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148c29c710
Recommitting r288293 with some extra fixes for GlobalISel code. Most of the exception handling members in MachineModuleInfo is actually per function data (talks about the "current function") so it is better to keep it at the function instead of the module. This is a necessary step to have machine module passes work properly. Also: - Rename TidyLandingPads() to tidyLandingPads() - Use doxygen member groups instead of "//===- EH ---"... so it is clear where a group ends. - I had to add an ugly const_cast at two places in the AsmPrinter because the available MachineFunction pointers are const, but the code wants to call tidyLandingPads() in between (markFunctionEnd()/endFunction()). Differential Revision: https://reviews.llvm.org/D27227 llvm-svn: 288405
105 lines
4.0 KiB
C++
105 lines
4.0 KiB
C++
//===----- TargetFrameLoweringImpl.cpp - Implement target frame interface --==//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// Implements the layout of a stack frame on the target machine.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/ADT/BitVector.h"
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#include "llvm/CodeGen/MachineFrameInfo.h"
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#include "llvm/CodeGen/MachineFunction.h"
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#include "llvm/CodeGen/MachineModuleInfo.h"
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#include "llvm/CodeGen/MachineRegisterInfo.h"
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#include "llvm/CodeGen/TargetPassConfig.h"
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#include "llvm/IR/CallingConv.h"
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#include "llvm/IR/Function.h"
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#include "llvm/Target/TargetFrameLowering.h"
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#include "llvm/Target/TargetRegisterInfo.h"
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#include "llvm/Target/TargetSubtargetInfo.h"
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#include <cstdlib>
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using namespace llvm;
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TargetFrameLowering::~TargetFrameLowering() {
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}
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/// The default implementation just looks at attribute "no-frame-pointer-elim".
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bool TargetFrameLowering::noFramePointerElim(const MachineFunction &MF) const {
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auto Attr = MF.getFunction()->getFnAttribute("no-frame-pointer-elim");
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return Attr.getValueAsString() == "true";
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}
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/// Returns the displacement from the frame register to the stack
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/// frame of the specified index, along with the frame register used
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/// (in output arg FrameReg). This is the default implementation which
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/// is overridden for some targets.
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int TargetFrameLowering::getFrameIndexReference(const MachineFunction &MF,
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int FI, unsigned &FrameReg) const {
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const MachineFrameInfo &MFI = MF.getFrameInfo();
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const TargetRegisterInfo *RI = MF.getSubtarget().getRegisterInfo();
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// By default, assume all frame indices are referenced via whatever
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// getFrameRegister() says. The target can override this if it's doing
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// something different.
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FrameReg = RI->getFrameRegister(MF);
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return MFI.getObjectOffset(FI) + MFI.getStackSize() -
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getOffsetOfLocalArea() + MFI.getOffsetAdjustment();
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}
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bool TargetFrameLowering::needsFrameIndexResolution(
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const MachineFunction &MF) const {
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return MF.getFrameInfo().hasStackObjects();
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}
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void TargetFrameLowering::determineCalleeSaves(MachineFunction &MF,
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BitVector &SavedRegs,
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RegScavenger *RS) const {
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const TargetRegisterInfo &TRI = *MF.getSubtarget().getRegisterInfo();
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// Resize before the early returns. Some backends expect that
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// SavedRegs.size() == TRI.getNumRegs() after this call even if there are no
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// saved registers.
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SavedRegs.resize(TRI.getNumRegs());
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// When interprocedural register allocation is enabled caller saved registers
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// are preferred over callee saved registers.
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if (MF.getTarget().Options.EnableIPRA && isSafeForNoCSROpt(MF.getFunction()))
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return;
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// Get the callee saved register list...
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const MCPhysReg *CSRegs = TRI.getCalleeSavedRegs(&MF);
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// Early exit if there are no callee saved registers.
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if (!CSRegs || CSRegs[0] == 0)
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return;
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// In Naked functions we aren't going to save any registers.
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if (MF.getFunction()->hasFnAttribute(Attribute::Naked))
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return;
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// Functions which call __builtin_unwind_init get all their registers saved.
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bool CallsUnwindInit = MF.callsUnwindInit();
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const MachineRegisterInfo &MRI = MF.getRegInfo();
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for (unsigned i = 0; CSRegs[i]; ++i) {
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unsigned Reg = CSRegs[i];
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if (CallsUnwindInit || MRI.isPhysRegModified(Reg))
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SavedRegs.set(Reg);
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}
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}
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unsigned TargetFrameLowering::getStackAlignmentSkew(
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const MachineFunction &MF) const {
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// When HHVM function is called, the stack is skewed as the return address
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// is removed from the stack before we enter the function.
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if (LLVM_UNLIKELY(MF.getFunction()->getCallingConv() == CallingConv::HHVM))
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return MF.getTarget().getPointerSize();
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return 0;
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}
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