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Simplify offset calculation of stack frame objects for $gp restore location and

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variable arguments in LowerCall and LowerFormalArguments. This should also fix
the bug in which handling of variable arguments is incorrect when the front-end
optimizes away unused fixed arguments.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131942 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Akira Hatanaka 2011-05-24 00:23:52 +00:00
parent a9b324be9c
commit b4d8d31e59
1 changed files with 31 additions and 56 deletions
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87
lib/Target/Mips/MipsISelLowering.cpp
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@ -13,6 +13,7 @@
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "mips-lower"
//#include <algorithm>
#include "MipsISelLowering.h"
#include "MipsMachineFunction.h"
#include "MipsTargetMachine.h"
@ -1064,7 +1065,6 @@ MipsTargetLowering::LowerCall(SDValue Chain, SDValue Callee,
// With EABI is it possible to have 16 args on registers.
SmallVector<std::pair<unsigned, SDValue>, 16> RegsToPass;
SmallVector<SDValue, 8> MemOpChains;
unsigned NextStackOffset = (Subtarget->isABI_EABI() ? 0 : 16);
MipsFI->setHasCall();
@ -1125,11 +1125,8 @@ MipsTargetLowering::LowerCall(SDValue Chain, SDValue Callee,
// This guarantees that when allocating Local Area the firsts
// 16 bytes which are alwayes reserved won't be overwritten
// if O32 ABI is used. For EABI the first address is zero.
unsigned ArgSize = VA.getValVT().getSizeInBits()/8;
NextStackOffset = VA.getLocMemOffset();
LastFI = MFI->CreateFixedObject(ArgSize, NextStackOffset, true);
NextStackOffset += ArgSize;
LastFI = MFI->CreateFixedObject(VA.getValVT().getSizeInBits()/8,
VA.getLocMemOffset(), true);
SDValue PtrOff = DAG.getFrameIndex(LastFI, getPointerTy());
// emit ISD::STORE whichs stores the
@ -1236,6 +1233,12 @@ MipsTargetLowering::LowerCall(SDValue Chain, SDValue Callee,
// Function can have an arbitrary number of calls, so
// hold the LastArgStackLoc with the biggest offset.
int MaxCallFrameSize = MipsFI->getMaxCallFrameSize();
unsigned NextStackOffset = CCInfo.getNextStackOffset();
// For O32, a minimum of four words (16 bytes) of argument space is
// allocated.
if (Subtarget->isABI_O32())
NextStackOffset = std::max(NextStackOffset, (unsigned)16);
if (MaxCallFrameSize < (int)NextStackOffset) {
MipsFI->setMaxCallFrameSize(NextStackOffset);
@ -1318,9 +1321,6 @@ MipsTargetLowering::LowerFormalArguments(SDValue Chain,
// Used with vargs to acumulate store chains.
std::vector<SDValue> OutChains;
// Keep track of the last register used for arguments
unsigned ArgRegEnd = 0;
// Assign locations to all of the incoming arguments.
SmallVector<CCValAssign, 16> ArgLocs;
CCState CCInfo(CallConv, isVarArg, getTargetMachine(),
@ -1331,8 +1331,6 @@ MipsTargetLowering::LowerFormalArguments(SDValue Chain,
else
CCInfo.AnalyzeFormalArguments(Ins, CC_Mips);
unsigned NextStackOffset = (Subtarget->isABI_EABI() ? 0 : 16);
EVT LastRegArgValVT;
int LastFI = 0;// MipsFI->LastInArgFI is 0 at the entry of this function.
for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
@ -1341,8 +1339,7 @@ MipsTargetLowering::LowerFormalArguments(SDValue Chain,
// Arguments stored on registers
if (VA.isRegLoc()) {
EVT RegVT = VA.getLocVT();
ArgRegEnd = VA.getLocReg();
LastRegArgValVT = VA.getValVT();
unsigned ArgReg = VA.getLocReg();
TargetRegisterClass *RC = 0;
if (RegVT == MVT::i32)
@ -1357,7 +1354,7 @@ MipsTargetLowering::LowerFormalArguments(SDValue Chain,
// Transform the arguments stored on
// physical registers into virtual ones
unsigned Reg = AddLiveIn(DAG.getMachineFunction(), ArgRegEnd, RC);
unsigned Reg = AddLiveIn(DAG.getMachineFunction(), ArgReg, RC);
SDValue ArgValue = DAG.getCopyFromReg(Chain, dl, Reg, RegVT);
// If this is an 8 or 16-bit value, it has been passed promoted
@ -1396,9 +1393,6 @@ MipsTargetLowering::LowerFormalArguments(SDValue Chain,
// sanity check
assert(VA.isMemLoc());
// The last argument is not a register anymore
ArgRegEnd = 0;
// The stack pointer offset is relative to the caller stack frame.
// Since the real stack size is unknown here, a negative SPOffset
// is used so there's a way to adjust these offsets when the stack
@ -1406,10 +1400,8 @@ MipsTargetLowering::LowerFormalArguments(SDValue Chain,
// used instead of a direct negative address (which is recorded to
// be used on emitPrologue) to avoid mis-calc of the first stack
// offset on PEI::calculateFrameObjectOffsets.
unsigned ArgSize = VA.getValVT().getSizeInBits()/8;
NextStackOffset = VA.getLocMemOffset();
LastFI = MFI->CreateFixedObject(ArgSize, NextStackOffset, true);
NextStackOffset += ArgSize;
LastFI = MFI->CreateFixedObject(VA.getValVT().getSizeInBits()/8,
VA.getLocMemOffset(), true);
// Create load nodes to retrieve arguments from the stack
SDValue FIN = DAG.getFrameIndex(LastFI, getPointerTy());
@ -1436,44 +1428,27 @@ MipsTargetLowering::LowerFormalArguments(SDValue Chain,
// must have their values written to the caller stack frame. If the last
// argument was placed in the stack, there's no need to save any register.
if (isVarArg && Subtarget->isABI_O32()) {
if (ArgRegEnd) {
// Last named formal argument is passed in register.
// Record the frame index of the first variable argument
// which is a value necessary to VASTART.
unsigned NextStackOffset = CCInfo.getNextStackOffset();
LastFI = MFI->CreateFixedObject(4, NextStackOffset, true);
MipsFI->setVarArgsFrameIndex(LastFI);
const unsigned O32IntRegs[] = {
Mips::A0, Mips::A1, Mips::A2, Mips::A3
};
// The last register argument that must be saved is Mips::A3
// Copy variable arguments passed in registers to stack.
for (; NextStackOffset < 16; NextStackOffset += 4) {
TargetRegisterClass *RC = Mips::CPURegsRegisterClass;
if (LastRegArgValVT == MVT::f64)
ArgRegEnd++;
if (ArgRegEnd < Mips::A3) {
// Both the last named formal argument and the first variable
// argument are passed in registers.
for (++ArgRegEnd; ArgRegEnd <= Mips::A3; ++ArgRegEnd) {
unsigned Reg = AddLiveIn(DAG.getMachineFunction(), ArgRegEnd, RC);
SDValue ArgValue = DAG.getCopyFromReg(Chain, dl, Reg, MVT::i32);
LastFI = MFI->CreateFixedObject(4, (ArgRegEnd-Mips::A0)*4, true);
SDValue PtrOff = DAG.getFrameIndex(LastFI, getPointerTy());
OutChains.push_back(DAG.getStore(Chain, dl, ArgValue, PtrOff,
MachinePointerInfo(),
false, false, 0));
// Record the frame index of the first variable argument
// which is a value necessary to VASTART.
if (!MipsFI->getVarArgsFrameIndex())
MipsFI->setVarArgsFrameIndex(LastFI);
}
} else {
// Last named formal argument is in register Mips::A3, and the first
// variable argument is on stack. Record the frame index of the first
// variable argument.
LastFI = MFI->CreateFixedObject(4, 16, true);
MipsFI->setVarArgsFrameIndex(LastFI);
}
} else {
// Last named formal argument and all the variable arguments are passed
// on stack. Record the frame index of the first variable argument.
unsigned Idx = NextStackOffset / 4;
unsigned Reg = AddLiveIn(DAG.getMachineFunction(), O32IntRegs[Idx], RC);
SDValue ArgValue = DAG.getCopyFromReg(Chain, dl, Reg, MVT::i32);
LastFI = MFI->CreateFixedObject(4, NextStackOffset, true);
MipsFI->setVarArgsFrameIndex(LastFI);
SDValue PtrOff = DAG.getFrameIndex(LastFI, getPointerTy());
OutChains.push_back(DAG.getStore(Chain, dl, ArgValue, PtrOff,
MachinePointerInfo(),
false, false, 0));
}
}