-//====- SparcFrameLowering.cpp - Sparc Frame Information -------*- C++ -*-====//
+//===-- SparcFrameLowering.cpp - Sparc Frame Information ------------------===//
//
// The LLVM Compiler Infrastructure
//
#include "SparcFrameLowering.h"
#include "SparcInstrInfo.h"
#include "SparcMachineFunctionInfo.h"
-#include "llvm/Function.h"
+#include "SparcSubtarget.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
-#include "llvm/Target/TargetData.h"
-#include "llvm/Target/TargetOptions.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/Function.h"
#include "llvm/Support/CommandLine.h"
+#include "llvm/Target/TargetOptions.h"
using namespace llvm;
-void SparcFrameLowering::emitPrologue(MachineFunction &MF) const {
- MachineBasicBlock &MBB = MF.front();
+static cl::opt<bool>
+DisableLeafProc("disable-sparc-leaf-proc",
+ cl::init(false),
+ cl::desc("Disable Sparc leaf procedure optimization."),
+ cl::Hidden);
+
+SparcFrameLowering::SparcFrameLowering(const SparcSubtarget &ST)
+ : TargetFrameLowering(TargetFrameLowering::StackGrowsDown,
+ ST.is64Bit() ? 16 : 8, 0, ST.is64Bit() ? 16 : 8) {}
+
+void SparcFrameLowering::emitSPAdjustment(MachineFunction &MF,
+ MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator MBBI,
+ int NumBytes,
+ unsigned ADDrr,\r
+ unsigned ADDri) const {\r
+\r
+ DebugLoc dl;\r
+ const SparcInstrInfo &TII =\r
+ *static_cast<const SparcInstrInfo *>(MF.getSubtarget().getInstrInfo());\r
+\r
+ if (NumBytes >= -4096 && NumBytes < 4096) {
+ BuildMI(MBB, MBBI, dl, TII.get(ADDri), SP::O6)
+ .addReg(SP::O6).addImm(NumBytes);
+ return;
+ }
+
+ // Emit this the hard way. This clobbers G1 which we always know is
+ // available here.
+ if (NumBytes >= 0) {
+ // Emit nonnegative numbers with sethi + or.
+ // sethi %hi(NumBytes), %g1
+ // or %g1, %lo(NumBytes), %g1
+ // add %sp, %g1, %sp
+ BuildMI(MBB, MBBI, dl, TII.get(SP::SETHIi), SP::G1)
+ .addImm(HI22(NumBytes));
+ BuildMI(MBB, MBBI, dl, TII.get(SP::ORri), SP::G1)
+ .addReg(SP::G1).addImm(LO10(NumBytes));
+ BuildMI(MBB, MBBI, dl, TII.get(ADDrr), SP::O6)
+ .addReg(SP::O6).addReg(SP::G1);
+ return ;
+ }
+
+ // Emit negative numbers with sethi + xor.
+ // sethi %hix(NumBytes), %g1
+ // xor %g1, %lox(NumBytes), %g1
+ // add %sp, %g1, %sp
+ BuildMI(MBB, MBBI, dl, TII.get(SP::SETHIi), SP::G1)
+ .addImm(HIX22(NumBytes));
+ BuildMI(MBB, MBBI, dl, TII.get(SP::XORri), SP::G1)
+ .addReg(SP::G1).addImm(LOX10(NumBytes));
+ BuildMI(MBB, MBBI, dl, TII.get(ADDrr), SP::O6)
+ .addReg(SP::O6).addReg(SP::G1);
+}
+
+void SparcFrameLowering::emitPrologue(MachineFunction &MF,
+ MachineBasicBlock &MBB) const {
+ SparcMachineFunctionInfo *FuncInfo = MF.getInfo<SparcMachineFunctionInfo>();
+
+ assert(&MF.front() == &MBB && "Shrink-wrapping not yet supported");
MachineFrameInfo *MFI = MF.getFrameInfo();
const SparcInstrInfo &TII =
- *static_cast<const SparcInstrInfo*>(MF.getTarget().getInstrInfo());
+ *static_cast<const SparcInstrInfo *>(MF.getSubtarget().getInstrInfo());
+ const SparcRegisterInfo &RegInfo =
+ *static_cast<const SparcRegisterInfo *>(MF.getSubtarget().getRegisterInfo());
MachineBasicBlock::iterator MBBI = MBB.begin();
- DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
+ // Debug location must be unknown since the first debug location is used
+ // to determine the end of the prologue.
+ DebugLoc dl;
+ bool NeedsStackRealignment = RegInfo.needsStackRealignment(MF);
+
+ // FIXME: unfortunately, returning false from canRealignStack
+ // actually just causes needsStackRealignment to return false,
+ // rather than reporting an error, as would be sensible. This is
+ // poor, but fixing that bogosity is going to be a large project.
+ // For now, just see if it's lied, and report an error here.
+ if (!NeedsStackRealignment && MFI->getMaxAlignment() > getStackAlignment())
+ report_fatal_error("Function \"" + Twine(MF.getName()) + "\" required "
+ "stack re-alignment, but LLVM couldn't handle it "
+ "(probably because it has a dynamic alloca).");
// Get the number of bytes to allocate from the FrameInfo
int NumBytes = (int) MFI->getStackSize();
- // Emit the correct save instruction based on the number of bytes in
- // the frame. Minimum stack frame size according to V8 ABI is:
- // 16 words for register window spill
- // 1 word for address of returned aggregate-value
- // + 6 words for passing parameters on the stack
- // ----------
- // 23 words * 4 bytes per word = 92 bytes
- NumBytes += 92;
-
- // Round up to next doubleword boundary -- a double-word boundary
- // is required by the ABI.
- NumBytes = (NumBytes + 7) & ~7;
- NumBytes = -NumBytes;
-
- if (NumBytes >= -4096) {
- BuildMI(MBB, MBBI, dl, TII.get(SP::SAVEri), SP::O6)
- .addReg(SP::O6).addImm(NumBytes);
- } else {
- // Emit this the hard way. This clobbers G1 which we always know is
- // available here.
- unsigned OffHi = (unsigned)NumBytes >> 10U;
- BuildMI(MBB, MBBI, dl, TII.get(SP::SETHIi), SP::G1).addImm(OffHi);
- // Emit G1 = G1 + I6
- BuildMI(MBB, MBBI, dl, TII.get(SP::ORri), SP::G1)
- .addReg(SP::G1).addImm(NumBytes & ((1 << 10)-1));
- BuildMI(MBB, MBBI, dl, TII.get(SP::SAVErr), SP::O6)
- .addReg(SP::O6).addReg(SP::G1);
+ unsigned SAVEri = SP::SAVEri;
+ unsigned SAVErr = SP::SAVErr;
+ if (FuncInfo->isLeafProc()) {
+ if (NumBytes == 0)
+ return;
+ SAVEri = SP::ADDri;
+ SAVErr = SP::ADDrr;
}
+
+ // The SPARC ABI is a bit odd in that it requires a reserved 92-byte
+ // (128 in v9) area in the user's stack, starting at %sp. Thus, the
+ // first part of the stack that can actually be used is located at
+ // %sp + 92.
+ //
+ // We therefore need to add that offset to the total stack size
+ // after all the stack objects are placed by
+ // PrologEpilogInserter calculateFrameObjectOffsets. However, since the stack needs to be
+ // aligned *after* the extra size is added, we need to disable
+ // calculateFrameObjectOffsets's built-in stack alignment, by having
+ // targetHandlesStackFrameRounding return true.
+
+
+ // Add the extra call frame stack size, if needed. (This is the same
+ // code as in PrologEpilogInserter, but also gets disabled by
+ // targetHandlesStackFrameRounding)
+ if (MFI->adjustsStack() && hasReservedCallFrame(MF))
+ NumBytes += MFI->getMaxCallFrameSize();
+
+ // Adds the SPARC subtarget-specific spill area to the stack
+ // size. Also ensures target-required alignment.
+ NumBytes = MF.getSubtarget<SparcSubtarget>().getAdjustedFrameSize(NumBytes);
+
+ // Finally, ensure that the size is sufficiently aligned for the
+ // data on the stack.
+ if (MFI->getMaxAlignment() > 0) {
+ NumBytes = RoundUpToAlignment(NumBytes, MFI->getMaxAlignment());
+ }
+
+ // Update stack size with corrected value.
+ MFI->setStackSize(NumBytes);
+
+ emitSPAdjustment(MF, MBB, MBBI, -NumBytes, SAVErr, SAVEri);
+
+ MachineModuleInfo &MMI = MF.getMMI();
+ unsigned regFP = RegInfo.getDwarfRegNum(SP::I6, true);
+
+ // Emit ".cfi_def_cfa_register 30".
+ unsigned CFIIndex =
+ MMI.addFrameInst(MCCFIInstruction::createDefCfaRegister(nullptr, regFP));
+ BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION))
+ .addCFIIndex(CFIIndex);
+
+ // Emit ".cfi_window_save".
+ CFIIndex = MMI.addFrameInst(MCCFIInstruction::createWindowSave(nullptr));
+ BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION))
+ .addCFIIndex(CFIIndex);
+
+ unsigned regInRA = RegInfo.getDwarfRegNum(SP::I7, true);
+ unsigned regOutRA = RegInfo.getDwarfRegNum(SP::O7, true);
+ // Emit ".cfi_register 15, 31".
+ CFIIndex = MMI.addFrameInst(
+ MCCFIInstruction::createRegister(nullptr, regOutRA, regInRA));
+ BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION))
+ .addCFIIndex(CFIIndex);
+
+ if (NeedsStackRealignment) {
+ // andn %o6, MaxAlign-1, %o6
+ int MaxAlign = MFI->getMaxAlignment();
+ BuildMI(MBB, MBBI, dl, TII.get(SP::ANDNri), SP::O6).addReg(SP::O6).addImm(MaxAlign - 1);
+ }
+}
+
+void SparcFrameLowering::
+eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator I) const {
+ if (!hasReservedCallFrame(MF)) {
+ MachineInstr &MI = *I;
+ int Size = MI.getOperand(0).getImm();
+ if (MI.getOpcode() == SP::ADJCALLSTACKDOWN)
+ Size = -Size;
+
+ if (Size)
+ emitSPAdjustment(MF, MBB, I, Size, SP::ADDrr, SP::ADDri);
+ }
+ MBB.erase(I);
}
+
void SparcFrameLowering::emitEpilogue(MachineFunction &MF,
MachineBasicBlock &MBB) const {
+ SparcMachineFunctionInfo *FuncInfo = MF.getInfo<SparcMachineFunctionInfo>();
MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
const SparcInstrInfo &TII =
- *static_cast<const SparcInstrInfo*>(MF.getTarget().getInstrInfo());
+ *static_cast<const SparcInstrInfo *>(MF.getSubtarget().getInstrInfo());
DebugLoc dl = MBBI->getDebugLoc();
assert(MBBI->getOpcode() == SP::RETL &&
"Can only put epilog before 'retl' instruction!");
- BuildMI(MBB, MBBI, dl, TII.get(SP::RESTORErr), SP::G0).addReg(SP::G0)
- .addReg(SP::G0);
+ if (!FuncInfo->isLeafProc()) {
+ BuildMI(MBB, MBBI, dl, TII.get(SP::RESTORErr), SP::G0).addReg(SP::G0)
+ .addReg(SP::G0);
+ return;
+ }
+ MachineFrameInfo *MFI = MF.getFrameInfo();
+
+ int NumBytes = (int) MFI->getStackSize();
+ if (NumBytes == 0)
+ return;
+
+ emitSPAdjustment(MF, MBB, MBBI, NumBytes, SP::ADDrr, SP::ADDri);
+}
+
+bool SparcFrameLowering::hasReservedCallFrame(const MachineFunction &MF) const {
+ // Reserve call frame if there are no variable sized objects on the stack.
+ return !MF.getFrameInfo()->hasVarSizedObjects();
+}
+
+// hasFP - Return true if the specified function should have a dedicated frame
+// pointer register. This is true if the function has variable sized allocas or
+// if frame pointer elimination is disabled.
+bool SparcFrameLowering::hasFP(const MachineFunction &MF) const {
+ const TargetRegisterInfo *RegInfo = MF.getSubtarget().getRegisterInfo();
+
+ const MachineFrameInfo *MFI = MF.getFrameInfo();
+ return MF.getTarget().Options.DisableFramePointerElim(MF) ||
+ RegInfo->needsStackRealignment(MF) ||
+ MFI->hasVarSizedObjects() ||
+ MFI->isFrameAddressTaken();
+}
+
+
+int SparcFrameLowering::getFrameIndexReference(const MachineFunction &MF, int FI,
+ unsigned &FrameReg) const {
+ const SparcSubtarget &Subtarget = MF.getSubtarget<SparcSubtarget>();
+ const MachineFrameInfo *MFI = MF.getFrameInfo();
+ const SparcRegisterInfo *RegInfo = Subtarget.getRegisterInfo();
+ const SparcMachineFunctionInfo *FuncInfo = MF.getInfo<SparcMachineFunctionInfo>();
+ bool isFixed = MFI->isFixedObjectIndex(FI);
+
+ // Addressable stack objects are accessed using neg. offsets from
+ // %fp, or positive offsets from %sp.
+ bool UseFP;
+
+ // Sparc uses FP-based references in general, even when "hasFP" is
+ // false. That function is rather a misnomer, because %fp is
+ // actually always available, unless isLeafProc.
+ if (FuncInfo->isLeafProc()) {
+ // If there's a leaf proc, all offsets need to be %sp-based,
+ // because we haven't caused %fp to actually point to our frame.
+ UseFP = false;
+ } else if (isFixed) {
+ // Otherwise, argument access should always use %fp.
+ UseFP = true;
+ } else if (RegInfo->needsStackRealignment(MF)) {
+ // If there is dynamic stack realignment, all local object
+ // references need to be via %sp, to take account of the
+ // re-alignment.
+ UseFP = false;
+ } else {
+ // Finally, default to using %fp.
+ UseFP = true;
+ }
+
+ int64_t FrameOffset = MF.getFrameInfo()->getObjectOffset(FI) +
+ Subtarget.getStackPointerBias();
+
+ if (UseFP) {
+ FrameReg = RegInfo->getFrameRegister(MF);
+ return FrameOffset;
+ } else {
+ FrameReg = SP::O6; // %sp
+ return FrameOffset + MF.getFrameInfo()->getStackSize();
+ }
+}
+
+static bool LLVM_ATTRIBUTE_UNUSED verifyLeafProcRegUse(MachineRegisterInfo *MRI)
+{
+
+ for (unsigned reg = SP::I0; reg <= SP::I7; ++reg)
+ if (!MRI->reg_nodbg_empty(reg))
+ return false;
+
+ for (unsigned reg = SP::L0; reg <= SP::L7; ++reg)
+ if (!MRI->reg_nodbg_empty(reg))
+ return false;
+
+ return true;
+}
+
+bool SparcFrameLowering::isLeafProc(MachineFunction &MF) const
+{
+
+ MachineRegisterInfo &MRI = MF.getRegInfo();
+ MachineFrameInfo *MFI = MF.getFrameInfo();
+
+ return !(MFI->hasCalls() // has calls
+ || !MRI.reg_nodbg_empty(SP::L0) // Too many registers needed
+ || !MRI.reg_nodbg_empty(SP::O6) // %SP is used
+ || hasFP(MF)); // need %FP
+}
+
+void SparcFrameLowering::remapRegsForLeafProc(MachineFunction &MF) const {
+ MachineRegisterInfo &MRI = MF.getRegInfo();
+ // Remap %i[0-7] to %o[0-7].
+ for (unsigned reg = SP::I0; reg <= SP::I7; ++reg) {
+ if (MRI.reg_nodbg_empty(reg))
+ continue;
+
+ unsigned mapped_reg = reg - SP::I0 + SP::O0;
+ assert(MRI.reg_nodbg_empty(mapped_reg));
+
+ // Replace I register with O register.
+ MRI.replaceRegWith(reg, mapped_reg);
+
+ // Also replace register pair super-registers.
+ if ((reg - SP::I0) % 2 == 0) {
+ unsigned preg = (reg - SP::I0) / 2 + SP::I0_I1;
+ unsigned mapped_preg = preg - SP::I0_I1 + SP::O0_O1;
+ MRI.replaceRegWith(preg, mapped_preg);
+ }
+ }
+
+ // Rewrite MBB's Live-ins.
+ for (MachineFunction::iterator MBB = MF.begin(), E = MF.end();
+ MBB != E; ++MBB) {
+ for (unsigned reg = SP::I0_I1; reg <= SP::I6_I7; ++reg) {
+ if (!MBB->isLiveIn(reg))
+ continue;
+ MBB->removeLiveIn(reg);
+ MBB->addLiveIn(reg - SP::I0_I1 + SP::O0_O1);
+ }
+ for (unsigned reg = SP::I0; reg <= SP::I7; ++reg) {
+ if (!MBB->isLiveIn(reg))
+ continue;
+ MBB->removeLiveIn(reg);
+ MBB->addLiveIn(reg - SP::I0 + SP::O0);
+ }
+ }
+
+ assert(verifyLeafProcRegUse(&MRI));
+#ifdef XDEBUG
+ MF.verify(0, "After LeafProc Remapping");
+#endif
+}
+
+void SparcFrameLowering::determineCalleeSaves(MachineFunction &MF,
+ BitVector &SavedRegs,
+ RegScavenger *RS) const {
+ TargetFrameLowering::determineCalleeSaves(MF, SavedRegs, RS);
+ if (!DisableLeafProc && isLeafProc(MF)) {
+ SparcMachineFunctionInfo *MFI = MF.getInfo<SparcMachineFunctionInfo>();
+ MFI->setLeafProc(true);
+
+ remapRegsForLeafProc(MF);
+ }
+
}
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