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[X86] Convert esp-relative movs of function arguments to pushes, step 2

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This moves the transformation introduced in r223757 into a separate MI pass.
This allows it to cover many more cases (not only cases where there must be a 
reserved call frame), and perform rudimentary call folding. It still doesn't 
have a heuristic, so it is enabled only for optsize/minsize, with stack 
alignment <= 8, where it ought to be a fairly clear win.

Differential Revision: http://reviews.llvm.org/D6789

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227728 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Michael Kuperstein 2015-02-01 11:44:44 +00:00
parent 033773b057
commit 59d9986259
17 changed files with 8046 additions and 7486 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
include/llvm/Target/TargetFrameLowering.h
View File

@ -193,6 +193,11 @@ public:
return hasReservedCallFrame(MF) || hasFP(MF);
}
// needsFrameIndexResolution - Do we need to perform FI resolution for
// this function. Normally, this is required only when the function
// has any stack objects. However, targets may want to override this.
virtual bool needsFrameIndexResolution(const MachineFunction &MF) const;
/// getFrameIndexOffset - Returns the displacement from the frame register to
/// the stack frame of the specified index.
virtual int getFrameIndexOffset(const MachineFunction &MF, int FI) const;

20
lib/CodeGen/PrologEpilogInserter.cpp
View File

@ -703,7 +703,8 @@ void PEI::insertPrologEpilogCode(MachineFunction &Fn) {
/// register references and actual offsets.
///
void PEI::replaceFrameIndices(MachineFunction &Fn) {
if (!Fn.getFrameInfo()->hasStackObjects()) return; // Nothing to do?
const TargetFrameLowering &TFI = *Fn.getSubtarget().getFrameLowering();
if (!TFI.needsFrameIndexResolution(Fn)) return;
// Store SPAdj at exit of a basic block.
SmallVector<int, 8> SPState;
@ -769,13 +770,6 @@ void PEI::replaceFrameIndices(MachineBasicBlock *BB, MachineFunction &Fn,
continue;
}
// If we are looking at a call sequence, we need to keep track of
// the SP adjustment made by each instruction in the sequence.
// This includes both the frame setup/destroy pseudos (handled above),
// as well as other instructions that have side effects w.r.t the SP.
if (InsideCallSequence)
SPAdj += TII.getSPAdjust(I);
MachineInstr *MI = I;
bool DoIncr = true;
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
@ -854,6 +848,16 @@ void PEI::replaceFrameIndices(MachineBasicBlock *BB, MachineFunction &Fn,
break;
}
// If we are looking at a call sequence, we need to keep track of
// the SP adjustment made by each instruction in the sequence.
// This includes both the frame setup/destroy pseudos (handled above),
// as well as other instructions that have side effects w.r.t the SP.
// Note that this must come after eliminateFrameIndex, because
// if I itself referred to a frame index, we shouldn't count its own
// adjustment.
if (MI && InsideCallSequence)
SPAdj += TII.getSPAdjust(MI);
if (DoIncr && I != BB->end()) ++I;
// Update register states.

5
lib/CodeGen/TargetFrameLoweringImpl.cpp
View File

@ -42,3 +42,8 @@ int TargetFrameLowering::getFrameIndexReference(const MachineFunction &MF,
FrameReg = RI->getFrameRegister(MF);
return getFrameIndexOffset(MF, FI);
}
bool TargetFrameLowering::needsFrameIndexResolution(
const MachineFunction &MF) const {
return MF.getFrameInfo()->hasStackObjects();
}

107
lib/Target/X86/CMakeLists.txt
View File

@ -1,53 +1,54 @@
set(LLVM_TARGET_DEFINITIONS X86.td)
tablegen(LLVM X86GenRegisterInfo.inc -gen-register-info)
tablegen(LLVM X86GenDisassemblerTables.inc -gen-disassembler)
tablegen(LLVM X86GenInstrInfo.inc -gen-instr-info)
tablegen(LLVM X86GenAsmWriter.inc -gen-asm-writer)
tablegen(LLVM X86GenAsmWriter1.inc -gen-asm-writer -asmwriternum=1)
tablegen(LLVM X86GenAsmMatcher.inc -gen-asm-matcher)
tablegen(LLVM X86GenDAGISel.inc -gen-dag-isel)
tablegen(LLVM X86GenFastISel.inc -gen-fast-isel)
tablegen(LLVM X86GenCallingConv.inc -gen-callingconv)
tablegen(LLVM X86GenSubtargetInfo.inc -gen-subtarget)
add_public_tablegen_target(X86CommonTableGen)
set(sources
X86AsmPrinter.cpp
X86FastISel.cpp
X86FloatingPoint.cpp
X86FrameLowering.cpp
X86ISelDAGToDAG.cpp
X86ISelLowering.cpp
X86InstrInfo.cpp
X86MCInstLower.cpp
X86MachineFunctionInfo.cpp
X86PadShortFunction.cpp
X86RegisterInfo.cpp
X86SelectionDAGInfo.cpp
X86Subtarget.cpp
X86TargetMachine.cpp
X86TargetObjectFile.cpp
X86TargetTransformInfo.cpp
X86VZeroUpper.cpp
X86FixupLEAs.cpp
)
if( CMAKE_CL_64 )
enable_language(ASM_MASM)
ADD_CUSTOM_COMMAND(
OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/X86CompilationCallback_Win64.obj
MAIN_DEPENDENCY X86CompilationCallback_Win64.asm
COMMAND ${CMAKE_ASM_MASM_COMPILER} /Fo ${CMAKE_CURRENT_BINARY_DIR}/X86CompilationCallback_Win64.obj /c ${CMAKE_CURRENT_SOURCE_DIR}/X86CompilationCallback_Win64.asm
)
set(sources ${sources} ${CMAKE_CURRENT_BINARY_DIR}/X86CompilationCallback_Win64.obj)
endif()
add_llvm_target(X86CodeGen ${sources})
add_subdirectory(AsmParser)
add_subdirectory(Disassembler)
add_subdirectory(InstPrinter)
add_subdirectory(MCTargetDesc)
add_subdirectory(TargetInfo)
add_subdirectory(Utils)
set(LLVM_TARGET_DEFINITIONS X86.td)
tablegen(LLVM X86GenRegisterInfo.inc -gen-register-info)
tablegen(LLVM X86GenDisassemblerTables.inc -gen-disassembler)
tablegen(LLVM X86GenInstrInfo.inc -gen-instr-info)
tablegen(LLVM X86GenAsmWriter.inc -gen-asm-writer)
tablegen(LLVM X86GenAsmWriter1.inc -gen-asm-writer -asmwriternum=1)
tablegen(LLVM X86GenAsmMatcher.inc -gen-asm-matcher)
tablegen(LLVM X86GenDAGISel.inc -gen-dag-isel)
tablegen(LLVM X86GenFastISel.inc -gen-fast-isel)
tablegen(LLVM X86GenCallingConv.inc -gen-callingconv)
tablegen(LLVM X86GenSubtargetInfo.inc -gen-subtarget)
add_public_tablegen_target(X86CommonTableGen)
set(sources
X86AsmPrinter.cpp
X86CallFrameOptimization.cpp
X86FastISel.cpp
X86FloatingPoint.cpp
X86FrameLowering.cpp
X86ISelDAGToDAG.cpp
X86ISelLowering.cpp
X86InstrInfo.cpp
X86MCInstLower.cpp
X86MachineFunctionInfo.cpp
X86PadShortFunction.cpp
X86RegisterInfo.cpp
X86SelectionDAGInfo.cpp
X86Subtarget.cpp
X86TargetMachine.cpp
X86TargetObjectFile.cpp
X86TargetTransformInfo.cpp
X86VZeroUpper.cpp
X86FixupLEAs.cpp
)
if( CMAKE_CL_64 )
enable_language(ASM_MASM)
ADD_CUSTOM_COMMAND(
OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/X86CompilationCallback_Win64.obj
MAIN_DEPENDENCY X86CompilationCallback_Win64.asm
COMMAND ${CMAKE_ASM_MASM_COMPILER} /Fo ${CMAKE_CURRENT_BINARY_DIR}/X86CompilationCallback_Win64.obj /c ${CMAKE_CURRENT_SOURCE_DIR}/X86CompilationCallback_Win64.asm
)
set(sources ${sources} ${CMAKE_CURRENT_BINARY_DIR}/X86CompilationCallback_Win64.obj)
endif()
add_llvm_target(X86CodeGen ${sources})
add_subdirectory(AsmParser)
add_subdirectory(Disassembler)
add_subdirectory(InstPrinter)
add_subdirectory(MCTargetDesc)
add_subdirectory(TargetInfo)
add_subdirectory(Utils)

5
lib/Target/X86/X86.h
View File

@ -64,6 +64,11 @@ FunctionPass *createX86PadShortFunctions();
/// to eliminate execution delays in some Atom processors.
FunctionPass *createX86FixupLEAs();
/// createX86CallFrameOptimization - Return a pass that optimizes
/// the code-size of x86 call sequences. This is done by replacing
/// esp-relative movs with pushes.
FunctionPass *createX86CallFrameOptimization();
} // End llvm namespace
#endif

400
lib/Target/X86/X86CallFrameOptimization.cpp Normal file
View File

@ -0,0 +1,400 @@
//===----- X86CallFrameOptimization.cpp - Optimize x86 call sequences -----===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines a pass that optimizes call sequences on x86.
// Currently, it converts movs of function parameters onto the stack into
// pushes. This is beneficial for two main reasons:
// 1) The push instruction encoding is much smaller than an esp-relative mov
// 2) It is possible to push memory arguments directly. So, if the
// the transformation is preformed pre-reg-alloc, it can help relieve
// register pressure.
//
//===----------------------------------------------------------------------===//
#include <algorithm>
#include "X86.h"
#include "X86InstrInfo.h"
#include "X86Subtarget.h"
#include "X86MachineFunctionInfo.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/IR/Function.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetInstrInfo.h"
using namespace llvm;
#define DEBUG_TYPE "x86-cf-opt"
cl::opt<bool> NoX86CFOpt("no-x86-call-frame-opt",
cl::desc("Avoid optimizing x86 call frames for size"),
cl::init(false), cl::Hidden);
namespace {
class X86CallFrameOptimization : public MachineFunctionPass {
public:
X86CallFrameOptimization() : MachineFunctionPass(ID) {}
bool runOnMachineFunction(MachineFunction &MF) override;
private:
bool shouldPerformTransformation(MachineFunction &MF);
bool adjustCallSequence(MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator I);
MachineInstr *canFoldIntoRegPush(MachineBasicBlock::iterator FrameSetup,
unsigned Reg);
const char *getPassName() const override {
return "X86 Optimize Call Frame";
}
const TargetInstrInfo *TII;
const TargetFrameLowering *TFL;
const MachineRegisterInfo *MRI;
static char ID;
};
char X86CallFrameOptimization::ID = 0;
}
FunctionPass *llvm::createX86CallFrameOptimization() {
return new X86CallFrameOptimization();
}
// This checks whether the transformation is legal and profitable
bool X86CallFrameOptimization::shouldPerformTransformation(MachineFunction &MF) {
if (NoX86CFOpt.getValue())
return false;
// We currently only support call sequences where *all* parameters.
// are passed on the stack.
// No point in running this in 64-bit mode, since some arguments are
// passed in-register in all common calling conventions, so the pattern
// we're looking for will never match.
const X86Subtarget &STI = MF.getTarget().getSubtarget<X86Subtarget>();
if (STI.is64Bit())
return false;
// You would expect straight-line code between call-frame setup and
// call-frame destroy. You would be wrong. There are circumstances (e.g.
// CMOV_GR8 expansion of a select that feeds a function call!) where we can
// end up with the setup and the destroy in different basic blocks.
// This is bad, and breaks SP adjustment.
// So, check that all of the frames in the function are closed inside
// the same block, and, for good measure, that there are no nested frames.
int FrameSetupOpcode = TII->getCallFrameSetupOpcode();
int FrameDestroyOpcode = TII->getCallFrameDestroyOpcode();
for (MachineBasicBlock &BB : MF) {
bool InsideFrameSequence = false;
for (MachineInstr &MI : BB) {
if (MI.getOpcode() == FrameSetupOpcode) {
if (InsideFrameSequence)
return false;
InsideFrameSequence = true;
}
else if (MI.getOpcode() == FrameDestroyOpcode) {
if (!InsideFrameSequence)
return false;
InsideFrameSequence = false;
}
}
if (InsideFrameSequence)
return false;
}
// Now that we know the transformation is legal, check if it is
// profitable.
// TODO: Add a heuristic that actually looks at the function,
// and enable this for more cases.
// This transformation is always a win when we expected to have
// a reserved call frame. Under other circumstances, it may be either
// a win or a loss, and requires a heuristic.
// For now, enable it only for the relatively clear win cases.
bool CannotReserveFrame = MF.getFrameInfo()->hasVarSizedObjects();
if (CannotReserveFrame)
return true;
// For now, don't even try to evaluate the profitability when
// not optimizing for size.
AttributeSet FnAttrs = MF.getFunction()->getAttributes();
bool OptForSize =
FnAttrs.hasAttribute(AttributeSet::FunctionIndex,
Attribute::OptimizeForSize) ||
FnAttrs.hasAttribute(AttributeSet::FunctionIndex, Attribute::MinSize);
if (!OptForSize)
return false;
// Stack re-alignment can make this unprofitable even in terms of size.
// As mentioned above, a better heuristic is needed. For now, don't do this
// when the required alignment is above 8. (4 would be the safe choice, but
// some experimentation showed 8 is generally good).
if (TFL->getStackAlignment() > 8)
return false;
return true;
}
bool X86CallFrameOptimization::runOnMachineFunction(MachineFunction &MF) {
TII = MF.getSubtarget().getInstrInfo();
TFL = MF.getSubtarget().getFrameLowering();
MRI = &MF.getRegInfo();
if (!shouldPerformTransformation(MF))
return false;
int FrameSetupOpcode = TII->getCallFrameSetupOpcode();
bool Changed = false;
for (MachineFunction::iterator BB = MF.begin(), E = MF.end(); BB != E; ++BB)
for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); ++I)
if (I->getOpcode() == FrameSetupOpcode)
Changed |= adjustCallSequence(MF, *BB, I);
return Changed;
}
bool X86CallFrameOptimization::adjustCallSequence(MachineFunction &MF,
MachineBasicBlock &MBB,
MachineBasicBlock::iterator I) {
// Check that this particular call sequence is amenable to the
// transformation.
const X86RegisterInfo &RegInfo = *static_cast<const X86RegisterInfo *>(
MF.getSubtarget().getRegisterInfo());
unsigned StackPtr = RegInfo.getStackRegister();
int FrameDestroyOpcode = TII->getCallFrameDestroyOpcode();
// We expect to enter this at the beginning of a call sequence
assert(I->getOpcode() == TII->getCallFrameSetupOpcode());
MachineBasicBlock::iterator FrameSetup = I++;
// For globals in PIC mode, we can have some LEAs here.
// Ignore them, they don't bother us.
// TODO: Extend this to something that covers more cases.
while (I->getOpcode() == X86::LEA32r)
++I;
// We expect a copy instruction here.
// TODO: The copy instruction is a lowering artifact.
// We should also support a copy-less version, where the stack
// pointer is used directly.
if (!I->isCopy() || !I->getOperand(0).isReg())
return false;
MachineBasicBlock::iterator SPCopy = I++;
StackPtr = SPCopy->getOperand(0).getReg();
// Scan the call setup sequence for the pattern we're looking for.
// We only handle a simple case - a sequence of MOV32mi or MOV32mr
// instructions, that push a sequence of 32-bit values onto the stack, with
// no gaps between them.
SmallVector<MachineInstr*, 4> MovVector(4, nullptr);
unsigned int MaxAdjust = FrameSetup->getOperand(0).getImm() / 4;
if (MaxAdjust > 4)
MovVector.resize(MaxAdjust, nullptr);
do {
int Opcode = I->getOpcode();
if (Opcode != X86::MOV32mi && Opcode != X86::MOV32mr)
break;
// We only want movs of the form:
// movl imm/r32, k(%esp)
// If we run into something else, bail.
// Note that AddrBaseReg may, counter to its name, not be a register,
// but rather a frame index.
// TODO: Support the fi case. This should probably work now that we
// have the infrastructure to track the stack pointer within a call
// sequence.
if (!I->getOperand(X86::AddrBaseReg).isReg() ||
(I->getOperand(X86::AddrBaseReg).getReg() != StackPtr) ||
!I->getOperand(X86::AddrScaleAmt).isImm() ||
(I->getOperand(X86::AddrScaleAmt).getImm() != 1) ||
(I->getOperand(X86::AddrIndexReg).getReg() != X86::NoRegister) ||
(I->getOperand(X86::AddrSegmentReg).getReg() != X86::NoRegister) ||
!I->getOperand(X86::AddrDisp).isImm())
return false;
int64_t StackDisp = I->getOperand(X86::AddrDisp).getImm();
assert(StackDisp >= 0 && "Negative stack displacement when passing parameters");
// We really don't want to consider the unaligned case.
if (StackDisp % 4)
return false;
StackDisp /= 4;
assert((size_t)StackDisp < MovVector.size() &&
"Function call has more parameters than the stack is adjusted for.");
// If the same stack slot is being filled twice, something's fishy.
if (MovVector[StackDisp] != nullptr)
return false;
MovVector[StackDisp] = I;
++I;
} while (I != MBB.end());
// We now expect the end of the sequence - a call and a stack adjust.
if (I == MBB.end())
return false;
// For PCrel calls, we expect an additional COPY of the basereg.
// If we find one, skip it.
if (I->isCopy()) {
if (I->getOperand(1).getReg() ==
MF.getInfo<X86MachineFunctionInfo>()->getGlobalBaseReg())
++I;
else
return false;
}
if (!I->isCall())
return false;
MachineBasicBlock::iterator Call = I;
if ((++I)->getOpcode() != FrameDestroyOpcode)
return false;
// Now, go through the vector, and see that we don't have any gaps,
// but only a series of 32-bit MOVs.
int64_t ExpectedDist = 0;
auto MMI = MovVector.begin(), MME = MovVector.end();
for (; MMI != MME; ++MMI, ExpectedDist += 4)
if (*MMI == nullptr)
break;
// If the call had no parameters, do nothing
if (!ExpectedDist)
return false;
// We are either at the last parameter, or a gap.
// Make sure it's not a gap
for (; MMI != MME; ++MMI)
if (*MMI != nullptr)
return false;
// Ok, we can in fact do the transformation for this call.
// Do not remove the FrameSetup instruction, but adjust the parameters.
// PEI will end up finalizing the handling of this.
FrameSetup->getOperand(1).setImm(ExpectedDist);
DebugLoc DL = I->getDebugLoc();
// Now, iterate through the vector in reverse order, and replace the movs
// with pushes. MOVmi/MOVmr doesn't have any defs, so no need to
// replace uses.
for (int Idx = (ExpectedDist / 4) - 1; Idx >= 0; --Idx) {
MachineBasicBlock::iterator MOV = *MovVector[Idx];
MachineOperand PushOp = MOV->getOperand(X86::AddrNumOperands);
if (MOV->getOpcode() == X86::MOV32mi) {
unsigned PushOpcode = X86::PUSHi32;
// If the operand is a small (8-bit) immediate, we can use a
// PUSH instruction with a shorter encoding.
// Note that isImm() may fail even though this is a MOVmi, because
// the operand can also be a symbol.
if (PushOp.isImm()) {
int64_t Val = PushOp.getImm();
if (isInt<8>(Val))
PushOpcode = X86::PUSH32i8;
}
BuildMI(MBB, Call, DL, TII->get(PushOpcode)).addOperand(PushOp);
} else {
unsigned int Reg = PushOp.getReg();
// If PUSHrmm is not slow on this target, try to fold the source of the
// push into the instruction.
const X86Subtarget &ST = MF.getTarget().getSubtarget<X86Subtarget>();
bool SlowPUSHrmm = ST.isAtom() || ST.isSLM();
// Check that this is legal to fold. Right now, we're extremely
// conservative about that.
MachineInstr *DefMov = nullptr;
if (!SlowPUSHrmm && (DefMov = canFoldIntoRegPush(FrameSetup, Reg))) {
MachineInstr *Push = BuildMI(MBB, Call, DL, TII->get(X86::PUSH32rmm));
unsigned NumOps = DefMov->getDesc().getNumOperands();
for (unsigned i = NumOps - X86::AddrNumOperands; i != NumOps; ++i)
Push->addOperand(DefMov->getOperand(i));
DefMov->eraseFromParent();
} else {
BuildMI(MBB, Call, DL, TII->get(X86::PUSH32r)).addReg(Reg).getInstr();
}
}
MBB.erase(MOV);
}
// The stack-pointer copy is no longer used in the call sequences.
// There should not be any other users, but we can't commit to that, so:
if (MRI->use_empty(SPCopy->getOperand(0).getReg()))
SPCopy->eraseFromParent();
// Once we've done this, we need to make sure PEI doesn't assume a reserved
// frame.
X86MachineFunctionInfo *FuncInfo = MF.getInfo<X86MachineFunctionInfo>();
FuncInfo->setHasPushSequences(true);
return true;
}
MachineInstr *X86CallFrameOptimization::canFoldIntoRegPush(
MachineBasicBlock::iterator FrameSetup, unsigned Reg) {
// Do an extremely restricted form of load folding.
// ISel will often create patterns like:
// movl 4(%edi), %eax
// movl 8(%edi), %ecx
// movl 12(%edi), %edx
// movl %edx, 8(%esp)
// movl %ecx, 4(%esp)
// movl %eax, (%esp)
// call
// Get rid of those with prejudice.
if (!TargetRegisterInfo::isVirtualRegister(Reg))
return nullptr;
// Make sure this is the only use of Reg.
if (!MRI->hasOneNonDBGUse(Reg))
return nullptr;
MachineBasicBlock::iterator DefMI = MRI->getVRegDef(Reg);
// Make sure the def is a MOV from memory.
// If the def is an another block, give up.
if (DefMI->getOpcode() != X86::MOV32rm ||
DefMI->getParent() != FrameSetup->getParent())
return nullptr;
// Be careful with movs that load from a stack slot, since it may get
// resolved incorrectly.
// TODO: Again, we already have the infrastructure, so this should work.
if (!DefMI->getOperand(1).isReg())
return nullptr;
// Now, make sure everything else up until the ADJCALLSTACK is a sequence
// of MOVs. To be less conservative would require duplicating a lot of the
// logic from PeepholeOptimizer.
// FIXME: A possibly better approach would be to teach the PeepholeOptimizer
// to be smarter about folding into pushes.
for (auto I = DefMI; I != FrameSetup; ++I)
if (I->getOpcode() != X86::MOV32rm)
return nullptr;
return DefMI;
}

6716
lib/Target/X86/X86FastISel.cpp
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File diff suppressed because it is too large Load Diff

4123
lib/Target/X86/X86FrameLowering.cpp
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File diff suppressed because it is too large Load Diff

192
lib/Target/X86/X86FrameLowering.h
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@ -1,95 +1,97 @@
//===-- X86TargetFrameLowering.h - Define frame lowering for X86 -*- C++ -*-==//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This class implements X86-specific bits of TargetFrameLowering class.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_TARGET_X86_X86FRAMELOWERING_H
#define LLVM_LIB_TARGET_X86_X86FRAMELOWERING_H
#include "llvm/Target/TargetFrameLowering.h"
namespace llvm {
class MCSymbol;
class X86TargetMachine;
class X86Subtarget;
class X86FrameLowering : public TargetFrameLowering {
public:
explicit X86FrameLowering(StackDirection D, unsigned StackAl, int LAO)
: TargetFrameLowering(StackGrowsDown, StackAl, LAO) {}
/// Emit a call to the target's stack probe function. This is required for all
/// large stack allocations on Windows. The caller is required to materialize
/// the number of bytes to probe in RAX/EAX.
static void emitStackProbeCall(MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI, DebugLoc DL);
void emitCalleeSavedFrameMoves(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
DebugLoc DL) const;
/// emitProlog/emitEpilog - These methods insert prolog and epilog code into
/// the function.
void emitPrologue(MachineFunction &MF) const override;
void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
void adjustForSegmentedStacks(MachineFunction &MF) const override;
void adjustForHiPEPrologue(MachineFunction &MF) const override;
void processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
RegScavenger *RS = nullptr) const override;
bool
assignCalleeSavedSpillSlots(MachineFunction &MF,
const TargetRegisterInfo *TRI,
std::vector<CalleeSavedInfo> &CSI) const override;
bool spillCalleeSavedRegisters(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
const std::vector<CalleeSavedInfo> &CSI,
const TargetRegisterInfo *TRI) const override;
bool restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
const std::vector<CalleeSavedInfo> &CSI,
const TargetRegisterInfo *TRI) const override;
bool hasFP(const MachineFunction &MF) const override;
bool hasReservedCallFrame(const MachineFunction &MF) const override;
int getFrameIndexOffset(const MachineFunction &MF, int FI) const override;
int getFrameIndexReference(const MachineFunction &MF, int FI,
unsigned &FrameReg) const override;
int getFrameIndexOffsetFromSP(const MachineFunction &MF, int FI) const;
int getFrameIndexReferenceFromSP(const MachineFunction &MF, int FI,
unsigned &FrameReg) const override;
void eliminateCallFramePseudoInstr(MachineFunction &MF,
MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI) const override;
private:
/// convertArgMovsToPushes - This method tries to convert a call sequence
/// that uses sub and mov instructions to put the argument onto the stack
/// into a series of pushes.
/// Returns true if the transformation succeeded, false if not.
bool convertArgMovsToPushes(MachineFunction &MF,
MachineBasicBlock &MBB,
MachineBasicBlock::iterator I,
uint64_t Amount) const;
};
} // End llvm namespace
#endif
//===-- X86TargetFrameLowering.h - Define frame lowering for X86 -*- C++ -*-==//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This class implements X86-specific bits of TargetFrameLowering class.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_TARGET_X86_X86FRAMELOWERING_H
#define LLVM_LIB_TARGET_X86_X86FRAMELOWERING_H
#include "llvm/Target/TargetFrameLowering.h"
namespace llvm {
class MCSymbol;
class X86TargetMachine;
class X86Subtarget;
class X86FrameLowering : public TargetFrameLowering {
public:
explicit X86FrameLowering(StackDirection D, unsigned StackAl, int LAO)
: TargetFrameLowering(StackGrowsDown, StackAl, LAO) {}
/// Emit a call to the target's stack probe function. This is required for all
/// large stack allocations on Windows. The caller is required to materialize
/// the number of bytes to probe in RAX/EAX.
static void emitStackProbeCall(MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI, DebugLoc DL);
void emitCalleeSavedFrameMoves(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
DebugLoc DL) const;
/// emitProlog/emitEpilog - These methods insert prolog and epilog code into
/// the function.
void emitPrologue(MachineFunction &MF) const override;
void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
void adjustForSegmentedStacks(MachineFunction &MF) const override;
void adjustForHiPEPrologue(MachineFunction &MF) const override;
void processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
RegScavenger *RS = nullptr) const override;
bool
assignCalleeSavedSpillSlots(MachineFunction &MF,
const TargetRegisterInfo *TRI,
std::vector<CalleeSavedInfo> &CSI) const override;
bool spillCalleeSavedRegisters(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
const std::vector<CalleeSavedInfo> &CSI,
const TargetRegisterInfo *TRI) const override;
bool restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
const std::vector<CalleeSavedInfo> &CSI,
const TargetRegisterInfo *TRI) const override;
bool hasFP(const MachineFunction &MF) const override;
bool hasReservedCallFrame(const MachineFunction &MF) const override;
bool canSimplifyCallFramePseudos(const MachineFunction &MF) const override;
bool needsFrameIndexResolution(const MachineFunction &MF) const override;
int getFrameIndexOffset(const MachineFunction &MF, int FI) const override;
int getFrameIndexReference(const MachineFunction &MF, int FI,
unsigned &FrameReg) const override;
int getFrameIndexOffsetFromSP(const MachineFunction &MF, int FI) const;
int getFrameIndexReferenceFromSP(const MachineFunction &MF, int FI,
unsigned &FrameReg) const override;
void eliminateCallFramePseudoInstr(MachineFunction &MF,
MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI) const override;
private:
/// convertArgMovsToPushes - This method tries to convert a call sequence
/// that uses sub and mov instructions to put the argument onto the stack
/// into a series of pushes.
/// Returns true if the transformation succeeded, false if not.
bool convertArgMovsToPushes(MachineFunction &MF,
MachineBasicBlock &MBB,
MachineBasicBlock::iterator I,
uint64_t Amount) const;
};
} // End llvm namespace
#endif

3700
lib/Target/X86/X86InstrCompiler.td
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File diff suppressed because it is too large Load Diff

52
lib/Target/X86/X86InstrInfo.cpp
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@ -1804,6 +1804,58 @@ X86InstrInfo::isCoalescableExtInstr(const MachineInstr &MI,
return false;
}
int X86InstrInfo::getSPAdjust(const MachineInstr *MI) const {
const MachineFunction *MF = MI->getParent()->getParent();
const TargetFrameLowering *TFI = MF->getSubtarget().getFrameLowering();
if (MI->getOpcode() == getCallFrameSetupOpcode() ||
MI->getOpcode() == getCallFrameDestroyOpcode()) {
unsigned StackAlign = TFI->getStackAlignment();
int SPAdj = (MI->getOperand(0).getImm() + StackAlign - 1) / StackAlign *
StackAlign;
SPAdj -= MI->getOperand(1).getImm();
if (MI->getOpcode() == getCallFrameSetupOpcode())
return SPAdj;
else
return -SPAdj;
}
// To know whether a call adjusts the stack, we need information
// that is bound to the following ADJCALLSTACKUP pseudo.
// Look for the next ADJCALLSTACKUP that follows the call.
if (MI->isCall()) {
const MachineBasicBlock* MBB = MI->getParent();
auto I = ++MachineBasicBlock::const_iterator(MI);
for (auto E = MBB->end(); I != E; ++I) {
if (I->getOpcode() == getCallFrameDestroyOpcode() ||
I->isCall())
break;
}
// If we could not find a frame destroy opcode, then it has already
// been simplified, so we don't care.
if (I->getOpcode() != getCallFrameDestroyOpcode())
return 0;
return -(I->getOperand(1).getImm());
}
// Currently handle only PUSHes we can reasonably expect to see
// in call sequences
switch (MI->getOpcode()) {
default:
return 0;
case X86::PUSH32i8:
case X86::PUSH32r:
case X86::PUSH32rmm:
case X86::PUSH32rmr:
case X86::PUSHi32:
return 4;
}
}
/// isFrameOperand - Return true and the FrameIndex if the specified
/// operand and follow operands form a reference to the stack frame.
bool X86InstrInfo::isFrameOperand(const MachineInstr *MI, unsigned int Op,

5
lib/Target/X86/X86InstrInfo.h
View File

@ -175,6 +175,11 @@ public:
///
const X86RegisterInfo &getRegisterInfo() const { return RI; }
/// getSPAdjust - This returns the stack pointer adjustment made by
/// this instruction. For x86, we need to handle more complex call
/// sequences involving PUSHes.
int getSPAdjust(const MachineInstr *MI) const override;
/// isCoalescableExtInstr - Return true if the instruction is a "coalescable"
/// extension instruction. That is, it's like a copy where it's legal for the
/// source to overlap the destination. e.g. X86::MOVSX64rr32. If this returns

12
lib/Target/X86/X86MachineFunctionInfo.h
View File

@ -77,6 +77,9 @@ class X86MachineFunctionInfo : public MachineFunctionInfo {
unsigned ArgumentStackSize;
/// NumLocalDynamics - Number of local-dynamic TLS accesses.
unsigned NumLocalDynamics;
/// HasPushSequences - Keeps track of whether this function uses sequences
/// of pushes to pass function parameters.
bool HasPushSequences;
private:
/// ForwardedMustTailRegParms - A list of virtual and physical registers
@ -97,7 +100,8 @@ public:
VarArgsGPOffset(0),
VarArgsFPOffset(0),
ArgumentStackSize(0),
NumLocalDynamics(0) {}
NumLocalDynamics(0),
HasPushSequences(false) {}
explicit X86MachineFunctionInfo(MachineFunction &MF)
: ForceFramePointer(false),
@ -113,11 +117,15 @@ public:
VarArgsGPOffset(0),
VarArgsFPOffset(0),
ArgumentStackSize(0),
NumLocalDynamics(0) {}
NumLocalDynamics(0),
HasPushSequences(false) {}
bool getForceFramePointer() const { return ForceFramePointer;}
void setForceFramePointer(bool forceFP) { ForceFramePointer = forceFP; }
bool getHasPushSequences() const { return HasPushSequences; }
void setHasPushSequences(bool HasPush) { HasPushSequences = HasPush; }
bool getRestoreBasePointer() const { return RestoreBasePointerOffset!=0; }
void setRestoreBasePointer(const MachineFunction *MF);
int getRestoreBasePointerOffset() const {return RestoreBasePointerOffset; }

5
lib/Target/X86/X86RegisterInfo.cpp
View File

@ -468,8 +468,6 @@ void
X86RegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
int SPAdj, unsigned FIOperandNum,
RegScavenger *RS) const {
assert(SPAdj == 0 && "Unexpected");
MachineInstr &MI = *II;
MachineFunction &MF = *MI.getParent()->getParent();
const TargetFrameLowering *TFI = MF.getSubtarget().getFrameLowering();
@ -506,6 +504,9 @@ X86RegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
} else
FIOffset = TFI->getFrameIndexOffset(MF, FrameIndex);
if (BasePtr == StackPtr)
FIOffset += SPAdj;
// The frame index format for stackmaps and patchpoints is different from the
// X86 format. It only has a FI and an offset.
if (Opc == TargetOpcode::STACKMAP || Opc == TargetOpcode::PATCHPOINT) {

5
lib/Target/X86/X86TargetMachine.cpp
View File

@ -192,6 +192,7 @@ public:
void addIRPasses() override;
bool addInstSelector() override;
bool addILPOpts() override;
void addPreRegAlloc() override;
void addPostRegAlloc() override;
void addPreEmitPass() override;
};
@ -225,6 +226,10 @@ bool X86PassConfig::addILPOpts() {
return true;
}
void X86PassConfig::addPreRegAlloc() {
addPass(createX86CallFrameOptimization());
}
void X86PassConfig::addPostRegAlloc() {
addPass(createX86FloatingPointStackifierPass());
}

2
test/CodeGen/X86/inalloca-invoke.ll
View File

@ -31,7 +31,7 @@ blah:
to label %invoke.cont unwind label %lpad
; Uses end as sret param.
; CHECK: movl %[[end]], (%esp)
; CHECK: pushl %[[end]]
; CHECK: calll _plus
invoke.cont:

178
test/CodeGen/X86/movtopush.ll
View File

@ -1,24 +1,65 @@
; RUN: llc < %s -mtriple=i686-windows | FileCheck %s -check-prefix=NORMAL
; RUN: llc < %s -mtriple=x86_64-windows | FileCheck %s -check-prefix=X64
; RUN: llc < %s -mtriple=i686-windows -force-align-stack -stack-alignment=32 | FileCheck %s -check-prefix=ALIGNED
declare void @good(i32 %a, i32 %b, i32 %c, i32 %d)
declare void @inreg(i32 %a, i32 inreg %b, i32 %c, i32 %d)
; Here, we should have a reserved frame, so we don't expect pushes
; NORMAL-LABEL: test1
; NORMAL-LABEL: test1:
; NORMAL: subl $16, %esp
; NORMAL-NEXT: movl $4, 12(%esp)
; NORMAL-NEXT: movl $3, 8(%esp)
; NORMAL-NEXT: movl $2, 4(%esp)
; NORMAL-NEXT: movl $1, (%esp)
; NORMAL-NEXT: call
; NORMAL-NEXT: addl $16, %esp
define void @test1() {
entry:
call void @good(i32 1, i32 2, i32 3, i32 4)
ret void
}
; Here, we expect a sequence of 4 immediate pushes
; NORMAL-LABEL: test2
; We're optimizing for code size, so we should get pushes for x86,
; even though there is a reserved call frame.
; Make sure we don't touch x86-64
; NORMAL-LABEL: test1b:
; NORMAL-NOT: subl {{.*}} %esp
; NORMAL: pushl $4
; NORMAL-NEXT: pushl $3
; NORMAL-NEXT: pushl $2
; NORMAL-NEXT: pushl $1
; NORMAL-NEXT: call
; NORMAL-NEXT: addl $16, %esp
; X64-LABEL: test1b:
; X64: movl $1, %ecx
; X64-NEXT: movl $2, %edx
; X64-NEXT: movl $3, %r8d
; X64-NEXT: movl $4, %r9d
; X64-NEXT: callq good
define void @test1b() optsize {
entry:
call void @good(i32 1, i32 2, i32 3, i32 4)
ret void
}
; Same as above, but for minsize
; NORMAL-LABEL: test1c:
; NORMAL-NOT: subl {{.*}} %esp
; NORMAL: pushl $4
; NORMAL-NEXT: pushl $3
; NORMAL-NEXT: pushl $2
; NORMAL-NEXT: pushl $1
; NORMAL-NEXT: call
; NORMAL-NEXT: addl $16, %esp
define void @test1c() minsize {
entry:
call void @good(i32 1, i32 2, i32 3, i32 4)
ret void
}
; If we have a reserved frame, we should have pushes
; NORMAL-LABEL: test2:
; NORMAL-NOT: subl {{.*}} %esp
; NORMAL: pushl $4
; NORMAL-NEXT: pushl $3
@ -34,53 +75,53 @@ entry:
; Again, we expect a sequence of 4 immediate pushes
; Checks that we generate the right pushes for >8bit immediates
; NORMAL-LABEL: test2b
; NORMAL-LABEL: test2b:
; NORMAL-NOT: subl {{.*}} %esp
; NORMAL: pushl $4096
; NORMAL-NEXT: pushl $3072
; NORMAL-NEXT: pushl $2048
; NORMAL-NEXT: pushl $1024
; NORMAL-NEXT: call
define void @test2b(i32 %k) {
; NORMAL-NEXT: addl $16, %esp
define void @test2b() optsize {
entry:
%a = alloca i32, i32 %k
call void @good(i32 1024, i32 2048, i32 3072, i32 4096)
ret void
}
; The first push should push a register
; NORMAL-LABEL: test3
; NORMAL-LABEL: test3:
; NORMAL-NOT: subl {{.*}} %esp
; NORMAL: pushl $4
; NORMAL-NEXT: pushl $3
; NORMAL-NEXT: pushl $2
; NORMAL-NEXT: pushl %e{{..}}
; NORMAL-NEXT: call
define void @test3(i32 %k) {
; NORMAL-NEXT: addl $16, %esp
define void @test3(i32 %k) optsize {
entry:
%a = alloca i32, i32 %k
call void @good(i32 %k, i32 2, i32 3, i32 4)
ret void
}
; We don't support weird calling conventions
; NORMAL-LABEL: test4
; NORMAL-LABEL: test4:
; NORMAL: subl $12, %esp
; NORMAL-NEXT: movl $4, 8(%esp)
; NORMAL-NEXT: movl $3, 4(%esp)
; NORMAL-NEXT: movl $1, (%esp)
; NORMAL-NEXT: movl $2, %eax
; NORMAL-NEXT: call
define void @test4(i32 %k) {
; NORMAL-NEXT: addl $12, %esp
define void @test4() optsize {
entry:
%a = alloca i32, i32 %k
call void @inreg(i32 1, i32 2, i32 3, i32 4)
ret void
}
; Check that additional alignment is added when the pushes
; don't add up to the required alignment.
; ALIGNED-LABEL: test5
; When there is no reserved call frame, check that additional alignment
; is added when the pushes don't add up to the required alignment.
; ALIGNED-LABEL: test5:
; ALIGNED: subl $16, %esp
; ALIGNED-NEXT: pushl $4
; ALIGNED-NEXT: pushl $3
@ -97,7 +138,7 @@ entry:
; Check that pushing the addresses of globals (Or generally, things that
; aren't exactly immediates) isn't broken.
; Fixes PR21878.
; NORMAL-LABEL: test6
; NORMAL-LABEL: test6:
; NORMAL: pushl $_ext
; NORMAL-NEXT: call
declare void @f(i8*)
@ -110,3 +151,108 @@ bb:
alloca i32
ret void
}
; Check that we fold simple cases into the push
; NORMAL-LABEL: test7:
; NORMAL-NOT: subl {{.*}} %esp
; NORMAL: movl 4(%esp), [[EAX:%e..]]
; NORMAL-NEXT: pushl $4
; NORMAL-NEXT: pushl ([[EAX]])
; NORMAL-NEXT: pushl $2
; NORMAL-NEXT: pushl $1
; NORMAL-NEXT: call
; NORMAL-NEXT: addl $16, %esp
define void @test7(i32* %ptr) optsize {
entry:
%val = load i32* %ptr
call void @good(i32 1, i32 2, i32 %val, i32 4)
ret void
}
; But we don't want to fold stack-relative loads into the push,
; because the offset will be wrong
; NORMAL-LABEL: test8:
; NORMAL-NOT: subl {{.*}} %esp
; NORMAL: movl 4(%esp), [[EAX:%e..]]
; NORMAL-NEXT: pushl $4
; NORMAL-NEXT: pushl [[EAX]]
; NORMAL-NEXT: pushl $2
; NORMAL-NEXT: pushl $1
; NORMAL-NEXT: call
; NORMAL-NEXT: addl $16, %esp
define void @test8(i32* %ptr) optsize {
entry:
%val = ptrtoint i32* %ptr to i32
call void @good(i32 1, i32 2, i32 %val, i32 4)
ret void
}
; If one function is using push instructions, and the other isn't
; (because it has frame-index references), then we must resolve
; these references correctly.
; NORMAL-LABEL: test9:
; NORMAL-NOT: leal (%esp),
; NORMAL: pushl $4
; NORMAL-NEXT: pushl $3
; NORMAL-NEXT: pushl $2
; NORMAL-NEXT: pushl $1
; NORMAL-NEXT: call
; NORMAL-NEXT: addl $16, %esp
; NORMAL-NEXT: subl $16, %esp
; NORMAL-NEXT: leal 16(%esp), [[EAX:%e..]]
; NORMAL-NEXT: movl [[EAX]], 12(%esp)
; NORMAL-NEXT: movl $7, 8(%esp)
; NORMAL-NEXT: movl $6, 4(%esp)
; NORMAL-NEXT: movl $5, (%esp)
; NORMAL-NEXT: call
; NORMAL-NEXT: addl $16, %esp
define void @test9() optsize {
entry:
%p = alloca i32, align 4
call void @good(i32 1, i32 2, i32 3, i32 4)
%0 = ptrtoint i32* %p to i32
call void @good(i32 5, i32 6, i32 7, i32 %0)
ret void
}
; We can end up with an indirect call which gets reloaded on the spot.
; Make sure we reference the correct stack slot - we spill into (%esp)
; and reload from 16(%esp) due to the pushes.
; NORMAL-LABEL: test10:
; NORMAL: movl $_good, [[ALLOC:.*]]
; NORMAL-NEXT: movl [[ALLOC]], [[EAX:%e..]]
; NORMAL-NEXT: movl [[EAX]], (%esp) # 4-byte Spill
; NORMAL: nop
; NORMAL: pushl $4
; NORMAL-NEXT: pushl $3
; NORMAL-NEXT: pushl $2
; NORMAL-NEXT: pushl $1
; NORMAL-NEXT: calll *16(%esp)
; NORMAL-NEXT: addl $16, %esp
define void @test10() optsize {
%stack_fptr = alloca void (i32, i32, i32, i32)*
store void (i32, i32, i32, i32)* @good, void (i32, i32, i32, i32)** %stack_fptr
%good_ptr = load volatile void (i32, i32, i32, i32)** %stack_fptr
call void asm sideeffect "nop", "~{ax},~{bx},~{cx},~{dx},~{bp},~{si},~{di}"()
call void (i32, i32, i32, i32)* %good_ptr(i32 1, i32 2, i32 3, i32 4)
ret void
}
; We can't fold the load from the global into the push because of
; interference from the store
; NORMAL-LABEL: test11:
; NORMAL: movl _the_global, [[EAX:%e..]]
; NORMAL-NEXT: movl $42, _the_global
; NORMAL-NEXT: pushl $4
; NORMAL-NEXT: pushl $3
; NORMAL-NEXT: pushl $2
; NORMAL-NEXT: pushl [[EAX]]
; NORMAL-NEXT: call
; NORMAL-NEXT: addl $16, %esp
@the_global = external global i32
define void @test11() optsize {
%myload = load i32* @the_global
store i32 42, i32* @the_global
call void @good(i32 %myload, i32 2, i32 3, i32 4)
ret void
}