blob: be55e3b0a20baedb91f9b129dc14df5b9474ced3 [file] [log] [blame]
Chris Lattner5074bb52002-04-09 05:18:31 +00001//===-- PrologEpilogCodeInserter.cpp - Insert Prolog & Epilog code for fn -===//
2//
3// Insert SAVE/RESTORE instructions for the function
4//
5// Insert prolog code at the unique function entry point.
6// Insert epilog code at each function exit point.
7// InsertPrologEpilog invokes these only if the function is not compiled
8// with the leaf function optimization.
9//
10//===----------------------------------------------------------------------===//
11
12#include "SparcInternals.h"
13#include "SparcRegClassInfo.h"
Chris Lattnerd2a67df2002-12-28 20:16:08 +000014#include "llvm/CodeGen/MachineFunctionPass.h"
15#include "llvm/CodeGen/MachineFunctionInfo.h"
Chris Lattner5074bb52002-04-09 05:18:31 +000016#include "llvm/CodeGen/MachineCodeForInstruction.h"
Chris Lattnercbe63852002-10-28 21:43:57 +000017#include "llvm/CodeGen/MachineInstrBuilder.h"
Chris Lattner5074bb52002-04-09 05:18:31 +000018#include "llvm/Pass.h"
19#include "llvm/Function.h"
Chris Lattner5074bb52002-04-09 05:18:31 +000020
21namespace {
Chris Lattnerd2a67df2002-12-28 20:16:08 +000022 struct InsertPrologEpilogCode : public MachineFunctionPass {
Chris Lattner7076ff22002-06-25 16:13:21 +000023 const char *getPassName() const { return "Sparc Prolog/Epilog Inserter"; }
24
Chris Lattnerd2a67df2002-12-28 20:16:08 +000025 bool runOnMachineFunction(MachineFunction &F) {
26 if (!F.getInfo()->isCompiledAsLeafMethod()) {
Chris Lattner7076ff22002-06-25 16:13:21 +000027 InsertPrologCode(F);
28 InsertEpilogCode(F);
29 }
30 return false;
Chris Lattner5074bb52002-04-09 05:18:31 +000031 }
Chris Lattner7076ff22002-06-25 16:13:21 +000032
Chris Lattnerd2a67df2002-12-28 20:16:08 +000033 void InsertPrologCode(MachineFunction &F);
34 void InsertEpilogCode(MachineFunction &F);
Chris Lattner7076ff22002-06-25 16:13:21 +000035 };
Chris Lattner5074bb52002-04-09 05:18:31 +000036
37} // End anonymous namespace
38
39//------------------------------------------------------------------------
Chris Lattner5074bb52002-04-09 05:18:31 +000040// Create prolog and epilog code for procedure entry and exit
41//------------------------------------------------------------------------
42
Chris Lattnerd2a67df2002-12-28 20:16:08 +000043void InsertPrologEpilogCode::InsertPrologCode(MachineFunction &MF)
Chris Lattner5074bb52002-04-09 05:18:31 +000044{
Anand Shukla458496c2002-06-25 20:55:50 +000045 std::vector<MachineInstr*> mvec;
Chris Lattnerd2a67df2002-12-28 20:16:08 +000046 const TargetMachine &TM = MF.getTarget();
47 const TargetFrameInfo& frameInfo = TM.getFrameInfo();
Chris Lattner5074bb52002-04-09 05:18:31 +000048
49 // The second operand is the stack size. If it does not fit in the
50 // immediate field, we have to use a free register to hold the size.
Vikram S. Adve78044fb2002-10-13 00:24:06 +000051 // See the comments below for the choice of this register.
Chris Lattner5074bb52002-04-09 05:18:31 +000052 //
Chris Lattnerd2a67df2002-12-28 20:16:08 +000053 unsigned staticStackSize = MF.getInfo()->getStaticStackSize();
Chris Lattner5074bb52002-04-09 05:18:31 +000054
55 if (staticStackSize < (unsigned) frameInfo.getMinStackFrameSize())
56 staticStackSize = (unsigned) frameInfo.getMinStackFrameSize();
Vikram S. Adve78044fb2002-10-13 00:24:06 +000057
Chris Lattner5074bb52002-04-09 05:18:31 +000058 if (unsigned padsz = (staticStackSize %
59 (unsigned) frameInfo.getStackFrameSizeAlignment()))
60 staticStackSize += frameInfo.getStackFrameSizeAlignment() - padsz;
61
Chris Lattnercbe63852002-10-28 21:43:57 +000062 int32_t C = - (int) staticStackSize;
Chris Lattnerd2a67df2002-12-28 20:16:08 +000063 int SP = TM.getRegInfo().getStackPointer();
Misha Brukman56f4fa12003-05-20 20:32:24 +000064 if (TM.getInstrInfo().constantFitsInImmedField(V9::SAVE,staticStackSize)) {
65 mvec.push_back(BuildMI(V9::SAVE, 3).addMReg(SP).addSImm(C).addMReg(SP,
66 MOTy::Def));
Chris Lattnercbe63852002-10-28 21:43:57 +000067 } else {
Chris Lattnerd2a67df2002-12-28 20:16:08 +000068 // We have to put the stack size value into a register before SAVE.
69 // Use register %g1 since it is volatile across calls. Note that the
70 // local (%l) and in (%i) registers cannot be used before the SAVE!
71 // Do this by creating a code sequence equivalent to:
72 // SETSW -(stackSize), %g1
73 int uregNum = TM.getRegInfo().getUnifiedRegNum(
74 TM.getRegInfo().getRegClassIDOfType(Type::IntTy),
75 SparcIntRegClass::g1);
Chris Lattner5074bb52002-04-09 05:18:31 +000076
Misha Brukman56f4fa12003-05-20 20:32:24 +000077 MachineInstr* M = BuildMI(V9::SETHI, 2).addSImm(C)
78 .addMReg(uregNum, MOTy::Def);
Chris Lattnerd2a67df2002-12-28 20:16:08 +000079 M->setOperandHi32(0);
80 mvec.push_back(M);
81
Misha Brukman56f4fa12003-05-20 20:32:24 +000082 M = BuildMI(V9::OR, 3).addMReg(uregNum).addSImm(C)
83 .addMReg(uregNum, MOTy::Def);
Chris Lattnerd2a67df2002-12-28 20:16:08 +000084 M->setOperandLo32(1);
85 mvec.push_back(M);
86
Misha Brukman56f4fa12003-05-20 20:32:24 +000087 M = BuildMI(V9::SRA, 3).addMReg(uregNum).addZImm(0)
88 .addMReg(uregNum, MOTy::Def);
Chris Lattnerd2a67df2002-12-28 20:16:08 +000089 mvec.push_back(M);
90
91 // Now generate the SAVE using the value in register %g1
Misha Brukman56f4fa12003-05-20 20:32:24 +000092 M = BuildMI(V9::SAVE, 3).addMReg(SP).addMReg(uregNum).addMReg(SP,MOTy::Def);
Chris Lattnerd2a67df2002-12-28 20:16:08 +000093 mvec.push_back(M);
94 }
95
96 MF.front().insert(MF.front().begin(), mvec.begin(), mvec.end());
Chris Lattner5074bb52002-04-09 05:18:31 +000097}
98
Chris Lattnerd2a67df2002-12-28 20:16:08 +000099void InsertPrologEpilogCode::InsertEpilogCode(MachineFunction &MF)
Chris Lattner5074bb52002-04-09 05:18:31 +0000100{
Chris Lattnerd2a67df2002-12-28 20:16:08 +0000101 const TargetMachine &TM = MF.getTarget();
Chris Lattnerb4d58d72003-01-14 22:00:31 +0000102 const TargetInstrInfo &MII = TM.getInstrInfo();
Chris Lattnerd2a67df2002-12-28 20:16:08 +0000103
Misha Brukman181ea4a2002-10-28 20:01:13 +0000104 for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) {
105 MachineBasicBlock &MBB = *I;
106 BasicBlock &BB = *I->getBasicBlock();
107 Instruction *TermInst = (Instruction*)BB.getTerminator();
Chris Lattner5074bb52002-04-09 05:18:31 +0000108 if (TermInst->getOpcode() == Instruction::Ret)
Misha Brukman56f4fa12003-05-20 20:32:24 +0000109 {
110 int ZR = TM.getRegInfo().getZeroRegNum();
111 MachineInstr *Restore =
112 BuildMI(V9::RESTORE, 3).addMReg(ZR).addSImm(0).addMReg(ZR, MOTy::Def);
113
114 MachineCodeForInstruction &termMvec =
115 MachineCodeForInstruction::get(TermInst);
116
117 // Remove the NOPs in the delay slots of the return instruction
118 unsigned numNOPs = 0;
119 while (termMvec.back()->getOpCode() == V9::NOP)
Chris Lattner5074bb52002-04-09 05:18:31 +0000120 {
Misha Brukman56f4fa12003-05-20 20:32:24 +0000121 assert( termMvec.back() == MBB.back());
122 delete MBB.pop_back();
123 termMvec.pop_back();
124 ++numNOPs;
Chris Lattner5074bb52002-04-09 05:18:31 +0000125 }
Misha Brukman56f4fa12003-05-20 20:32:24 +0000126 assert(termMvec.back() == MBB.back());
127
128 // Check that we found the right number of NOPs and have the right
129 // number of instructions to replace them.
130 unsigned ndelays = MII.getNumDelaySlots(termMvec.back()->getOpCode());
131 assert(numNOPs == ndelays && "Missing NOPs in delay slots?");
132 assert(ndelays == 1 && "Cannot use epilog code for delay slots?");
133
134 // Append the epilog code to the end of the basic block.
135 MBB.push_back(Restore);
136 }
Chris Lattner5074bb52002-04-09 05:18:31 +0000137 }
138}
139
Vikram S. Adve36d3e032002-09-16 15:39:26 +0000140Pass* UltraSparc::getPrologEpilogInsertionPass() {
Chris Lattnerd2a67df2002-12-28 20:16:08 +0000141 return new InsertPrologEpilogCode();
Chris Lattner5074bb52002-04-09 05:18:31 +0000142}