[llvm] r269828 - X86: Avoid using _chkstk when lowering WIN_ALLOCA instructions
Mike Aizatsky via llvm-commits
llvm-commits at lists.llvm.org
Tue May 17 13:53:34 PDT 2016
Hans,
It seems your change broke sanitizer-windows bot. Could you take a look?
http://lab.llvm.org:8011/builders/sanitizer-windows/builds/22232
http://lab.llvm.org:8011/builders/sanitizer-windows/builds/22232/steps/run%20tests/logs/stdio
On Tue, May 17, 2016 at 1:19 PM Hans Wennborg via llvm-commits <
llvm-commits at lists.llvm.org> wrote:
> Author: hans
> Date: Tue May 17 15:13:29 2016
> New Revision: 269828
>
> URL: http://llvm.org/viewvc/llvm-project?rev=269828&view=rev
> Log:
> X86: Avoid using _chkstk when lowering WIN_ALLOCA instructions
>
> This patch moves the expansion of WIN_ALLOCA pseudo-instructions
> into a separate pass that walks the CFG and lowers the instructions
> based on a conservative estimate of the offset between the stack
> pointer and the lowest accessed stack address.
>
> The goal is to reduce binary size and run-time costs by removing
> calls to _chkstk. While it doesn't fix all the code quality problems
> with inalloca calls, it's an incremental improvement for PR27076.
>
> Differential Revision: http://reviews.llvm.org/D20263
>
> Added:
> llvm/trunk/lib/Target/X86/X86WinAllocaExpander.cpp
> llvm/trunk/test/CodeGen/X86/win-alloca-expander.ll
> Modified:
> llvm/trunk/lib/Target/X86/CMakeLists.txt
> llvm/trunk/lib/Target/X86/X86.h
> llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
> llvm/trunk/lib/Target/X86/X86ISelLowering.h
> llvm/trunk/lib/Target/X86/X86InstrCompiler.td
> llvm/trunk/lib/Target/X86/X86InstrInfo.td
> llvm/trunk/lib/Target/X86/X86MachineFunctionInfo.h
> llvm/trunk/lib/Target/X86/X86TargetMachine.cpp
> llvm/trunk/test/CodeGen/X86/cleanuppad-inalloca.ll
> llvm/trunk/test/CodeGen/X86/dynamic-alloca-in-entry.ll
> llvm/trunk/test/CodeGen/X86/inalloca-ctor.ll
> llvm/trunk/test/CodeGen/X86/inalloca-invoke.ll
> llvm/trunk/test/CodeGen/X86/inalloca-stdcall.ll
> llvm/trunk/test/CodeGen/X86/inalloca.ll
> llvm/trunk/test/CodeGen/X86/shrink-wrap-chkstk.ll
>
> Modified: llvm/trunk/lib/Target/X86/CMakeLists.txt
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/CMakeLists.txt?rev=269828&r1=269827&r2=269828&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/Target/X86/CMakeLists.txt (original)
> +++ llvm/trunk/lib/Target/X86/CMakeLists.txt Tue May 17 15:13:29 2016
> @@ -37,6 +37,7 @@ set(sources
> X86WinEHState.cpp
> X86OptimizeLEAs.cpp
> X86FixupBWInsts.cpp
> + X86WinAllocaExpander.cpp
> )
>
> add_llvm_target(X86CodeGen ${sources})
>
> Modified: llvm/trunk/lib/Target/X86/X86.h
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86.h?rev=269828&r1=269827&r2=269828&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/Target/X86/X86.h (original)
> +++ llvm/trunk/lib/Target/X86/X86.h Tue May 17 15:13:29 2016
> @@ -59,6 +59,9 @@ FunctionPass *createX86FixupLEAs();
> /// recalculations.
> FunctionPass *createX86OptimizeLEAs();
>
> +/// Return a pass that expands WinAlloca pseudo-instructions.
> +FunctionPass *createX86WinAllocaExpander();
> +
> /// Return a pass that optimizes the code-size of x86 call sequences.
> This is
> /// done by replacing esp-relative movs with pushes.
> FunctionPass *createX86CallFrameOptimization();
>
> Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=269828&r1=269827&r2=269828&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
> +++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Tue May 17 15:13:29 2016
> @@ -16563,14 +16563,9 @@ X86TargetLowering::LowerDYNAMIC_STACKALL
> Result = DAG.getNode(X86ISD::SEG_ALLOCA, dl, SPTy, Chain,
> DAG.getRegister(Vreg, SPTy));
> } else {
> - SDValue Flag;
> - const unsigned Reg = (Subtarget.isTarget64BitLP64() ? X86::RAX :
> X86::EAX);
> -
> - Chain = DAG.getCopyToReg(Chain, dl, Reg, Size, Flag);
> - Flag = Chain.getValue(1);
> SDVTList NodeTys = DAG.getVTList(MVT::Other, MVT::Glue);
> -
> - Chain = DAG.getNode(X86ISD::WIN_ALLOCA, dl, NodeTys, Chain, Flag);
> + Chain = DAG.getNode(X86ISD::WIN_ALLOCA, dl, NodeTys, Chain, Size);
> + MF.getInfo<X86MachineFunctionInfo>()->setHasWinAlloca(true);
>
> const X86RegisterInfo *RegInfo = Subtarget.getRegisterInfo();
> unsigned SPReg = RegInfo->getStackRegister();
> @@ -23228,18 +23223,6 @@ X86TargetLowering::EmitLoweredSegAlloca(
> }
>
> MachineBasicBlock *
> -X86TargetLowering::EmitLoweredWinAlloca(MachineInstr *MI,
> - MachineBasicBlock *BB) const {
> - assert(!Subtarget.isTargetMachO());
> - DebugLoc DL = MI->getDebugLoc();
> - MachineInstr *ResumeMI = Subtarget.getFrameLowering()->emitStackProbe(
> - *BB->getParent(), *BB, MI, DL, false);
> - MachineBasicBlock *ResumeBB = ResumeMI->getParent();
> - MI->eraseFromParent(); // The pseudo instruction is gone now.
> - return ResumeBB;
> -}
> -
> -MachineBasicBlock *
> X86TargetLowering::EmitLoweredCatchRet(MachineInstr *MI,
> MachineBasicBlock *BB) const {
> MachineFunction *MF = BB->getParent();
> @@ -23701,8 +23684,6 @@ X86TargetLowering::EmitInstrWithCustomIn
> case X86::TLS_base_addr32:
> case X86::TLS_base_addr64:
> return EmitLoweredTLSAddr(MI, BB);
> - case X86::WIN_ALLOCA:
> - return EmitLoweredWinAlloca(MI, BB);
> case X86::CATCHRET:
> return EmitLoweredCatchRet(MI, BB);
> case X86::CATCHPAD:
>
> Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.h
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.h?rev=269828&r1=269827&r2=269828&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/Target/X86/X86ISelLowering.h (original)
> +++ llvm/trunk/lib/Target/X86/X86ISelLowering.h Tue May 17 15:13:29 2016
> @@ -1162,9 +1162,6 @@ namespace llvm {
> MachineBasicBlock *EmitLoweredAtomicFP(MachineInstr *I,
> MachineBasicBlock *BB) const;
>
> - MachineBasicBlock *EmitLoweredWinAlloca(MachineInstr *MI,
> - MachineBasicBlock *BB)
> const;
> -
> MachineBasicBlock *EmitLoweredCatchRet(MachineInstr *MI,
> MachineBasicBlock *BB) const;
>
>
> Modified: llvm/trunk/lib/Target/X86/X86InstrCompiler.td
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86InstrCompiler.td?rev=269828&r1=269827&r2=269828&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/Target/X86/X86InstrCompiler.td (original)
> +++ llvm/trunk/lib/Target/X86/X86InstrCompiler.td Tue May 17 15:13:29 2016
> @@ -99,18 +99,6 @@ def VAARG_64 : I<0, Pseudo,
> (X86vaarg64 addr:$ap, imm:$size, imm:$mode,
> imm:$align)),
> (implicit EFLAGS)]>;
>
> -// Dynamic stack allocation yields a _chkstk or _alloca call for all
> Windows
> -// targets. These calls are needed to probe the stack when allocating
> more than
> -// 4k bytes in one go. Touching the stack at 4K increments is necessary to
> -// ensure that the guard pages used by the OS virtual memory manager are
> -// allocated in correct sequence.
> -// The main point of having separate instruction are extra unmodelled
> effects
> -// (compared to ordinary calls) like stack pointer change.
> -
> -let Defs = [EAX, ESP, EFLAGS], Uses = [ESP] in
> - def WIN_ALLOCA : I<0, Pseudo, (outs), (ins),
> - "# dynamic stack allocation",
> - [(X86WinAlloca)]>;
>
> // When using segmented stacks these are lowered into instructions which
> first
> // check if the current stacklet has enough free memory. If it does,
> memory is
> @@ -132,6 +120,27 @@ def SEG_ALLOCA_64 : I<0, Pseudo, (outs G
> Requires<[In64BitMode]>;
> }
>
> +// Dynamic stack allocation yields a _chkstk or _alloca call for all
> Windows
> +// targets. These calls are needed to probe the stack when allocating
> more than
> +// 4k bytes in one go. Touching the stack at 4K increments is necessary to
> +// ensure that the guard pages used by the OS virtual memory manager are
> +// allocated in correct sequence.
> +// The main point of having separate instruction are extra unmodelled
> effects
> +// (compared to ordinary calls) like stack pointer change.
> +
> +let Defs = [EAX, ESP, EFLAGS], Uses = [ESP] in
> +def WIN_ALLOCA_32 : I<0, Pseudo, (outs), (ins GR32:$size),
> + "# dynamic stack allocation",
> + [(X86WinAlloca GR32:$size)]>,
> + Requires<[NotLP64]>;
> +
> +let Defs = [RAX, RSP, EFLAGS], Uses = [RSP] in
> +def WIN_ALLOCA_64 : I<0, Pseudo, (outs), (ins GR64:$size),
> + "# dynamic stack allocation",
> + [(X86WinAlloca GR64:$size)]>,
> + Requires<[In64BitMode]>;
> +
> +
>
> //===----------------------------------------------------------------------===//
> // EH Pseudo Instructions
> //
>
> Modified: llvm/trunk/lib/Target/X86/X86InstrInfo.td
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86InstrInfo.td?rev=269828&r1=269827&r2=269828&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/Target/X86/X86InstrInfo.td (original)
> +++ llvm/trunk/lib/Target/X86/X86InstrInfo.td Tue May 17 15:13:29 2016
> @@ -112,6 +112,8 @@ def SDT_X86TLSBASEADDR : SDTypeProfile<0
>
> def SDT_X86TLSCALL : SDTypeProfile<0, 1, [SDTCisInt<0>]>;
>
> +def SDT_X86WIN_ALLOCA : SDTypeProfile<0, 1, [SDTCisVT<0, iPTR>]>;
> +
> def SDT_X86SEG_ALLOCA : SDTypeProfile<1, 1, [SDTCisVT<0, iPTR>,
> SDTCisVT<1, iPTR>]>;
>
> def SDT_X86EHRET : SDTypeProfile<0, 1, [SDTCisInt<0>]>;
> @@ -273,8 +275,8 @@ def X86bextr : SDNode<"X86ISD::BEXTR",
>
> def X86mul_imm : SDNode<"X86ISD::MUL_IMM", SDTIntBinOp>;
>
> -def X86WinAlloca : SDNode<"X86ISD::WIN_ALLOCA", SDTX86Void,
> - [SDNPHasChain, SDNPInGlue, SDNPOutGlue]>;
> +def X86WinAlloca : SDNode<"X86ISD::WIN_ALLOCA", SDT_X86WIN_ALLOCA,
> + [SDNPHasChain, SDNPOutGlue]>;
>
> def X86SegAlloca : SDNode<"X86ISD::SEG_ALLOCA", SDT_X86SEG_ALLOCA,
> [SDNPHasChain]>;
>
> Modified: llvm/trunk/lib/Target/X86/X86MachineFunctionInfo.h
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86MachineFunctionInfo.h?rev=269828&r1=269827&r2=269828&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/Target/X86/X86MachineFunctionInfo.h (original)
> +++ llvm/trunk/lib/Target/X86/X86MachineFunctionInfo.h Tue May 17 15:13:29
> 2016
> @@ -98,6 +98,9 @@ class X86MachineFunctionInfo : public Ma
> /// True if this function uses the red zone.
> bool UsesRedZone = false;
>
> + /// True if this function has WIN_ALLOCA instructions.
> + bool HasWinAlloca = false;
> +
> private:
> /// ForwardedMustTailRegParms - A list of virtual and physical registers
> /// that must be forwarded to every musttail call.
> @@ -172,6 +175,9 @@ public:
>
> bool getUsesRedZone() const { return UsesRedZone; }
> void setUsesRedZone(bool V) { UsesRedZone = V; }
> +
> + bool hasWinAlloca() const { return HasWinAlloca; }
> + void setHasWinAlloca(bool v) { HasWinAlloca = v; }
> };
>
> } // End llvm namespace
>
> Modified: llvm/trunk/lib/Target/X86/X86TargetMachine.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86TargetMachine.cpp?rev=269828&r1=269827&r2=269828&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/Target/X86/X86TargetMachine.cpp (original)
> +++ llvm/trunk/lib/Target/X86/X86TargetMachine.cpp Tue May 17 15:13:29 2016
> @@ -266,6 +266,7 @@ void X86PassConfig::addPreRegAlloc() {
> addPass(createX86OptimizeLEAs());
>
> addPass(createX86CallFrameOptimization());
> + addPass(createX86WinAllocaExpander());
> }
>
> void X86PassConfig::addPostRegAlloc() {
>
> Added: llvm/trunk/lib/Target/X86/X86WinAllocaExpander.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86WinAllocaExpander.cpp?rev=269828&view=auto
>
> ==============================================================================
> --- llvm/trunk/lib/Target/X86/X86WinAllocaExpander.cpp (added)
> +++ llvm/trunk/lib/Target/X86/X86WinAllocaExpander.cpp Tue May 17 15:13:29
> 2016
> @@ -0,0 +1,294 @@
> +//===----- X86WinAllocaExpander.cpp - Expand WinAlloca pseudo instruction
> -===//
> +//
> +// 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 expands WinAlloca pseudo-instructions.
> +//
> +// It performs a conservative analysis to determine whether each
> allocation
> +// falls within a region of the stack that is safe to use, or whether
> stack
> +// probes must be emitted.
> +//
>
> +//===----------------------------------------------------------------------===//
> +
> +#include "X86.h"
> +#include "X86InstrBuilder.h"
> +#include "X86InstrInfo.h"
> +#include "X86MachineFunctionInfo.h"
> +#include "X86Subtarget.h"
> +#include "llvm/ADT/PostOrderIterator.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/raw_ostream.h"
> +#include "llvm/Target/TargetInstrInfo.h"
> +
> +using namespace llvm;
> +
> +namespace {
> +
> +class X86WinAllocaExpander : public MachineFunctionPass {
> +public:
> + X86WinAllocaExpander() : MachineFunctionPass(ID) {}
> +
> + bool runOnMachineFunction(MachineFunction &MF) override;
> +
> +private:
> + /// Strategies for lowering a WinAlloca.
> + enum Lowering { TouchAndSub, Sub, Probe };
> +
> + /// Deterministic-order map from WinAlloca instruction to desired
> lowering.
> + typedef MapVector<MachineInstr*, Lowering> LoweringMap;
> +
> + /// Compute which lowering to use for each WinAlloca instruction.
> + void computeLowerings(MachineFunction &MF, LoweringMap& Lowerings);
> +
> + /// Get the appropriate lowering based on current offset and amount.
> + Lowering getLowering(int64_t CurrentOffset, int64_t AllocaAmount);
> +
> + /// Lower a WinAlloca instruction.
> + void lower(MachineInstr* MI, Lowering L);
> +
> + MachineRegisterInfo *MRI;
> + const X86Subtarget *STI;
> + const TargetInstrInfo *TII;
> + const X86RegisterInfo *TRI;
> + unsigned StackPtr;
> + unsigned SlotSize;
> + int64_t StackProbeSize;
> +
> + const char *getPassName() const override { return "X86 WinAlloca
> Expander"; }
> + static char ID;
> +};
> +
> +char X86WinAllocaExpander::ID = 0;
> +
> +} // end anonymous namespace
> +
> +FunctionPass *llvm::createX86WinAllocaExpander() {
> + return new X86WinAllocaExpander();
> +}
> +
> +/// Return the allocation amount for a WinAlloca instruction, or -1 if
> unknown.
> +static int64_t getWinAllocaAmount(MachineInstr *MI, MachineRegisterInfo
> *MRI) {
> + assert(MI->getOpcode() == X86::WIN_ALLOCA_32 ||
> + MI->getOpcode() == X86::WIN_ALLOCA_64);
> + assert(MI->getOperand(0).isReg());
> +
> + unsigned AmountReg = MI->getOperand(0).getReg();
> + MachineInstr *Def = MRI->getUniqueVRegDef(AmountReg);
> +
> + // Look through copies.
> + while (Def && Def->isCopy() && Def->getOperand(1).isReg())
> + Def = MRI->getUniqueVRegDef(Def->getOperand(1).getReg());
> +
> + if (!Def ||
> + (Def->getOpcode() != X86::MOV32ri && Def->getOpcode() !=
> X86::MOV64ri) ||
> + !Def->getOperand(1).isImm())
> + return -1;
> +
> + return Def->getOperand(1).getImm();
> +}
> +
> +X86WinAllocaExpander::Lowering
> +X86WinAllocaExpander::getLowering(int64_t CurrentOffset,
> + int64_t AllocaAmount) {
> + // For a non-constant amount or a large amount, we have to probe.
> + if (AllocaAmount < 0 || AllocaAmount > StackProbeSize)
> + return Probe;
> +
> + // If it fits within the safe region of the stack, just subtract.
> + if (CurrentOffset + AllocaAmount <= StackProbeSize)
> + return Sub;
> +
> + // Otherwise, touch the current tip of the stack, then subtract.
> + return TouchAndSub;
> +}
> +
> +static bool isPushPop(const MachineInstr &MI) {
> + switch (MI.getOpcode()) {
> + case X86::PUSH32i8:
> + case X86::PUSH32r:
> + case X86::PUSH32rmm:
> + case X86::PUSH32rmr:
> + case X86::PUSHi32:
> + case X86::PUSH64i8:
> + case X86::PUSH64r:
> + case X86::PUSH64rmm:
> + case X86::PUSH64rmr:
> + case X86::PUSH64i32:
> + case X86::POP32r:
> + case X86::POP64r:
> + return true;
> + default:
> + return false;
> + }
> +}
> +
> +void X86WinAllocaExpander::computeLowerings(MachineFunction &MF,
> + LoweringMap &Lowerings) {
> + // Do a one-pass reverse post-order walk of the CFG to conservatively
> estimate
> + // the offset between the stack pointer and the lowest touched part of
> the
> + // stack, and use that to decide how to lower each WinAlloca
> instruction.
> +
> + // Initialize OutOffset[B], the stack offset at exit from B, to
> something big.
> + DenseMap<MachineBasicBlock *, int64_t> OutOffset;
> + for (MachineBasicBlock &MBB : MF)
> + OutOffset[&MBB] = INT32_MAX;
> +
> + // Note: we don't know the offset at the start of the entry block since
> the
> + // prologue hasn't been inserted yet, and how much that will adjust the
> stack
> + // pointer depends on register spills, which have not been computed yet.
> +
> + // Compute the reverse post-order.
> + ReversePostOrderTraversal<MachineFunction*> RPO(&MF);
> +
> + for (MachineBasicBlock *MBB : RPO) {
> + int64_t Offset = -1;
> + for (MachineBasicBlock *Pred : MBB->predecessors())
> + Offset = std::max(Offset, OutOffset[Pred]);
> + if (Offset == -1) Offset = INT32_MAX;
> +
> + for (MachineInstr &MI : *MBB) {
> + if (MI.getOpcode() == X86::WIN_ALLOCA_32 ||
> + MI.getOpcode() == X86::WIN_ALLOCA_64) {
> + // A WinAlloca moves StackPtr, and potentially touches it.
> + int64_t Amount = getWinAllocaAmount(&MI, MRI);
> + Lowering L = getLowering(Offset, Amount);
> + Lowerings[&MI] = L;
> + switch (L) {
> + case Sub:
> + Offset += Amount;
> + break;
> + case TouchAndSub:
> + Offset = Amount;
> + break;
> + case Probe:
> + Offset = 0;
> + break;
> + }
> + } else if (MI.isCall() || isPushPop(MI)) {
> + // Calls, pushes and pops touch the tip of the stack.
> + Offset = 0;
> + } else if (MI.getOpcode() == X86::ADJCALLSTACKUP32 ||
> + MI.getOpcode() == X86::ADJCALLSTACKUP64) {
> + Offset -= MI.getOperand(0).getImm();
> + } else if (MI.getOpcode() == X86::ADJCALLSTACKDOWN32 ||
> + MI.getOpcode() == X86::ADJCALLSTACKDOWN64) {
> + Offset += MI.getOperand(0).getImm();
> + } else if (MI.modifiesRegister(StackPtr, TRI)) {
> + // Any other modification of SP means we've lost track of it.
> + Offset = INT32_MAX;
> + }
> + }
> +
> + OutOffset[MBB] = Offset;
> + }
> +}
> +
> +static unsigned getSubOpcode(bool Is64Bit, int64_t Amount) {
> + if (Is64Bit)
> + return isInt<8>(Amount) ? X86::SUB64ri8 : X86::SUB64ri32;
> + return isInt<8>(Amount) ? X86::SUB32ri8 : X86::SUB32ri;
> +}
> +
> +void X86WinAllocaExpander::lower(MachineInstr* MI, Lowering L) {
> + DebugLoc DL = MI->getDebugLoc();
> + MachineBasicBlock *MBB = MI->getParent();
> + MachineBasicBlock::iterator I = *MI;
> +
> + int64_t Amount = getWinAllocaAmount(MI, MRI);
> + if (Amount == 0) {
> + MI->eraseFromParent();
> + return;
> + }
> +
> + bool Is64Bit = STI->is64Bit();
> + assert(SlotSize == 4 || SlotSize == 8);
> + unsigned RegA = (SlotSize == 8) ? X86::RAX : X86::EAX;
> +
> + switch (L) {
> + case TouchAndSub:
> + assert(Amount >= SlotSize);
> +
> + // Use a push to touch the top of the stack.
> + BuildMI(*MBB, I, DL, TII->get(Is64Bit ? X86::PUSH64r : X86::PUSH32r))
> + .addReg(RegA, RegState::Undef);
> + Amount -= SlotSize;
> + if (!Amount)
> + break;
> +
> + // Fall through to make any remaining adjustment.
> + case Sub:
> + assert(Amount > 0);
> + if (Amount == SlotSize) {
> + // Use push to save size.
> + BuildMI(*MBB, I, DL, TII->get(Is64Bit ? X86::PUSH64r :
> X86::PUSH32r))
> + .addReg(RegA, RegState::Undef);
> + } else {
> + // Sub.
> + BuildMI(*MBB, I, DL, TII->get(getSubOpcode(Is64Bit, Amount)),
> StackPtr)
> + .addReg(StackPtr)
> + .addImm(Amount);
> + }
> + break;
> + case Probe:
> + // The probe lowering expects the amount in RAX/EAX.
> + BuildMI(*MBB, MI, DL, TII->get(TargetOpcode::COPY), RegA)
> + .addReg(MI->getOperand(0).getReg());
> +
> + // Do the probe.
> + STI->getFrameLowering()->emitStackProbe(*MBB->getParent(), *MBB, MI,
> DL,
> + /*InPrologue=*/false);
> + break;
> + }
> +
> + unsigned AmountReg = MI->getOperand(0).getReg();
> + MI->eraseFromParent();
> +
> + // Delete the definition of AmountReg, possibly walking a chain of
> copies.
> + for (;;) {
> + if (!MRI->use_empty(AmountReg))
> + break;
> + MachineInstr *AmountDef = MRI->getUniqueVRegDef(AmountReg);
> + if (!AmountDef)
> + break;
> + if (AmountDef->isCopy() && AmountDef->getOperand(1).isReg())
> + AmountReg = AmountDef->getOperand(1).isReg();
> + AmountDef->eraseFromParent();
> + break;
> + }
> +}
> +
> +bool X86WinAllocaExpander::runOnMachineFunction(MachineFunction &MF) {
> + if (!MF.getInfo<X86MachineFunctionInfo>()->hasWinAlloca())
> + return false;
> +
> + MRI = &MF.getRegInfo();
> + STI = &MF.getSubtarget<X86Subtarget>();
> + TII = STI->getInstrInfo();
> + TRI = STI->getRegisterInfo();
> + StackPtr = TRI->getStackRegister();
> + SlotSize = TRI->getSlotSize();
> +
> + StackProbeSize = 4096;
> + if (MF.getFunction()->hasFnAttribute("stack-probe-size")) {
> + MF.getFunction()
> + ->getFnAttribute("stack-probe-size")
> + .getValueAsString()
> + .getAsInteger(0, StackProbeSize);
> + }
> +
> + LoweringMap Lowerings;
> + computeLowerings(MF, Lowerings);
> + for (auto &P : Lowerings)
> + lower(P.first, P.second);
> +
> + return true;
> +}
>
> Modified: llvm/trunk/test/CodeGen/X86/cleanuppad-inalloca.ll
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/cleanuppad-inalloca.ll?rev=269828&r1=269827&r2=269828&view=diff
>
> ==============================================================================
> --- llvm/trunk/test/CodeGen/X86/cleanuppad-inalloca.ll (original)
> +++ llvm/trunk/test/CodeGen/X86/cleanuppad-inalloca.ll Tue May 17 15:13:29
> 2016
> @@ -38,8 +38,8 @@ ehcleanup:
> ; CHECK: pushl %ebp
> ; CHECK: movl %esp, %ebp
> ; CHECK: subl ${{[0-9]+}}, %esp
> -; CHECK: movl $8, %eax
> -; CHECK: calll __chkstk
> +; CHECK: pushl %eax
> +; CHECK: pushl %eax
> ; CHECK: calll "??0A@@QAE at XZ"
> ; CHECK: calll "??0A@@QAE at XZ"
> ; CHECK: calll _takes_two
>
> Modified: llvm/trunk/test/CodeGen/X86/dynamic-alloca-in-entry.ll
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/dynamic-alloca-in-entry.ll?rev=269828&r1=269827&r2=269828&view=diff
>
> ==============================================================================
> --- llvm/trunk/test/CodeGen/X86/dynamic-alloca-in-entry.ll (original)
> +++ llvm/trunk/test/CodeGen/X86/dynamic-alloca-in-entry.ll Tue May 17
> 15:13:29 2016
> @@ -15,5 +15,5 @@ define void @bar() {
> ret void
> }
> ; CHECK-LABEL: _bar:
> -; CHECK: calll __chkstk
> +; CHECK: pushl %eax
> ; CHECK: retl
>
> Modified: llvm/trunk/test/CodeGen/X86/inalloca-ctor.ll
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/inalloca-ctor.ll?rev=269828&r1=269827&r2=269828&view=diff
>
> ==============================================================================
> --- llvm/trunk/test/CodeGen/X86/inalloca-ctor.ll (original)
> +++ llvm/trunk/test/CodeGen/X86/inalloca-ctor.ll Tue May 17 15:13:29 2016
> @@ -12,8 +12,8 @@ define void @g() {
> entry:
> %args = alloca inalloca %frame
> %c = getelementptr %frame, %frame* %args, i32 0, i32 2
> -; CHECK: movl $20, %eax
> -; CHECK: calll __chkstk
> +; CHECK: pushl %eax
> +; CHECK: subl $16, %esp
> ; CHECK: movl %esp,
> call void @Foo_ctor(%Foo* %c)
> ; CHECK: leal 12(%{{.*}}),
>
> Modified: llvm/trunk/test/CodeGen/X86/inalloca-invoke.ll
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/inalloca-invoke.ll?rev=269828&r1=269827&r2=269828&view=diff
>
> ==============================================================================
> --- llvm/trunk/test/CodeGen/X86/inalloca-invoke.ll (original)
> +++ llvm/trunk/test/CodeGen/X86/inalloca-invoke.ll Tue May 17 15:13:29 2016
> @@ -21,7 +21,8 @@ blah:
> %beg = getelementptr %frame.reverse, %frame.reverse* %rev_args, i32 0,
> i32 0
> %end = getelementptr %frame.reverse, %frame.reverse* %rev_args, i32 0,
> i32 1
>
> -; CHECK: calll __chkstk
> +; CHECK: pushl %eax
> +; CHECK: subl $20, %esp
> ; CHECK: movl %esp, %[[beg:[^ ]*]]
> ; CHECK: leal 12(%[[beg]]), %[[end:[^ ]*]]
>
>
> Modified: llvm/trunk/test/CodeGen/X86/inalloca-stdcall.ll
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/inalloca-stdcall.ll?rev=269828&r1=269827&r2=269828&view=diff
>
> ==============================================================================
> --- llvm/trunk/test/CodeGen/X86/inalloca-stdcall.ll (original)
> +++ llvm/trunk/test/CodeGen/X86/inalloca-stdcall.ll Tue May 17 15:13:29
> 2016
> @@ -8,8 +8,8 @@ declare x86_stdcallcc void @i(i32 %a)
> define void @g() {
> ; CHECK-LABEL: _g:
> %b = alloca inalloca %Foo
> -; CHECK: movl $8, %eax
> -; CHECK: calll __chkstk
> +; CHECK: pushl %eax
> +; CHECK: pushl %eax
> %f1 = getelementptr %Foo, %Foo* %b, i32 0, i32 0
> %f2 = getelementptr %Foo, %Foo* %b, i32 0, i32 1
> store i32 13, i32* %f1
>
> Modified: llvm/trunk/test/CodeGen/X86/inalloca.ll
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/inalloca.ll?rev=269828&r1=269827&r2=269828&view=diff
>
> ==============================================================================
> --- llvm/trunk/test/CodeGen/X86/inalloca.ll (original)
> +++ llvm/trunk/test/CodeGen/X86/inalloca.ll Tue May 17 15:13:29 2016
> @@ -8,8 +8,8 @@ define void @a() {
> ; CHECK-LABEL: _a:
> entry:
> %b = alloca inalloca %Foo
> -; CHECK: movl $8, %eax
> -; CHECK: calll __chkstk
> +; CHECK: pushl %eax
> +; CHECK: pushl %eax
> %f1 = getelementptr %Foo, %Foo* %b, i32 0, i32 0
> %f2 = getelementptr %Foo, %Foo* %b, i32 0, i32 1
> store i32 13, i32* %f1
> @@ -28,8 +28,8 @@ define void @b() {
> ; CHECK-LABEL: _b:
> entry:
> %b = alloca inalloca %Foo
> -; CHECK: movl $8, %eax
> -; CHECK: calll __chkstk
> +; CHECK: pushl %eax
> +; CHECK: pushl %eax
> %f1 = getelementptr %Foo, %Foo* %b, i32 0, i32 0
> %f2 = getelementptr %Foo, %Foo* %b, i32 0, i32 1
> store i32 13, i32* %f1
> @@ -49,8 +49,8 @@ define void @c() {
> ; CHECK-LABEL: _c:
> entry:
> %b = alloca inalloca %Foo
> -; CHECK: movl $8, %eax
> -; CHECK: calll __chkstk
> +; CHECK: pushl %eax
> +; CHECK: pushl %eax
> %f1 = getelementptr %Foo, %Foo* %b, i32 0, i32 0
> %f2 = getelementptr %Foo, %Foo* %b, i32 0, i32 1
> store i32 13, i32* %f1
>
> Modified: llvm/trunk/test/CodeGen/X86/shrink-wrap-chkstk.ll
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/shrink-wrap-chkstk.ll?rev=269828&r1=269827&r2=269828&view=diff
>
> ==============================================================================
> --- llvm/trunk/test/CodeGen/X86/shrink-wrap-chkstk.ll (original)
> +++ llvm/trunk/test/CodeGen/X86/shrink-wrap-chkstk.ll Tue May 17 15:13:29
> 2016
> @@ -7,7 +7,7 @@
> target datalayout = "e-m:x-p:32:32-i64:64-f80:32-n8:16:32-a:0:32-S32"
> target triple = "i686-pc-windows-msvc18.0.0"
>
> -%struct.S = type { [12 x i8] }
> +%struct.S = type { [8192 x i8] }
>
> define x86_thiscallcc void @call_inalloca(i1 %x) {
> entry:
> @@ -29,7 +29,7 @@ bb2:
> ; CHECK-LABEL: _call_inalloca: # @call_inalloca
> ; CHECK: pushl %ebp
> ; CHECK: movl %esp, %ebp
> -; CHECK: movl $12, %eax
> +; CHECK: movl $8192, %eax
> ; CHECK: calll __chkstk
> ; CHECK: calll _inalloca_params
> ; CHECK: movl %ebp, %esp
>
> Added: llvm/trunk/test/CodeGen/X86/win-alloca-expander.ll
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/win-alloca-expander.ll?rev=269828&view=auto
>
> ==============================================================================
> --- llvm/trunk/test/CodeGen/X86/win-alloca-expander.ll (added)
> +++ llvm/trunk/test/CodeGen/X86/win-alloca-expander.ll Tue May 17 15:13:29
> 2016
> @@ -0,0 +1,153 @@
> +; RUN: llc < %s -mtriple=i686-pc-win32 | FileCheck %s
> +
> +%struct.S = type { [1024 x i8] }
> +%struct.T = type { [3000 x i8] }
> +%struct.U = type { [10000 x i8] }
> +
> +define void @basics() {
> +; CHECK-LABEL: basics:
> +entry:
> + br label %bb1
> +
> +; Allocation move sizes should have been removed.
> +; CHECK-NOT: movl $1024
> +; CHECK-NOT: movl $3000
> +
> +bb1:
> + %p0 = alloca %struct.S
> +; The allocation is small enough not to require stack probing, but the
> %esp
> +; offset after the prologue is not known, so the stack must be touched
> before
> +; the pointer is adjusted.
> +; CHECK: pushl %eax
> +; CHECK: subl $1020, %esp
> +
> + %saved_stack = tail call i8* @llvm.stacksave()
> +
> + %p1 = alloca %struct.S
> +; We know the %esp offset from above, so there is no need to touch the
> stack
> +; before adjusting it.
> +; CHECK: subl $1024, %esp
> +
> + %p2 = alloca %struct.T
> +; The offset is now 2048 bytes, so allocating a T must touch the stack
> again.
> +; CHECK: pushl %eax
> +; CHECK: subl $2996, %esp
> +
> + call void @f(%struct.S* %p0)
> +; CHECK: calll
> +
> + %p3 = alloca %struct.T
> +; The call above touched the stack, so there is room for a T object.
> +; CHECK: subl $3000, %esp
> +
> + %p4 = alloca %struct.U
> +; The U object is large enough to require stack probing.
> +; CHECK: movl $10000, %eax
> +; CHECK: calll __chkstk
> +
> + %p5 = alloca %struct.T
> +; The stack probing above touched the tip of the stack, so there's room
> for a T.
> +; CHECK: subl $3000, %esp
> +
> + call void @llvm.stackrestore(i8* %saved_stack)
> + %p6 = alloca %struct.S
> +; The stack restore means we lose track of the stack pointer and must
> probe.
> +; CHECK: pushl %eax
> +; CHECK: subl $1020, %esp
> +
> +; Use the pointers so they're not optimized away.
> + call void @f(%struct.S* %p1)
> + call void @g(%struct.T* %p2)
> + call void @g(%struct.T* %p3)
> + call void @h(%struct.U* %p4)
> + call void @g(%struct.T* %p5)
> + ret void
> +}
> +
> +define void @loop() {
> +; CHECK-LABEL: loop:
> +entry:
> + br label %bb1
> +
> +bb1:
> + %p1 = alloca %struct.S
> +; The entry offset is unknown; touch-and-sub.
> +; CHECK: pushl %eax
> +; CHECK: subl $1020, %esp
> + br label %loop1
> +
> +loop1:
> + %i1 = phi i32 [ 10, %bb1 ], [ %dec1, %loop1 ]
> + %p2 = alloca %struct.S
> +; We know the incoming offset from bb1, but from the back-edge, we assume
> the
> +; worst, and therefore touch-and-sub to allocate.
> +; CHECK: pushl %eax
> +; CHECK: subl $1020, %esp
> + %dec1 = sub i32 %i1, 1
> + %cmp1 = icmp sgt i32 %i1, 0
> + br i1 %cmp1, label %loop1, label %end
> +; CHECK: decl
> +; CHECK: jg
> +
> +end:
> + call void @f(%struct.S* %p1)
> + call void @f(%struct.S* %p2)
> + ret void
> +}
> +
> +define void @probe_size_attribute() "stack-probe-size"="512" {
> +; CHECK-LABEL: probe_size_attribute:
> +entry:
> + br label %bb1
> +
> +bb1:
> + %p0 = alloca %struct.S
> +; The allocation would be small enough not to require probing, if it
> wasn't
> +; for the stack-probe-size attribute.
> +; CHECK: movl $1024, %eax
> +; CHECK: calll __chkstk
> + call void @f(%struct.S* %p0)
> + ret void
> +}
> +
> +define void @cfg(i1 %x, i1 %y) {
> +; Test that the blocks are analyzed in the correct order.
> +; CHECK-LABEL: cfg:
> +entry:
> + br i1 %x, label %bb1, label %bb2
> +
> +bb1:
> + %p1 = alloca %struct.S
> +; CHECK: pushl %eax
> +; CHECK: subl $1020, %esp
> + br label %bb3
> +bb2:
> + %p2 = alloca %struct.T
> +; CHECK: pushl %eax
> +; CHECK: subl $2996, %esp
> + br label %bb3
> +
> +bb3:
> + br i1 %y, label %bb4, label %bb5
> +
> +bb4:
> + %p4 = alloca %struct.S
> +; CHECK: subl $1024, %esp
> + call void @f(%struct.S* %p4)
> + ret void
> +
> +bb5:
> + %p5 = alloca %struct.T
> +; CHECK: pushl %eax
> +; CHECK: subl $2996, %esp
> + call void @g(%struct.T* %p5)
> + ret void
> +}
> +
> +
> +declare void @f(%struct.S*)
> +declare void @g(%struct.T*)
> +declare void @h(%struct.U*)
> +
> +declare i8* @llvm.stacksave()
> +declare void @llvm.stackrestore(i8*)
>
>
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>
--
Mike
Sent from phone
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