[llvm] r269756 - [WebAssembly] Remove our copy of PrologEpilogInserter
Derek Schuff via llvm-commits
llvm-commits at lists.llvm.org
Tue May 17 04:18:35 PDT 2016
Author: dschuff
Date: Tue May 17 06:18:35 2016
New Revision: 269756
URL: http://llvm.org/viewvc/llvm-project?rev=269756&view=rev
Log:
[WebAssembly] Remove our copy of PrologEpilogInserter
It's no longer needed after r269750
Removed:
llvm/trunk/lib/Target/WebAssembly/WebAssemblyPEI.cpp
Modified:
llvm/trunk/lib/Target/WebAssembly/CMakeLists.txt
llvm/trunk/lib/Target/WebAssembly/WebAssembly.h
Modified: llvm/trunk/lib/Target/WebAssembly/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/WebAssembly/CMakeLists.txt?rev=269756&r1=269755&r2=269756&view=diff
==============================================================================
--- llvm/trunk/lib/Target/WebAssembly/CMakeLists.txt (original)
+++ llvm/trunk/lib/Target/WebAssembly/CMakeLists.txt Tue May 17 06:18:35 2016
@@ -25,7 +25,6 @@ add_llvm_target(WebAssemblyCodeGen
WebAssemblyOptimizeLiveIntervals.cpp
WebAssemblyOptimizeReturned.cpp
WebAssemblyPeephole.cpp
- WebAssemblyPEI.cpp
WebAssemblyPrepareForLiveIntervals.cpp
WebAssemblyRegisterInfo.cpp
WebAssemblyRegColoring.cpp
Modified: llvm/trunk/lib/Target/WebAssembly/WebAssembly.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/WebAssembly/WebAssembly.h?rev=269756&r1=269755&r2=269756&view=diff
==============================================================================
--- llvm/trunk/lib/Target/WebAssembly/WebAssembly.h (original)
+++ llvm/trunk/lib/Target/WebAssembly/WebAssembly.h Tue May 17 06:18:35 2016
@@ -32,9 +32,6 @@ FunctionPass *createWebAssemblyISelDag(W
FunctionPass *createWebAssemblyArgumentMove();
FunctionPass *createWebAssemblySetP2AlignOperands();
-// Regalloc-time passes.
-FunctionPass *createWebAssemblyPEI();
-
// Late passes.
FunctionPass *createWebAssemblyReplacePhysRegs();
FunctionPass *createWebAssemblyPrepareForLiveIntervals();
Removed: llvm/trunk/lib/Target/WebAssembly/WebAssemblyPEI.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/WebAssembly/WebAssemblyPEI.cpp?rev=269755&view=auto
==============================================================================
--- llvm/trunk/lib/Target/WebAssembly/WebAssemblyPEI.cpp (original)
+++ llvm/trunk/lib/Target/WebAssembly/WebAssemblyPEI.cpp (removed)
@@ -1,1056 +0,0 @@
-//===-- WebAssemblyPEI.cpp - Insert Prolog/Epilog code in function --===//
-//
-// The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This pass is responsible for finalizing the functions frame layout, saving
-// callee saved registers, and for emitting prolog & epilog code for the
-// function.
-//
-// This pass must be run after register allocation. After this pass is
-// executed, it is illegal to construct MO_FrameIndex operands.
-//
-// This is a copy of lib/CodeGen/PrologEpilogInserter.cpp except that it does
-// not assert that all virtual registers are gone (because WebAssembly currently
-// uses virtual rather than physical registers), and only runs
-// MRI.clearVirtRegs() if scavenging happened (which it never does). It also
-// uses a different class name so it can be registered via INITIALIZE_PASS.
-// It is otherwise unmodified, so any changes to the target-independent PEI
-// can be easily applied.
-//===----------------------------------------------------------------------===//
-
-#include "llvm/ADT/STLExtras.h"
-#include "llvm/ADT/SetVector.h"
-#include "llvm/ADT/SmallSet.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/CodeGen/MachineDominators.h"
-#include "llvm/CodeGen/MachineFrameInfo.h"
-#include "llvm/CodeGen/MachineInstr.h"
-#include "llvm/CodeGen/MachineLoopInfo.h"
-#include "llvm/CodeGen/MachineModuleInfo.h"
-#include "llvm/CodeGen/MachineRegisterInfo.h"
-#include "llvm/CodeGen/Passes.h"
-#include "llvm/CodeGen/RegisterScavenging.h"
-#include "llvm/CodeGen/StackProtector.h"
-#include "llvm/CodeGen/TargetPassConfig.h"
-#include "llvm/CodeGen/WinEHFuncInfo.h"
-#include "llvm/IR/DiagnosticInfo.h"
-#include "llvm/IR/InlineAsm.h"
-#include "llvm/IR/LLVMContext.h"
-#include "llvm/Support/CommandLine.h"
-#include "llvm/Support/Debug.h"
-#include "llvm/Support/raw_ostream.h"
-#include "llvm/Target/TargetFrameLowering.h"
-#include "llvm/Target/TargetInstrInfo.h"
-#include "llvm/Target/TargetMachine.h"
-#include "llvm/Target/TargetRegisterInfo.h"
-#include "llvm/Target/TargetSubtargetInfo.h"
-#include <climits>
-
-using namespace llvm;
-
-#define DEBUG_TYPE "pei"
-namespace llvm {
-void initializeWasmPEIPass(PassRegistry&);
-}
-namespace {
-class WasmPEI final : public MachineFunctionPass {
-public:
- static char ID;
- WasmPEI() : MachineFunctionPass(ID) {
- initializeWasmPEIPass(*PassRegistry::getPassRegistry());
- }
-
- void getAnalysisUsage(AnalysisUsage &AU) const override;
-
- /// runOnMachineFunction - Insert prolog/epilog code and replace abstract
- /// frame indexes with appropriate references.
- ///
- bool runOnMachineFunction(MachineFunction &Fn) override;
-
-private:
- RegScavenger *RS;
-
- // MinCSFrameIndex, MaxCSFrameIndex - Keeps the range of callee saved
- // stack frame indexes.
- unsigned MinCSFrameIndex, MaxCSFrameIndex;
-
- // Save and Restore blocks of the current function. Typically there is a
- // single save block, unless Windows EH funclets are involved.
- SmallVector<MachineBasicBlock *, 1> SaveBlocks;
- SmallVector<MachineBasicBlock *, 4> RestoreBlocks;
-
- // Flag to control whether to use the register scavenger to resolve
- // frame index materialization registers. Set according to
- // TRI->requiresFrameIndexScavenging() for the current function.
- bool FrameIndexVirtualScavenging;
-
- void calculateSets(MachineFunction &Fn);
- void calculateCallsInformation(MachineFunction &Fn);
- void assignCalleeSavedSpillSlots(MachineFunction &Fn,
- const BitVector &SavedRegs);
- void insertCSRSpillsAndRestores(MachineFunction &Fn);
- void calculateFrameObjectOffsets(MachineFunction &Fn);
- void replaceFrameIndices(MachineFunction &Fn);
- void replaceFrameIndices(MachineBasicBlock *BB, MachineFunction &Fn,
- int &SPAdj);
- void scavengeFrameVirtualRegs(MachineFunction &Fn);
- void insertPrologEpilogCode(MachineFunction &Fn);
-};
-} // namespace
-
-char WasmPEI::ID = 0;
-
-namespace llvm {
-FunctionPass *createWebAssemblyPEI() {
- return new WasmPEI();
-}
-}
-
-static cl::opt<unsigned>
-WarnStackSize("wasm-warn-stack-size", cl::Hidden, cl::init((unsigned)-1),
- cl::desc("Warn for stack size bigger than the given"
- " number"));
-
-INITIALIZE_PASS_BEGIN(WasmPEI, "wasmprologepilog",
- "Wasm Prologue/Epilogue Insertion", false, false)
-INITIALIZE_PASS_DEPENDENCY(MachineLoopInfo)
-INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree)
-INITIALIZE_PASS_DEPENDENCY(StackProtector)
-INITIALIZE_PASS_DEPENDENCY(TargetPassConfig)
-INITIALIZE_PASS_END(WasmPEI, "wasmprologepilog",
- "Wasm Prologue/Epilogue Insertion & Frame Finalization",
- false, false)
-
-STATISTIC(NumScavengedRegs, "Number of frame index regs scavenged");
-STATISTIC(NumBytesStackSpace,
- "Number of bytes used for stack in all functions");
-
-void WasmPEI::getAnalysisUsage(AnalysisUsage &AU) const {
- AU.setPreservesCFG();
- AU.addPreserved<MachineLoopInfo>();
- AU.addPreserved<MachineDominatorTree>();
- AU.addRequired<StackProtector>();
- AU.addRequired<TargetPassConfig>();
- MachineFunctionPass::getAnalysisUsage(AU);
-}
-
-/// Compute the set of return blocks
-void WasmPEI::calculateSets(MachineFunction &Fn) {
- const MachineFrameInfo *MFI = Fn.getFrameInfo();
-
- // Even when we do not change any CSR, we still want to insert the
- // prologue and epilogue of the function.
- // So set the save points for those.
-
- // Use the points found by shrink-wrapping, if any.
- if (MFI->getSavePoint()) {
- SaveBlocks.push_back(MFI->getSavePoint());
- assert(MFI->getRestorePoint() && "Both restore and save must be set");
- MachineBasicBlock *RestoreBlock = MFI->getRestorePoint();
- // If RestoreBlock does not have any successor and is not a return block
- // then the end point is unreachable and we do not need to insert any
- // epilogue.
- if (!RestoreBlock->succ_empty() || RestoreBlock->isReturnBlock())
- RestoreBlocks.push_back(RestoreBlock);
- return;
- }
-
- // Save refs to entry and return blocks.
- SaveBlocks.push_back(&Fn.front());
- for (MachineBasicBlock &MBB : Fn) {
- if (MBB.isEHFuncletEntry())
- SaveBlocks.push_back(&MBB);
- if (MBB.isReturnBlock())
- RestoreBlocks.push_back(&MBB);
- }
-}
-
-/// StackObjSet - A set of stack object indexes
-typedef SmallSetVector<int, 8> StackObjSet;
-
-/// runOnMachineFunction - Insert prolog/epilog code and replace abstract
-/// frame indexes with appropriate references.
-///
-bool WasmPEI::runOnMachineFunction(MachineFunction &Fn) {
- const Function* F = Fn.getFunction();
- const TargetRegisterInfo *TRI = Fn.getSubtarget().getRegisterInfo();
- const TargetFrameLowering *TFI = Fn.getSubtarget().getFrameLowering();
-
- // LOCALMOD: assert removed from target-independent PEI
- //assert(!Fn.getRegInfo().getNumVirtRegs() && "Regalloc must assign all vregs");
-
- RS = TRI->requiresRegisterScavenging(Fn) ? new RegScavenger() : nullptr;
- FrameIndexVirtualScavenging = TRI->requiresFrameIndexScavenging(Fn);
-
- // Calculate the MaxCallFrameSize and AdjustsStack variables for the
- // function's frame information. Also eliminates call frame pseudo
- // instructions.
- calculateCallsInformation(Fn);
-
- // Determine which of the registers in the callee save list should be saved.
- BitVector SavedRegs;
- TFI->determineCalleeSaves(Fn, SavedRegs, RS);
-
- // Insert spill code for any callee saved registers that are modified.
- assignCalleeSavedSpillSlots(Fn, SavedRegs);
-
- // Determine placement of CSR spill/restore code:
- // place all spills in the entry block, all restores in return blocks.
- calculateSets(Fn);
-
- // Add the code to save and restore the callee saved registers.
- if (!F->hasFnAttribute(Attribute::Naked))
- insertCSRSpillsAndRestores(Fn);
-
- // Allow the target machine to make final modifications to the function
- // before the frame layout is finalized.
- TFI->processFunctionBeforeFrameFinalized(Fn, RS);
-
- // Calculate actual frame offsets for all abstract stack objects...
- calculateFrameObjectOffsets(Fn);
-
- // Add prolog and epilog code to the function. This function is required
- // to align the stack frame as necessary for any stack variables or
- // called functions. Because of this, calculateCalleeSavedRegisters()
- // must be called before this function in order to set the AdjustsStack
- // and MaxCallFrameSize variables.
- if (!F->hasFnAttribute(Attribute::Naked))
- insertPrologEpilogCode(Fn);
-
- // Replace all MO_FrameIndex operands with physical register references
- // and actual offsets.
- //
- replaceFrameIndices(Fn);
-
- // If register scavenging is needed, as we've enabled doing it as a
- // post-pass, scavenge the virtual registers that frame index elimination
- // inserted.
- if (TRI->requiresRegisterScavenging(Fn) && FrameIndexVirtualScavenging) {
- scavengeFrameVirtualRegs(Fn);
- // Clear any vregs created by virtual scavenging.
- // LOCALMOD: made this call conditional with scavengeFrameVirtualregs()
- Fn.getRegInfo().clearVirtRegs();
- }
-
- // Warn on stack size when we exceeds the given limit.
- MachineFrameInfo *MFI = Fn.getFrameInfo();
- uint64_t StackSize = MFI->getStackSize();
- if (WarnStackSize.getNumOccurrences() > 0 && WarnStackSize < StackSize) {
- DiagnosticInfoStackSize DiagStackSize(*F, StackSize);
- F->getContext().diagnose(DiagStackSize);
- }
-
- delete RS;
- SaveBlocks.clear();
- RestoreBlocks.clear();
- return true;
-}
-
-/// calculateCallsInformation - Calculate the MaxCallFrameSize and AdjustsStack
-/// variables for the function's frame information and eliminate call frame
-/// pseudo instructions.
-void WasmPEI::calculateCallsInformation(MachineFunction &Fn) {
- const TargetInstrInfo &TII = *Fn.getSubtarget().getInstrInfo();
- const TargetFrameLowering *TFI = Fn.getSubtarget().getFrameLowering();
- MachineFrameInfo *MFI = Fn.getFrameInfo();
-
- unsigned MaxCallFrameSize = 0;
- bool AdjustsStack = MFI->adjustsStack();
-
- // Get the function call frame set-up and tear-down instruction opcode
- unsigned FrameSetupOpcode = TII.getCallFrameSetupOpcode();
- unsigned FrameDestroyOpcode = TII.getCallFrameDestroyOpcode();
-
- // Early exit for targets which have no call frame setup/destroy pseudo
- // instructions.
- if (FrameSetupOpcode == ~0u && FrameDestroyOpcode == ~0u)
- return;
-
- std::vector<MachineBasicBlock::iterator> FrameSDOps;
- for (MachineFunction::iterator BB = Fn.begin(), E = Fn.end(); BB != E; ++BB)
- for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); ++I)
- if (I->getOpcode() == FrameSetupOpcode ||
- I->getOpcode() == FrameDestroyOpcode) {
- assert(I->getNumOperands() >= 1 && "Call Frame Setup/Destroy Pseudo"
- " instructions should have a single immediate argument!");
- unsigned Size = I->getOperand(0).getImm();
- if (Size > MaxCallFrameSize) MaxCallFrameSize = Size;
- AdjustsStack = true;
- FrameSDOps.push_back(I);
- } else if (I->isInlineAsm()) {
- // Some inline asm's need a stack frame, as indicated by operand 1.
- unsigned ExtraInfo = I->getOperand(InlineAsm::MIOp_ExtraInfo).getImm();
- if (ExtraInfo & InlineAsm::Extra_IsAlignStack)
- AdjustsStack = true;
- }
-
- MFI->setAdjustsStack(AdjustsStack);
- MFI->setMaxCallFrameSize(MaxCallFrameSize);
-
- for (std::vector<MachineBasicBlock::iterator>::iterator
- i = FrameSDOps.begin(), e = FrameSDOps.end(); i != e; ++i) {
- MachineBasicBlock::iterator I = *i;
-
- // If call frames are not being included as part of the stack frame, and
- // the target doesn't indicate otherwise, remove the call frame pseudos
- // here. The sub/add sp instruction pairs are still inserted, but we don't
- // need to track the SP adjustment for frame index elimination.
- if (TFI->canSimplifyCallFramePseudos(Fn))
- TFI->eliminateCallFramePseudoInstr(Fn, *I->getParent(), I);
- }
-}
-
-void WasmPEI::assignCalleeSavedSpillSlots(MachineFunction &F,
- const BitVector &SavedRegs) {
- // These are used to keep track the callee-save area. Initialize them.
- MinCSFrameIndex = INT_MAX;
- MaxCSFrameIndex = 0;
-
- if (SavedRegs.empty())
- return;
-
- const TargetRegisterInfo *RegInfo = F.getSubtarget().getRegisterInfo();
- const MCPhysReg *CSRegs = RegInfo->getCalleeSavedRegs(&F);
-
- std::vector<CalleeSavedInfo> CSI;
- for (unsigned i = 0; CSRegs[i]; ++i) {
- unsigned Reg = CSRegs[i];
- if (SavedRegs.test(Reg))
- CSI.push_back(CalleeSavedInfo(Reg));
- }
-
- const TargetFrameLowering *TFI = F.getSubtarget().getFrameLowering();
- MachineFrameInfo *MFI = F.getFrameInfo();
- if (!TFI->assignCalleeSavedSpillSlots(F, RegInfo, CSI)) {
- // If target doesn't implement this, use generic code.
-
- if (CSI.empty())
- return; // Early exit if no callee saved registers are modified!
-
- unsigned NumFixedSpillSlots;
- const TargetFrameLowering::SpillSlot *FixedSpillSlots =
- TFI->getCalleeSavedSpillSlots(NumFixedSpillSlots);
-
- // Now that we know which registers need to be saved and restored, allocate
- // stack slots for them.
- for (std::vector<CalleeSavedInfo>::iterator I = CSI.begin(), E = CSI.end();
- I != E; ++I) {
- unsigned Reg = I->getReg();
- const TargetRegisterClass *RC = RegInfo->getMinimalPhysRegClass(Reg);
-
- int FrameIdx;
- if (RegInfo->hasReservedSpillSlot(F, Reg, FrameIdx)) {
- I->setFrameIdx(FrameIdx);
- continue;
- }
-
- // Check to see if this physreg must be spilled to a particular stack slot
- // on this target.
- const TargetFrameLowering::SpillSlot *FixedSlot = FixedSpillSlots;
- while (FixedSlot != FixedSpillSlots + NumFixedSpillSlots &&
- FixedSlot->Reg != Reg)
- ++FixedSlot;
-
- if (FixedSlot == FixedSpillSlots + NumFixedSpillSlots) {
- // Nope, just spill it anywhere convenient.
- unsigned Align = RC->getAlignment();
- unsigned StackAlign = TFI->getStackAlignment();
-
- // We may not be able to satisfy the desired alignment specification of
- // the TargetRegisterClass if the stack alignment is smaller. Use the
- // min.
- Align = std::min(Align, StackAlign);
- FrameIdx = MFI->CreateStackObject(RC->getSize(), Align, true);
- if ((unsigned)FrameIdx < MinCSFrameIndex) MinCSFrameIndex = FrameIdx;
- if ((unsigned)FrameIdx > MaxCSFrameIndex) MaxCSFrameIndex = FrameIdx;
- } else {
- // Spill it to the stack where we must.
- FrameIdx =
- MFI->CreateFixedSpillStackObject(RC->getSize(), FixedSlot->Offset);
- }
-
- I->setFrameIdx(FrameIdx);
- }
- }
-
- MFI->setCalleeSavedInfo(CSI);
-}
-
-/// Helper function to update the liveness information for the callee-saved
-/// registers.
-static void updateLiveness(MachineFunction &MF) {
- MachineFrameInfo *MFI = MF.getFrameInfo();
- // Visited will contain all the basic blocks that are in the region
- // where the callee saved registers are alive:
- // - Anything that is not Save or Restore -> LiveThrough.
- // - Save -> LiveIn.
- // - Restore -> LiveOut.
- // The live-out is not attached to the block, so no need to keep
- // Restore in this set.
- SmallPtrSet<MachineBasicBlock *, 8> Visited;
- SmallVector<MachineBasicBlock *, 8> WorkList;
- MachineBasicBlock *Entry = &MF.front();
- MachineBasicBlock *Save = MFI->getSavePoint();
-
- if (!Save)
- Save = Entry;
-
- if (Entry != Save) {
- WorkList.push_back(Entry);
- Visited.insert(Entry);
- }
- Visited.insert(Save);
-
- MachineBasicBlock *Restore = MFI->getRestorePoint();
- if (Restore)
- // By construction Restore cannot be visited, otherwise it
- // means there exists a path to Restore that does not go
- // through Save.
- WorkList.push_back(Restore);
-
- while (!WorkList.empty()) {
- const MachineBasicBlock *CurBB = WorkList.pop_back_val();
- // By construction, the region that is after the save point is
- // dominated by the Save and post-dominated by the Restore.
- if (CurBB == Save && Save != Restore)
- continue;
- // Enqueue all the successors not already visited.
- // Those are by construction either before Save or after Restore.
- for (MachineBasicBlock *SuccBB : CurBB->successors())
- if (Visited.insert(SuccBB).second)
- WorkList.push_back(SuccBB);
- }
-
- const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
-
- for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
- for (MachineBasicBlock *MBB : Visited) {
- MCPhysReg Reg = CSI[i].getReg();
- // Add the callee-saved register as live-in.
- // It's killed at the spill.
- if (!MBB->isLiveIn(Reg))
- MBB->addLiveIn(Reg);
- }
- }
-}
-
-/// insertCSRSpillsAndRestores - Insert spill and restore code for
-/// callee saved registers used in the function.
-///
-void WasmPEI::insertCSRSpillsAndRestores(MachineFunction &Fn) {
- // Get callee saved register information.
- MachineFrameInfo *MFI = Fn.getFrameInfo();
- const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
-
- MFI->setCalleeSavedInfoValid(true);
-
- // Early exit if no callee saved registers are modified!
- if (CSI.empty())
- return;
-
- const TargetInstrInfo &TII = *Fn.getSubtarget().getInstrInfo();
- const TargetFrameLowering *TFI = Fn.getSubtarget().getFrameLowering();
- const TargetRegisterInfo *TRI = Fn.getSubtarget().getRegisterInfo();
- MachineBasicBlock::iterator I;
-
- // Spill using target interface.
- for (MachineBasicBlock *SaveBlock : SaveBlocks) {
- I = SaveBlock->begin();
- if (!TFI->spillCalleeSavedRegisters(*SaveBlock, I, CSI, TRI)) {
- for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
- // Insert the spill to the stack frame.
- unsigned Reg = CSI[i].getReg();
- const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
- TII.storeRegToStackSlot(*SaveBlock, I, Reg, true, CSI[i].getFrameIdx(),
- RC, TRI);
- }
- }
- // Update the live-in information of all the blocks up to the save point.
- updateLiveness(Fn);
- }
-
- // Restore using target interface.
- for (MachineBasicBlock *MBB : RestoreBlocks) {
- I = MBB->end();
-
- // Skip over all terminator instructions, which are part of the return
- // sequence.
- MachineBasicBlock::iterator I2 = I;
- while (I2 != MBB->begin() && (--I2)->isTerminator())
- I = I2;
-
- bool AtStart = I == MBB->begin();
- MachineBasicBlock::iterator BeforeI = I;
- if (!AtStart)
- --BeforeI;
-
- // Restore all registers immediately before the return and any
- // terminators that precede it.
- if (!TFI->restoreCalleeSavedRegisters(*MBB, I, CSI, TRI)) {
- for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
- unsigned Reg = CSI[i].getReg();
- const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
- TII.loadRegFromStackSlot(*MBB, I, Reg, CSI[i].getFrameIdx(), RC, TRI);
- assert(I != MBB->begin() &&
- "loadRegFromStackSlot didn't insert any code!");
- // Insert in reverse order. loadRegFromStackSlot can insert
- // multiple instructions.
- if (AtStart)
- I = MBB->begin();
- else {
- I = BeforeI;
- ++I;
- }
- }
- }
- }
-}
-
-/// AdjustStackOffset - Helper function used to adjust the stack frame offset.
-static inline void
-AdjustStackOffset(MachineFrameInfo *MFI, int FrameIdx,
- bool StackGrowsDown, int64_t &Offset,
- unsigned &MaxAlign, unsigned Skew) {
- // If the stack grows down, add the object size to find the lowest address.
- if (StackGrowsDown)
- Offset += MFI->getObjectSize(FrameIdx);
-
- unsigned Align = MFI->getObjectAlignment(FrameIdx);
-
- // If the alignment of this object is greater than that of the stack, then
- // increase the stack alignment to match.
- MaxAlign = std::max(MaxAlign, Align);
-
- // Adjust to alignment boundary.
- Offset = alignTo(Offset, Align, Skew);
-
- if (StackGrowsDown) {
- DEBUG(dbgs() << "alloc FI(" << FrameIdx << ") at SP[" << -Offset << "]\n");
- MFI->setObjectOffset(FrameIdx, -Offset); // Set the computed offset
- } else {
- DEBUG(dbgs() << "alloc FI(" << FrameIdx << ") at SP[" << Offset << "]\n");
- MFI->setObjectOffset(FrameIdx, Offset);
- Offset += MFI->getObjectSize(FrameIdx);
- }
-}
-
-/// AssignProtectedObjSet - Helper function to assign large stack objects (i.e.,
-/// those required to be close to the Stack Protector) to stack offsets.
-static void
-AssignProtectedObjSet(const StackObjSet &UnassignedObjs,
- SmallSet<int, 16> &ProtectedObjs,
- MachineFrameInfo *MFI, bool StackGrowsDown,
- int64_t &Offset, unsigned &MaxAlign, unsigned Skew) {
-
- for (StackObjSet::const_iterator I = UnassignedObjs.begin(),
- E = UnassignedObjs.end(); I != E; ++I) {
- int i = *I;
- AdjustStackOffset(MFI, i, StackGrowsDown, Offset, MaxAlign, Skew);
- ProtectedObjs.insert(i);
- }
-}
-
-/// calculateFrameObjectOffsets - Calculate actual frame offsets for all of the
-/// abstract stack objects.
-///
-void WasmPEI::calculateFrameObjectOffsets(MachineFunction &Fn) {
- const TargetFrameLowering &TFI = *Fn.getSubtarget().getFrameLowering();
- StackProtector *SP = &getAnalysis<StackProtector>();
-
- bool StackGrowsDown =
- TFI.getStackGrowthDirection() == TargetFrameLowering::StackGrowsDown;
-
- // Loop over all of the stack objects, assigning sequential addresses...
- MachineFrameInfo *MFI = Fn.getFrameInfo();
-
- // Start at the beginning of the local area.
- // The Offset is the distance from the stack top in the direction
- // of stack growth -- so it's always nonnegative.
- int LocalAreaOffset = TFI.getOffsetOfLocalArea();
- if (StackGrowsDown)
- LocalAreaOffset = -LocalAreaOffset;
- assert(LocalAreaOffset >= 0
- && "Local area offset should be in direction of stack growth");
- int64_t Offset = LocalAreaOffset;
-
- // Skew to be applied to alignment.
- unsigned Skew = TFI.getStackAlignmentSkew(Fn);
-
- // If there are fixed sized objects that are preallocated in the local area,
- // non-fixed objects can't be allocated right at the start of local area.
- // We currently don't support filling in holes in between fixed sized
- // objects, so we adjust 'Offset' to point to the end of last fixed sized
- // preallocated object.
- for (int i = MFI->getObjectIndexBegin(); i != 0; ++i) {
- int64_t FixedOff;
- if (StackGrowsDown) {
- // The maximum distance from the stack pointer is at lower address of
- // the object -- which is given by offset. For down growing stack
- // the offset is negative, so we negate the offset to get the distance.
- FixedOff = -MFI->getObjectOffset(i);
- } else {
- // The maximum distance from the start pointer is at the upper
- // address of the object.
- FixedOff = MFI->getObjectOffset(i) + MFI->getObjectSize(i);
- }
- if (FixedOff > Offset) Offset = FixedOff;
- }
-
- // First assign frame offsets to stack objects that are used to spill
- // callee saved registers.
- if (StackGrowsDown) {
- for (unsigned i = MinCSFrameIndex; i <= MaxCSFrameIndex; ++i) {
- // If the stack grows down, we need to add the size to find the lowest
- // address of the object.
- Offset += MFI->getObjectSize(i);
-
- unsigned Align = MFI->getObjectAlignment(i);
- // Adjust to alignment boundary
- Offset = alignTo(Offset, Align, Skew);
-
- MFI->setObjectOffset(i, -Offset); // Set the computed offset
- }
- } else {
- int MaxCSFI = MaxCSFrameIndex, MinCSFI = MinCSFrameIndex;
- for (int i = MaxCSFI; i >= MinCSFI ; --i) {
- unsigned Align = MFI->getObjectAlignment(i);
- // Adjust to alignment boundary
- Offset = alignTo(Offset, Align, Skew);
-
- MFI->setObjectOffset(i, Offset);
- Offset += MFI->getObjectSize(i);
- }
- }
-
- unsigned MaxAlign = MFI->getMaxAlignment();
-
- // Make sure the special register scavenging spill slot is closest to the
- // incoming stack pointer if a frame pointer is required and is closer
- // to the incoming rather than the final stack pointer.
- const TargetRegisterInfo *RegInfo = Fn.getSubtarget().getRegisterInfo();
- bool EarlyScavengingSlots = (TFI.hasFP(Fn) &&
- TFI.isFPCloseToIncomingSP() &&
- RegInfo->useFPForScavengingIndex(Fn) &&
- !RegInfo->needsStackRealignment(Fn));
- if (RS && EarlyScavengingSlots) {
- SmallVector<int, 2> SFIs;
- RS->getScavengingFrameIndices(SFIs);
- for (SmallVectorImpl<int>::iterator I = SFIs.begin(),
- IE = SFIs.end(); I != IE; ++I)
- AdjustStackOffset(MFI, *I, StackGrowsDown, Offset, MaxAlign, Skew);
- }
-
- // FIXME: Once this is working, then enable flag will change to a target
- // check for whether the frame is large enough to want to use virtual
- // frame index registers. Functions which don't want/need this optimization
- // will continue to use the existing code path.
- if (MFI->getUseLocalStackAllocationBlock()) {
- unsigned Align = MFI->getLocalFrameMaxAlign();
-
- // Adjust to alignment boundary.
- Offset = alignTo(Offset, Align, Skew);
-
- DEBUG(dbgs() << "Local frame base offset: " << Offset << "\n");
-
- // Resolve offsets for objects in the local block.
- for (unsigned i = 0, e = MFI->getLocalFrameObjectCount(); i != e; ++i) {
- std::pair<int, int64_t> Entry = MFI->getLocalFrameObjectMap(i);
- int64_t FIOffset = (StackGrowsDown ? -Offset : Offset) + Entry.second;
- DEBUG(dbgs() << "alloc FI(" << Entry.first << ") at SP[" <<
- FIOffset << "]\n");
- MFI->setObjectOffset(Entry.first, FIOffset);
- }
- // Allocate the local block
- Offset += MFI->getLocalFrameSize();
-
- MaxAlign = std::max(Align, MaxAlign);
- }
-
- // Make sure that the stack protector comes before the local variables on the
- // stack.
- SmallSet<int, 16> ProtectedObjs;
- if (MFI->getStackProtectorIndex() >= 0) {
- StackObjSet LargeArrayObjs;
- StackObjSet SmallArrayObjs;
- StackObjSet AddrOfObjs;
-
- AdjustStackOffset(MFI, MFI->getStackProtectorIndex(), StackGrowsDown,
- Offset, MaxAlign, Skew);
-
- // Assign large stack objects first.
- for (unsigned i = 0, e = MFI->getObjectIndexEnd(); i != e; ++i) {
- if (MFI->isObjectPreAllocated(i) &&
- MFI->getUseLocalStackAllocationBlock())
- continue;
- if (i >= MinCSFrameIndex && i <= MaxCSFrameIndex)
- continue;
- if (RS && RS->isScavengingFrameIndex((int)i))
- continue;
- if (MFI->isDeadObjectIndex(i))
- continue;
- if (MFI->getStackProtectorIndex() == (int)i)
- continue;
-
- switch (SP->getSSPLayout(MFI->getObjectAllocation(i))) {
- case StackProtector::SSPLK_None:
- continue;
- case StackProtector::SSPLK_SmallArray:
- SmallArrayObjs.insert(i);
- continue;
- case StackProtector::SSPLK_AddrOf:
- AddrOfObjs.insert(i);
- continue;
- case StackProtector::SSPLK_LargeArray:
- LargeArrayObjs.insert(i);
- continue;
- }
- llvm_unreachable("Unexpected SSPLayoutKind.");
- }
-
- AssignProtectedObjSet(LargeArrayObjs, ProtectedObjs, MFI, StackGrowsDown,
- Offset, MaxAlign, Skew);
- AssignProtectedObjSet(SmallArrayObjs, ProtectedObjs, MFI, StackGrowsDown,
- Offset, MaxAlign, Skew);
- AssignProtectedObjSet(AddrOfObjs, ProtectedObjs, MFI, StackGrowsDown,
- Offset, MaxAlign, Skew);
- }
-
- // Then assign frame offsets to stack objects that are not used to spill
- // callee saved registers.
- for (unsigned i = 0, e = MFI->getObjectIndexEnd(); i != e; ++i) {
- if (MFI->isObjectPreAllocated(i) &&
- MFI->getUseLocalStackAllocationBlock())
- continue;
- if (i >= MinCSFrameIndex && i <= MaxCSFrameIndex)
- continue;
- if (RS && RS->isScavengingFrameIndex((int)i))
- continue;
- if (MFI->isDeadObjectIndex(i))
- continue;
- if (MFI->getStackProtectorIndex() == (int)i)
- continue;
- if (ProtectedObjs.count(i))
- continue;
-
- AdjustStackOffset(MFI, i, StackGrowsDown, Offset, MaxAlign, Skew);
- }
-
- // Make sure the special register scavenging spill slot is closest to the
- // stack pointer.
- if (RS && !EarlyScavengingSlots) {
- SmallVector<int, 2> SFIs;
- RS->getScavengingFrameIndices(SFIs);
- for (SmallVectorImpl<int>::iterator I = SFIs.begin(),
- IE = SFIs.end(); I != IE; ++I)
- AdjustStackOffset(MFI, *I, StackGrowsDown, Offset, MaxAlign, Skew);
- }
-
- if (!TFI.targetHandlesStackFrameRounding()) {
- // If we have reserved argument space for call sites in the function
- // immediately on entry to the current function, count it as part of the
- // overall stack size.
- if (MFI->adjustsStack() && TFI.hasReservedCallFrame(Fn))
- Offset += MFI->getMaxCallFrameSize();
-
- // Round up the size to a multiple of the alignment. If the function has
- // any calls or alloca's, align to the target's StackAlignment value to
- // ensure that the callee's frame or the alloca data is suitably aligned;
- // otherwise, for leaf functions, align to the TransientStackAlignment
- // value.
- unsigned StackAlign;
- if (MFI->adjustsStack() || MFI->hasVarSizedObjects() ||
- (RegInfo->needsStackRealignment(Fn) && MFI->getObjectIndexEnd() != 0))
- StackAlign = TFI.getStackAlignment();
- else
- StackAlign = TFI.getTransientStackAlignment();
-
- // If the frame pointer is eliminated, all frame offsets will be relative to
- // SP not FP. Align to MaxAlign so this works.
- StackAlign = std::max(StackAlign, MaxAlign);
- Offset = alignTo(Offset, StackAlign, Skew);
- }
-
- // Update frame info to pretend that this is part of the stack...
- int64_t StackSize = Offset - LocalAreaOffset;
- MFI->setStackSize(StackSize);
- NumBytesStackSpace += StackSize;
-}
-
-/// insertPrologEpilogCode - Scan the function for modified callee saved
-/// registers, insert spill code for these callee saved registers, then add
-/// prolog and epilog code to the function.
-///
-void WasmPEI::insertPrologEpilogCode(MachineFunction &Fn) {
- const TargetFrameLowering &TFI = *Fn.getSubtarget().getFrameLowering();
-
- // Add prologue to the function...
- for (MachineBasicBlock *SaveBlock : SaveBlocks)
- TFI.emitPrologue(Fn, *SaveBlock);
-
- // Add epilogue to restore the callee-save registers in each exiting block.
- for (MachineBasicBlock *RestoreBlock : RestoreBlocks)
- TFI.emitEpilogue(Fn, *RestoreBlock);
-
- for (MachineBasicBlock *SaveBlock : SaveBlocks)
- TFI.inlineStackProbe(Fn, *SaveBlock);
-
- // Emit additional code that is required to support segmented stacks, if
- // we've been asked for it. This, when linked with a runtime with support
- // for segmented stacks (libgcc is one), will result in allocating stack
- // space in small chunks instead of one large contiguous block.
- if (Fn.shouldSplitStack()) {
- for (MachineBasicBlock *SaveBlock : SaveBlocks)
- TFI.adjustForSegmentedStacks(Fn, *SaveBlock);
- }
-
- // Emit additional code that is required to explicitly handle the stack in
- // HiPE native code (if needed) when loaded in the Erlang/OTP runtime. The
- // approach is rather similar to that of Segmented Stacks, but it uses a
- // different conditional check and another BIF for allocating more stack
- // space.
- if (Fn.getFunction()->getCallingConv() == CallingConv::HiPE)
- for (MachineBasicBlock *SaveBlock : SaveBlocks)
- TFI.adjustForHiPEPrologue(Fn, *SaveBlock);
-}
-
-/// replaceFrameIndices - Replace all MO_FrameIndex operands with physical
-/// register references and actual offsets.
-///
-void WasmPEI::replaceFrameIndices(MachineFunction &Fn) {
- const TargetFrameLowering &TFI = *Fn.getSubtarget().getFrameLowering();
- if (!TFI.needsFrameIndexResolution(Fn)) return;
-
- // Store SPAdj at exit of a basic block.
- SmallVector<int, 8> SPState;
- SPState.resize(Fn.getNumBlockIDs());
- SmallPtrSet<MachineBasicBlock*, 8> Reachable;
-
- // Iterate over the reachable blocks in DFS order.
- for (auto DFI = df_ext_begin(&Fn, Reachable), DFE = df_ext_end(&Fn, Reachable);
- DFI != DFE; ++DFI) {
- int SPAdj = 0;
- // Check the exit state of the DFS stack predecessor.
- if (DFI.getPathLength() >= 2) {
- MachineBasicBlock *StackPred = DFI.getPath(DFI.getPathLength() - 2);
- assert(Reachable.count(StackPred) &&
- "DFS stack predecessor is already visited.\n");
- SPAdj = SPState[StackPred->getNumber()];
- }
- MachineBasicBlock *BB = *DFI;
- replaceFrameIndices(BB, Fn, SPAdj);
- SPState[BB->getNumber()] = SPAdj;
- }
-
- // Handle the unreachable blocks.
- for (auto &BB : Fn) {
- if (Reachable.count(&BB))
- // Already handled in DFS traversal.
- continue;
- int SPAdj = 0;
- replaceFrameIndices(&BB, Fn, SPAdj);
- }
-}
-
-void WasmPEI::replaceFrameIndices(MachineBasicBlock *BB, MachineFunction &Fn,
- int &SPAdj) {
- assert(Fn.getSubtarget().getRegisterInfo() &&
- "getRegisterInfo() must be implemented!");
- const TargetInstrInfo &TII = *Fn.getSubtarget().getInstrInfo();
- const TargetRegisterInfo &TRI = *Fn.getSubtarget().getRegisterInfo();
- const TargetFrameLowering *TFI = Fn.getSubtarget().getFrameLowering();
- unsigned FrameSetupOpcode = TII.getCallFrameSetupOpcode();
- unsigned FrameDestroyOpcode = TII.getCallFrameDestroyOpcode();
-
- if (RS && !FrameIndexVirtualScavenging) RS->enterBasicBlock(*BB);
-
- bool InsideCallSequence = false;
-
- for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); ) {
-
- if (I->getOpcode() == FrameSetupOpcode ||
- I->getOpcode() == FrameDestroyOpcode) {
- InsideCallSequence = (I->getOpcode() == FrameSetupOpcode);
- SPAdj += TII.getSPAdjust(I);
- I = TFI->eliminateCallFramePseudoInstr(Fn, *BB, I);
- continue;
- }
-
- MachineInstr *MI = I;
- bool DoIncr = true;
- for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
- if (!MI->getOperand(i).isFI())
- continue;
-
- // Frame indices in debug values are encoded in a target independent
- // way with simply the frame index and offset rather than any
- // target-specific addressing mode.
- if (MI->isDebugValue()) {
- assert(i == 0 && "Frame indices can only appear as the first "
- "operand of a DBG_VALUE machine instruction");
- unsigned Reg;
- MachineOperand &Offset = MI->getOperand(1);
- Offset.setImm(Offset.getImm() +
- TFI->getFrameIndexReference(
- Fn, MI->getOperand(0).getIndex(), Reg));
- MI->getOperand(0).ChangeToRegister(Reg, false /*isDef*/);
- continue;
- }
-
- // TODO: This code should be commoned with the code for
- // PATCHPOINT. There's no good reason for the difference in
- // implementation other than historical accident. The only
- // remaining difference is the unconditional use of the stack
- // pointer as the base register.
- if (MI->getOpcode() == TargetOpcode::STATEPOINT) {
- assert((!MI->isDebugValue() || i == 0) &&
- "Frame indicies can only appear as the first operand of a "
- "DBG_VALUE machine instruction");
- unsigned Reg;
- MachineOperand &Offset = MI->getOperand(i + 1);
- const unsigned refOffset =
- TFI->getFrameIndexReferenceFromSP(Fn, MI->getOperand(i).getIndex(),
- Reg);
-
- Offset.setImm(Offset.getImm() + refOffset);
- MI->getOperand(i).ChangeToRegister(Reg, false /*isDef*/);
- continue;
- }
-
- // Some instructions (e.g. inline asm instructions) can have
- // multiple frame indices and/or cause eliminateFrameIndex
- // to insert more than one instruction. We need the register
- // scavenger to go through all of these instructions so that
- // it can update its register information. We keep the
- // iterator at the point before insertion so that we can
- // revisit them in full.
- bool AtBeginning = (I == BB->begin());
- if (!AtBeginning) --I;
-
- // If this instruction has a FrameIndex operand, we need to
- // use that target machine register info object to eliminate
- // it.
- TRI.eliminateFrameIndex(MI, SPAdj, i,
- FrameIndexVirtualScavenging ? nullptr : RS);
-
- // Reset the iterator if we were at the beginning of the BB.
- if (AtBeginning) {
- I = BB->begin();
- DoIncr = false;
- }
-
- MI = nullptr;
- 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.
- if (RS && !FrameIndexVirtualScavenging && MI) RS->forward(MI);
- }
-}
-
-/// scavengeFrameVirtualRegs - Replace all frame index virtual registers
-/// with physical registers. Use the register scavenger to find an
-/// appropriate register to use.
-///
-/// FIXME: Iterating over the instruction stream is unnecessary. We can simply
-/// iterate over the vreg use list, which at this point only contains machine
-/// operands for which eliminateFrameIndex need a new scratch reg.
-void
-WasmPEI::scavengeFrameVirtualRegs(MachineFunction &Fn) {
- // Run through the instructions and find any virtual registers.
- for (MachineFunction::iterator BB = Fn.begin(),
- E = Fn.end(); BB != E; ++BB) {
- RS->enterBasicBlock(*BB);
-
- int SPAdj = 0;
-
- // The instruction stream may change in the loop, so check BB->end()
- // directly.
- for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); ) {
- // We might end up here again with a NULL iterator if we scavenged a
- // register for which we inserted spill code for definition by what was
- // originally the first instruction in BB.
- if (I == MachineBasicBlock::iterator(nullptr))
- I = BB->begin();
-
- MachineInstr *MI = I;
- MachineBasicBlock::iterator J = std::next(I);
- MachineBasicBlock::iterator P =
- I == BB->begin() ? MachineBasicBlock::iterator(nullptr)
- : std::prev(I);
-
- // RS should process this instruction before we might scavenge at this
- // location. This is because we might be replacing a virtual register
- // defined by this instruction, and if so, registers killed by this
- // instruction are available, and defined registers are not.
- RS->forward(I);
-
- for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
- if (MI->getOperand(i).isReg()) {
- MachineOperand &MO = MI->getOperand(i);
- unsigned Reg = MO.getReg();
- if (Reg == 0)
- continue;
- if (!TargetRegisterInfo::isVirtualRegister(Reg))
- continue;
-
- // When we first encounter a new virtual register, it
- // must be a definition.
- assert(MI->getOperand(i).isDef() &&
- "frame index virtual missing def!");
- // Scavenge a new scratch register
- const TargetRegisterClass *RC = Fn.getRegInfo().getRegClass(Reg);
- unsigned ScratchReg = RS->scavengeRegister(RC, J, SPAdj);
-
- ++NumScavengedRegs;
-
- // Replace this reference to the virtual register with the
- // scratch register.
- assert (ScratchReg && "Missing scratch register!");
- Fn.getRegInfo().replaceRegWith(Reg, ScratchReg);
-
- // Because this instruction was processed by the RS before this
- // register was allocated, make sure that the RS now records the
- // register as being used.
- RS->setRegUsed(ScratchReg);
- }
- }
-
- // If the scavenger needed to use one of its spill slots, the
- // spill code will have been inserted in between I and J. This is a
- // problem because we need the spill code before I: Move I to just
- // prior to J.
- if (I != std::prev(J)) {
- BB->splice(J, &*BB, I);
-
- // Before we move I, we need to prepare the RS to visit I again.
- // Specifically, RS will assert if it sees uses of registers that
- // it believes are undefined. Because we have already processed
- // register kills in I, when it visits I again, it will believe that
- // those registers are undefined. To avoid this situation, unprocess
- // the instruction I.
- assert(RS->getCurrentPosition() == I &&
- "The register scavenger has an unexpected position");
- I = P;
- RS->unprocess(P);
- } else
- ++I;
- }
- }
-}
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