasicBlock.h" 1809431e187f9abd45af08461df728204ee9731fd7Chris Lattner#include <utility> 19d9e3385ced2dc887e2fe8e1c071bd2611e4d3edeAnton Korobeynikov#include <vector> 2009431e187f9abd45af08461df728204ee9731fd7Chris Lattner 21d0fde30ce850b78371fd1386338350591f9ff494Brian Gaekenamespace llvm { 22cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar class BitVector; 23cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov class CalleeSavedInfo; 2433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov class MachineFunction; 2594c5ae08750f314bc3cf1bf882b686244a3927d9Anton Korobeynikov class RegScavenger; 26d0fde30ce850b78371fd1386338350591f9ff494Brian Gaeke 27c07c0df634d31849ac659234e4718b57ddacb882Chris Lattner/// Information about stack frame layout on the target. It holds the direction 28c07c0df634d31849ac659234e4718b57ddacb882Chris Lattner/// of stack growth, the known stack alignment on entry to each function, and 29c07c0df634d31849ac659234e4718b57ddacb882Chris Lattner/// the offset to the locals area. 30c07c0df634d31849ac659234e4718b57ddacb882Chris Lattner/// 31c07c0df634d31849ac659234e4718b57ddacb882Chris Lattner/// The offset to the local area is the offset from the stack pointer on 32c07c0df634d31849ac659234e4718b57ddacb882Chris Lattner/// function entry to the first location where function data (local variables, 33c07c0df634d31849ac659234e4718b57ddacb882Chris Lattner/// spill locations) can be stored. 3416c29b5f285f375be53dabaa73e3e91107485fe4Anton Korobeynikovclass TargetFrameLowering { 351fca5ff62bb2ecb5bfc8974f4dbfc56e9d3ca721Chris Lattnerpublic: 36fd529d2e4aed9a455d539962248fda8583d6ba8eChris Lattner enum StackDirection { 37fd529d2e4aed9a455d539962248fda8583d6ba8eChris Lattner StackGrowsUp, // Adding to the stack increases the stack address 38fd529d2e4aed9a455d539962248fda8583d6ba8eChris Lattner StackGrowsDown // Adding to the stack decreases the stack address 39fd529d2e4aed9a455d539962248fda8583d6ba8eChris Lattner }; 408ff95de83cbe85d939535d2f4fb5f9b2b721081aTilmann Scheller 418ff95de83cbe85d939535d2f4fb5f9b2b721081aTilmann Scheller // Maps a callee saved register to a stack slot with a fixed offset. 428ff95de83cbe85d939535d2f4fb5f9b2b721081aTilmann Scheller struct SpillSlot { 438ff95de83cbe85d939535d2f4fb5f9b2b721081aTilmann Scheller unsigned Reg; 448ff95de83cbe85d939535d2f4fb5f9b2b721081aTilmann Scheller int Offset; // Offset relative to stack pointer on function entry. 458ff95de83cbe85d939535d2f4fb5f9b2b721081aTilmann Scheller }; 46fd529d2e4aed9a455d539962248fda8583d6ba8eChris Lattnerprivate: 47fd529d2e4aed9a455d539962248fda8583d6ba8eChris Lattner StackDirection StackDir; 48fd529d2e4aed9a455d539962248fda8583d6ba8eChris Lattner unsigned StackAlignment; 490035f9c3b9982eeef098b608fceb7572df969b3eBob Wilson unsigned TransientStackAlignment; 50fd529d2e4aed9a455d539962248fda8583d6ba8eChris Lattner int LocalAreaOffset; 5169261a644298bff1497d46c8cd38d688670f307bManman Ren bool StackRealignable; 527cffcaaa48656fa6f90b041cc5f056304addef32Vikram S. Advepublic: 5316c29b5f285f375be53dabaa73e3e91107485fe4Anton Korobeynikov TargetFrameLowering(StackDirection D, unsigned StackAl, int LAO, 5469261a644298bff1497d46c8cd38d688670f307bManman Ren unsigned TransAl = 1, bool StackReal = true) 550035f9c3b9982eeef098b608fceb7572df969b3eBob Wilson : StackDir(D), StackAlignment(StackAl), TransientStackAlignment(TransAl), 5669261a644298bff1497d46c8cd38d688670f307bManman Ren LocalAreaOffset(LAO), StackRealignable(StackReal) {} 57fd529d2e4aed9a455d539962248fda8583d6ba8eChris Lattner 5816c29b5f285f375be53dabaa73e3e91107485fe4Anton Korobeynikov virtual ~TargetFrameLowering(); 59a1aad3b0eda2a516f663cb5f9f8c4c9bbb6ef224Reid Spencer 60fd529d2e4aed9a455d539962248fda8583d6ba8eChris Lattner // These methods return information that describes the abstract stack layout 61fd529d2e4aed9a455d539962248fda8583d6ba8eChris Lattner // of the target machine. 62fd529d2e4aed9a455d539962248fda8583d6ba8eChris Lattner 63fd529d2e4aed9a455d539962248fda8583d6ba8eChris Lattner /// getStackGrowthDirection - Return the direction the stack grows 64fd529d2e4aed9a455d539962248fda8583d6ba8eChris Lattner /// 65fd529d2e4aed9a455d539962248fda8583d6ba8eChris Lattner StackDirection getStackGrowthDirection() const { return StackDir; } 66fd529d2e4aed9a455d539962248fda8583d6ba8eChris Lattner 670035f9c3b9982eeef098b608fceb7572df969b3eBob Wilson /// getStackAlignment - This method returns the number of bytes to which the 680035f9c3b9982eeef098b608fceb7572df969b3eBob Wilson /// stack pointer must be aligned on entry to a function. Typically, this 690035f9c3b9982eeef098b608fceb7572df969b3eBob Wilson /// is the largest alignment for any data object in the target. 70fd529d2e4aed9a455d539962248fda8583d6ba8eChris Lattner /// 71fd529d2e4aed9a455d539962248fda8583d6ba8eChris Lattner unsigned getStackAlignment() const { return StackAlignment; } 72fd529d2e4aed9a455d539962248fda8583d6ba8eChris Lattner 73cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar /// alignSPAdjust - This method aligns the stack adjustment to the correct 74cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar /// alignment. 75cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar /// 76cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar int alignSPAdjust(int SPAdj) const { 77cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar if (SPAdj < 0) { 78cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar SPAdj = -RoundUpToAlignment(-SPAdj, StackAlignment); 79cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar } else { 80cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar SPAdj = RoundUpToAlignment(SPAdj, StackAlignment); 81cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar } 82cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar return SPAdj; 83cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar } 84cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar 850035f9c3b9982eeef098b608fceb7572df969b3eBob Wilson /// getTransientStackAlignment - This method returns the number of bytes to 860035f9c3b9982eeef098b608fceb7572df969b3eBob Wilson /// which the stack pointer must be aligned at all times, even between 870035f9c3b9982eeef098b608fceb7572df969b3eBob Wilson /// calls. 880035f9c3b9982eeef098b608fceb7572df969b3eBob Wilson /// 890035f9c3b9982eeef098b608fceb7572df969b3eBob Wilson unsigned getTransientStackAlignment() const { 900035f9c3b9982eeef098b608fceb7572df969b3eBob Wilson return TransientStackAlignment; 910035f9c3b9982eeef098b608fceb7572df969b3eBob Wilson } 920035f9c3b9982eeef098b608fceb7572df969b3eBob Wilson 9369261a644298bff1497d46c8cd38d688670f307bManman Ren /// isStackRealignable - This method returns whether the stack can be 9469261a644298bff1497d46c8cd38d688670f307bManman Ren /// realigned. 9569261a644298bff1497d46c8cd38d688670f307bManman Ren bool isStackRealignable() const { 9669261a644298bff1497d46c8cd38d688670f307bManman Ren return StackRealignable; 9769261a644298bff1497d46c8cd38d688670f307bManman Ren } 9869261a644298bff1497d46c8cd38d688670f307bManman Ren 99cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar /// Return the skew that has to be applied to stack alignment under 100cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar /// certain conditions (e.g. stack was adjusted before function \p MF 101cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar /// was called). 102cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar virtual unsigned getStackAlignmentSkew(const MachineFunction &MF) const; 103cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar 104fd529d2e4aed9a455d539962248fda8583d6ba8eChris Lattner /// getOffsetOfLocalArea - This method returns the offset of the local area 105fd529d2e4aed9a455d539962248fda8583d6ba8eChris Lattner /// from the stack pointer on entrance to a function. 106fd529d2e4aed9a455d539962248fda8583d6ba8eChris Lattner /// 107fd529d2e4aed9a455d539962248fda8583d6ba8eChris Lattner int getOffsetOfLocalArea() const { return LocalAreaOffset; } 108fd529d2e4aed9a455d539962248fda8583d6ba8eChris Lattner 1097271ac2c0318043688ddc8686dd23777dca62c59Richard Sandiford /// isFPCloseToIncomingSP - Return true if the frame pointer is close to 1107271ac2c0318043688ddc8686dd23777dca62c59Richard Sandiford /// the incoming stack pointer, false if it is close to the post-prologue 1117271ac2c0318043688ddc8686dd23777dca62c59Richard Sandiford /// stack pointer. 1127271ac2c0318043688ddc8686dd23777dca62c59Richard Sandiford virtual bool isFPCloseToIncomingSP() const { return true; } 1137271ac2c0318043688ddc8686dd23777dca62c59Richard Sandiford 114c6a4f5e819217e1e12c458aed8e7b122e23a3a58Stephen Hines /// assignCalleeSavedSpillSlots - Allows target to override spill slot 115c6a4f5e819217e1e12c458aed8e7b122e23a3a58Stephen Hines /// assignment logic. If implemented, assignCalleeSavedSpillSlots() should 116c6a4f5e819217e1e12c458aed8e7b122e23a3a58Stephen Hines /// assign frame slots to all CSI entries and return true. If this method 117c6a4f5e819217e1e12c458aed8e7b122e23a3a58Stephen Hines /// returns false, spill slots will be assigned using generic implementation. 118c6a4f5e819217e1e12c458aed8e7b122e23a3a58Stephen Hines /// assignCalleeSavedSpillSlots() may add, delete or rearrange elements of 119c6a4f5e819217e1e12c458aed8e7b122e23a3a58Stephen Hines /// CSI. 120c6a4f5e819217e1e12c458aed8e7b122e23a3a58Stephen Hines virtual bool 121c6a4f5e819217e1e12c458aed8e7b122e23a3a58Stephen Hines assignCalleeSavedSpillSlots(MachineFunction &MF, 122c6a4f5e819217e1e12c458aed8e7b122e23a3a58Stephen Hines const TargetRegisterInfo *TRI, 123c6a4f5e819217e1e12c458aed8e7b122e23a3a58Stephen Hines std::vector<CalleeSavedInfo> &CSI) const { 124c6a4f5e819217e1e12c458aed8e7b122e23a3a58Stephen Hines return false; 125c6a4f5e819217e1e12c458aed8e7b122e23a3a58Stephen Hines } 126c6a4f5e819217e1e12c458aed8e7b122e23a3a58Stephen Hines 1270098b3e2b69e527ddcf2ebad7a3081898fa3b4f0Evan Cheng /// getCalleeSavedSpillSlots - This method returns a pointer to an array of 1280098b3e2b69e527ddcf2ebad7a3081898fa3b4f0Evan Cheng /// pairs, that contains an entry for each callee saved register that must be 12909431e187f9abd45af08461df728204ee9731fd7Chris Lattner /// spilled to a particular stack location if it is spilled. 13009431e187f9abd45af08461df728204ee9731fd7Chris Lattner /// 13109431e187f9abd45af08461df728204ee9731fd7Chris Lattner /// Each entry in this array contains a <register,offset> pair, indicating the 13209431e187f9abd45af08461df728204ee9731fd7Chris Lattner /// fixed offset from the incoming stack pointer that each register should be 1338ff95de83cbe85d939535d2f4fb5f9b2b721081aTilmann Scheller /// spilled at. If a register is not listed here, the code generator is 13409431e187f9abd45af08461df728204ee9731fd7Chris Lattner /// allowed to spill it anywhere it chooses. 13534695381d626485a560594f162701088079589dfMisha Brukman /// 1368ff95de83cbe85d939535d2f4fb5f9b2b721081aTilmann Scheller virtual const SpillSlot * 1370098b3e2b69e527ddcf2ebad7a3081898fa3b4f0Evan Cheng getCalleeSavedSpillSlots(unsigned &NumEntries) const { 13809431e187f9abd45af08461df728204ee9731fd7Chris Lattner NumEntries = 0; 139dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines return nullptr; 14009431e187f9abd45af08461df728204ee9731fd7Chris Lattner } 14133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 14233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov /// targetHandlesStackFrameRounding - Returns true if the target is 14333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov /// responsible for rounding up the stack frame (probably at emitPrologue 14433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov /// time). 14533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov virtual bool targetHandlesStackFrameRounding() const { 14633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov return false; 14733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov } 14833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 149cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar /// Returns true if the target will correctly handle shrink wrapping. 150cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar virtual bool enableShrinkWrapping(const MachineFunction &MF) const { 151cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar return false; 152cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar } 153cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar 15433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov /// emitProlog/emitEpilog - These methods insert prolog and epilog code into 15533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov /// the function. 1566948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar virtual void emitPrologue(MachineFunction &MF, 1576948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar MachineBasicBlock &MBB) const = 0; 15833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov virtual void emitEpilogue(MachineFunction &MF, 15933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov MachineBasicBlock &MBB) const = 0; 160d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov 161cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar /// Replace a StackProbe stub (if any) with the actual probe code inline 162cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar virtual void inlineStackProbe(MachineFunction &MF, 163cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar MachineBasicBlock &PrologueMBB) const {} 164cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar 16576927d758657b3a511c73467ec5a7288795c1513Rafael Espindola /// Adjust the prologue to have the function use segmented stacks. This works 16676927d758657b3a511c73467ec5a7288795c1513Rafael Espindola /// by adding a check even before the "normal" function prologue. 1676948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar virtual void adjustForSegmentedStacks(MachineFunction &MF, 1686948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar MachineBasicBlock &PrologueMBB) const {} 16976927d758657b3a511c73467ec5a7288795c1513Rafael Espindola 17098fbe27ac8f0766ea94b89b8c03418131b72bea4Benjamin Kramer /// Adjust the prologue to add Erlang Run-Time System (ERTS) specific code in 17198fbe27ac8f0766ea94b89b8c03418131b72bea4Benjamin Kramer /// the assembly prologue to explicitly handle the stack. 1726948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar virtual void adjustForHiPEPrologue(MachineFunction &MF, 1736948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar MachineBasicBlock &PrologueMBB) const {} 17498fbe27ac8f0766ea94b89b8c03418131b72bea4Benjamin Kramer 175ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines /// Adjust the prologue to add an allocation at a fixed offset from the frame 176ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines /// pointer. 1776948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar virtual void 1786948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar adjustForFrameAllocatePrologue(MachineFunction &MF, 1796948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar MachineBasicBlock &PrologueMBB) const {} 180ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines 181cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov /// spillCalleeSavedRegisters - Issues instruction(s) to spill all callee 182cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov /// saved registers and returns true if it isn't possible / profitable to do 183cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov /// so by issuing a series of store instructions via 184cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov /// storeRegToStackSlot(). Returns false otherwise. 185cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov virtual bool spillCalleeSavedRegisters(MachineBasicBlock &MBB, 186cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov MachineBasicBlock::iterator MI, 187cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov const std::vector<CalleeSavedInfo> &CSI, 188cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov const TargetRegisterInfo *TRI) const { 189cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov return false; 190cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov } 191cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov 192cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov /// restoreCalleeSavedRegisters - Issues instruction(s) to restore all callee 193cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov /// saved registers and returns true if it isn't possible / profitable to do 194cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov /// so by issuing a series of load instructions via loadRegToStackSlot(). 195cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov /// Returns false otherwise. 196cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov virtual bool restoreCalleeSavedRegisters(MachineBasicBlock &MBB, 197cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov MachineBasicBlock::iterator MI, 198cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov const std::vector<CalleeSavedInfo> &CSI, 199cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov const TargetRegisterInfo *TRI) const { 200cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov return false; 201cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov } 202cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov 2036948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar /// Return true if the target needs to disable frame pointer elimination. 2046948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar virtual bool noFramePointerElim(const MachineFunction &MF) const; 2056948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar 206d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov /// hasFP - Return true if the specified function should have a dedicated 207d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov /// frame pointer register. For most targets this is true only if the function 208d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov /// has variable sized allocas or if frame pointer elimination is disabled. 209d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov virtual bool hasFP(const MachineFunction &MF) const = 0; 210d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov 211d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov /// hasReservedCallFrame - Under normal circumstances, when a frame pointer is 212d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov /// not required, we reserve argument space for call sites in the function 213d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov /// immediately on entry to the current function. This eliminates the need for 214d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov /// add/sub sp brackets around call sites. Returns true if the call frame is 215d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov /// included as part of the stack frame. 216d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov virtual bool hasReservedCallFrame(const MachineFunction &MF) const { 217d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov return !hasFP(MF); 218d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov } 219d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov 220d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov /// canSimplifyCallFramePseudos - When possible, it's best to simplify the 221d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov /// call frame pseudo ops before doing frame index elimination. This is 222d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov /// possible only when frame index references between the pseudos won't 223d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov /// need adjusting for the call frame adjustments. Normally, that's true 224d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov /// if the function has a reserved call frame or a frame pointer. Some 225d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov /// targets (Thumb2, for example) may have more complicated criteria, 226d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov /// however, and can override this behavior. 227d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov virtual bool canSimplifyCallFramePseudos(const MachineFunction &MF) const { 228d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov return hasReservedCallFrame(MF) || hasFP(MF); 229d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov } 230d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov 231ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines // needsFrameIndexResolution - Do we need to perform FI resolution for 232ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines // this function. Normally, this is required only when the function 233ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines // has any stack objects. However, targets may want to override this. 234ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines virtual bool needsFrameIndexResolution(const MachineFunction &MF) const; 235ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines 23682f58740c76b42af8370247b23677a0318f6dde8Anton Korobeynikov /// getFrameIndexReference - This method should return the base register 23782f58740c76b42af8370247b23677a0318f6dde8Anton Korobeynikov /// and offset used to reference a frame index location. The offset is 23882f58740c76b42af8370247b23677a0318f6dde8Anton Korobeynikov /// returned directly, and the base register is returned via FrameReg. 23982f58740c76b42af8370247b23677a0318f6dde8Anton Korobeynikov virtual int getFrameIndexReference(const MachineFunction &MF, int FI, 24082f58740c76b42af8370247b23677a0318f6dde8Anton Korobeynikov unsigned &FrameReg) const; 24194c5ae08750f314bc3cf1bf882b686244a3927d9Anton Korobeynikov 242ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines /// Same as above, except that the 'base register' will always be RSP, not 243cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar /// RBP on x86. This is generally used for emitting statepoint or EH tables 244cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar /// that use offsets from RSP. 245ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines /// TODO: This should really be a parameterizable choice. 246ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines virtual int getFrameIndexReferenceFromSP(const MachineFunction &MF, int FI, 247cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar unsigned &FrameReg) const { 248ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines // default to calling normal version, we override this on x86 only 249ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines llvm_unreachable("unimplemented for non-x86"); 250ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines return 0; 251ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines } 252ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines 253cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar /// This method determines which of the registers reported by 254cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar /// TargetRegisterInfo::getCalleeSavedRegs() should actually get saved. 255cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar /// The default implementation checks populates the \p SavedRegs bitset with 256cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar /// all registers which are modified in the function, targets may override 257cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar /// this function to save additional registers. 258cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar /// This method also sets up the register scavenger ensuring there is a free 259cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar /// register or a frameindex available. 260cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar virtual void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs, 261cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar RegScavenger *RS = nullptr) const; 26294c5ae08750f314bc3cf1bf882b686244a3927d9Anton Korobeynikov 26394c5ae08750f314bc3cf1bf882b686244a3927d9Anton Korobeynikov /// processFunctionBeforeFrameFinalized - This method is called immediately 26494c5ae08750f314bc3cf1bf882b686244a3927d9Anton Korobeynikov /// before the specified function's frame layout (MF.getFrameInfo()) is 26594c5ae08750f314bc3cf1bf882b686244a3927d9Anton Korobeynikov /// finalized. Once the frame is finalized, MO_FrameIndex operands are 26694c5ae08750f314bc3cf1bf882b686244a3927d9Anton Korobeynikov /// replaced with direct constants. This method is optional. 26794c5ae08750f314bc3cf1bf882b686244a3927d9Anton Korobeynikov /// 2683080d23fde4981835d8a7faf46c152441fadb11fHal Finkel virtual void processFunctionBeforeFrameFinalized(MachineFunction &MF, 269dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines RegScavenger *RS = nullptr) const { 27094c5ae08750f314bc3cf1bf882b686244a3927d9Anton Korobeynikov } 271700ed80d3da5e98e05ceb90e9bfb66058581a6dbEli Bendersky 272cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar virtual unsigned getWinEHParentFrameOffset(const MachineFunction &MF) const { 273cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar report_fatal_error("WinEH not implemented for this target"); 274cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar } 275cddc3e03e4ec99c0268c03a126195173e519ed58Pirama Arumuga Nainar 276700ed80d3da5e98e05ceb90e9bfb66058581a6dbEli Bendersky /// eliminateCallFramePseudoInstr - This method is called during prolog/epilog 277700ed80d3da5e98e05ceb90e9bfb66058581a6dbEli Bendersky /// code insertion to eliminate call frame setup and destroy pseudo 278700ed80d3da5e98e05ceb90e9bfb66058581a6dbEli Bendersky /// instructions (but only if the Target is using them). It is responsible 279700ed80d3da5e98e05ceb90e9bfb66058581a6dbEli Bendersky /// for eliminating these instructions, replacing them with concrete 280700ed80d3da5e98e05ceb90e9bfb66058581a6dbEli Bendersky /// instructions. This method need only be implemented if using call frame 281700ed80d3da5e98e05ceb90e9bfb66058581a6dbEli Bendersky /// setup/destroy pseudo instructions. 282700ed80d3da5e98e05ceb90e9bfb66058581a6dbEli Bendersky /// 283700ed80d3da5e98e05ceb90e9bfb66058581a6dbEli Bendersky virtual void 284700ed80d3da5e98e05ceb90e9bfb66058581a6dbEli Bendersky eliminateCallFramePseudoInstr(MachineFunction &MF, 285700ed80d3da5e98e05ceb90e9bfb66058581a6dbEli Bendersky MachineBasicBlock &MBB, 286700ed80d3da5e98e05ceb90e9bfb66058581a6dbEli Bendersky MachineBasicBlock::iterator MI) const { 287700ed80d3da5e98e05ceb90e9bfb66058581a6dbEli Bendersky llvm_unreachable("Call Frame Pseudo Instructions do not exist on this " 288700ed80d3da5e98e05ceb90e9bfb66058581a6dbEli Bendersky "target!"); 289700ed80d3da5e98e05ceb90e9bfb66058581a6dbEli Bendersky } 2906948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar 2916948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar /// Check whether or not the given \p MBB can be used as a prologue 2926948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar /// for the target. 2936948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar /// The prologue will be inserted first in this basic block. 2946948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar /// This method is used by the shrink-wrapping pass to decide if 2956948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar /// \p MBB will be correctly handled by the target. 2966948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar /// As soon as the target enable shrink-wrapping without overriding 2976948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar /// this method, we assume that each basic block is a valid 2986948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar /// prologue. 2996948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar virtual bool canUseAsPrologue(const MachineBasicBlock &MBB) const { 3006948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar return true; 3016948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar } 3026948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar 3036948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar /// Check whether or not the given \p MBB can be used as a epilogue 3046948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar /// for the target. 3056948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar /// The epilogue will be inserted before the first terminator of that block. 3066948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar /// This method is used by the shrink-wrapping pass to decide if 3076948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar /// \p MBB will be correctly handled by the target. 3086948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar /// As soon as the target enable shrink-wrapping without overriding 3096948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar /// this method, we assume that each basic block is a valid 3106948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar /// epilogue. 3116948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar virtual bool canUseAsEpilogue(const MachineBasicBlock &MBB) const { 3126948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar return true; 3136948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar } 3147cffcaaa48656fa6f90b041cc5f056304addef32Vikram S. Adve}; 3157cffcaaa48656fa6f90b041cc5f056304addef32Vikram S. Adve 316d0fde30ce850b78371fd1386338350591f9ff494Brian Gaeke} // End llvm namespace 317d0fde30ce850b78371fd1386338350591f9ff494Brian Gaeke 3187cffcaaa48656fa6f90b041cc5f056304addef32Vikram S. Adve#endif 319