Imported Upstream version 6.0.0.172

Former-commit-id: f3cc9b82f3e5bd8f0fd3ebc098f789556b44e9cd

external/llvm/lib/Target/AMDGPU/AMDGPUMCInstLower.cpp

@@ -0,0 +1,294 @@
+//===- AMDGPUMCInstLower.cpp - Lower AMDGPU MachineInstr to an MCInst -----===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+/// \file
+/// \brief Code to lower AMDGPU MachineInstrs to their corresponding MCInst.
+//
+//===----------------------------------------------------------------------===//
+//
+
+#include "AMDGPUMCInstLower.h"
+#include "AMDGPUAsmPrinter.h"
+#include "AMDGPUSubtarget.h"
+#include "AMDGPUTargetMachine.h"
+#include "InstPrinter/AMDGPUInstPrinter.h"
+#include "SIInstrInfo.h"
+#include "llvm/CodeGen/MachineBasicBlock.h"
+#include "llvm/CodeGen/MachineInstr.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/GlobalVariable.h"
+#include "llvm/MC/MCCodeEmitter.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCInst.h"
+#include "llvm/MC/MCObjectStreamer.h"
+#include "llvm/MC/MCStreamer.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/Format.h"
+#include <algorithm>
+
+using namespace llvm;
+
+#include "AMDGPUGenMCPseudoLowering.inc"
+
+AMDGPUMCInstLower::AMDGPUMCInstLower(MCContext &ctx, const AMDGPUSubtarget &st,
+                                     const AsmPrinter &ap):
+  Ctx(ctx), ST(st), AP(ap) { }
+
+static MCSymbolRefExpr::VariantKind getVariantKind(unsigned MOFlags) {
+  switch (MOFlags) {
+  default:
+    return MCSymbolRefExpr::VK_None;
+  case SIInstrInfo::MO_GOTPCREL:
+    return MCSymbolRefExpr::VK_GOTPCREL;
+  case SIInstrInfo::MO_GOTPCREL32_LO:
+    return MCSymbolRefExpr::VK_AMDGPU_GOTPCREL32_LO;
+  case SIInstrInfo::MO_GOTPCREL32_HI:
+    return MCSymbolRefExpr::VK_AMDGPU_GOTPCREL32_HI;
+  case SIInstrInfo::MO_REL32_LO:
+    return MCSymbolRefExpr::VK_AMDGPU_REL32_LO;
+  case SIInstrInfo::MO_REL32_HI:
+    return MCSymbolRefExpr::VK_AMDGPU_REL32_HI;
+  }
+}
+
+const MCExpr *AMDGPUMCInstLower::getLongBranchBlockExpr(
+  const MachineBasicBlock &SrcBB,
+  const MachineOperand &MO) const {
+  const MCExpr *DestBBSym
+    = MCSymbolRefExpr::create(MO.getMBB()->getSymbol(), Ctx);
+  const MCExpr *SrcBBSym = MCSymbolRefExpr::create(SrcBB.getSymbol(), Ctx);
+
+  assert(SrcBB.front().getOpcode() == AMDGPU::S_GETPC_B64 &&
+         ST.getInstrInfo()->get(AMDGPU::S_GETPC_B64).Size == 4);
+
+  // s_getpc_b64 returns the address of next instruction.
+  const MCConstantExpr *One = MCConstantExpr::create(4, Ctx);
+  SrcBBSym = MCBinaryExpr::createAdd(SrcBBSym, One, Ctx);
+
+  if (MO.getTargetFlags() == AMDGPU::TF_LONG_BRANCH_FORWARD)
+    return MCBinaryExpr::createSub(DestBBSym, SrcBBSym, Ctx);
+
+  assert(MO.getTargetFlags() == AMDGPU::TF_LONG_BRANCH_BACKWARD);
+  return MCBinaryExpr::createSub(SrcBBSym, DestBBSym, Ctx);
+}
+
+bool AMDGPUMCInstLower::lowerOperand(const MachineOperand &MO,
+                                     MCOperand &MCOp) const {
+  switch (MO.getType()) {
+  default:
+    llvm_unreachable("unknown operand type");
+  case MachineOperand::MO_Immediate:
+    MCOp = MCOperand::createImm(MO.getImm());
+    return true;
+  case MachineOperand::MO_Register:
+    MCOp = MCOperand::createReg(AMDGPU::getMCReg(MO.getReg(), ST));
+    return true;
+  case MachineOperand::MO_MachineBasicBlock: {
+    if (MO.getTargetFlags() != 0) {
+      MCOp = MCOperand::createExpr(
+        getLongBranchBlockExpr(*MO.getParent()->getParent(), MO));
+    } else {
+      MCOp = MCOperand::createExpr(
+        MCSymbolRefExpr::create(MO.getMBB()->getSymbol(), Ctx));
+    }
+
+    return true;
+  }
+  case MachineOperand::MO_GlobalAddress: {
+    const GlobalValue *GV = MO.getGlobal();
+    SmallString<128> SymbolName;
+    AP.getNameWithPrefix(SymbolName, GV);
+    MCSymbol *Sym = Ctx.getOrCreateSymbol(SymbolName);
+    const MCExpr *SymExpr =
+      MCSymbolRefExpr::create(Sym, getVariantKind(MO.getTargetFlags()),Ctx);
+    const MCExpr *Expr = MCBinaryExpr::createAdd(SymExpr,
+      MCConstantExpr::create(MO.getOffset(), Ctx), Ctx);
+    MCOp = MCOperand::createExpr(Expr);
+    return true;
+  }
+  case MachineOperand::MO_ExternalSymbol: {
+    MCSymbol *Sym = Ctx.getOrCreateSymbol(StringRef(MO.getSymbolName()));
+    Sym->setExternal(true);
+    const MCSymbolRefExpr *Expr = MCSymbolRefExpr::create(Sym, Ctx);
+    MCOp = MCOperand::createExpr(Expr);
+    return true;
+  }
+  case MachineOperand::MO_RegisterMask:
+    // Regmasks are like implicit defs.
+    return false;
+  }
+}
+
+void AMDGPUMCInstLower::lower(const MachineInstr *MI, MCInst &OutMI) const {
+  unsigned Opcode = MI->getOpcode();
+  const auto *TII = ST.getInstrInfo();
+
+  // FIXME: Should be able to handle this with emitPseudoExpansionLowering. We
+  // need to select it to the subtarget specific version, and there's no way to
+  // do that with a single pseudo source operation.
+  if (Opcode == AMDGPU::S_SETPC_B64_return)
+    Opcode = AMDGPU::S_SETPC_B64;
+  else if (Opcode == AMDGPU::SI_CALL) {
+    // SI_CALL is just S_SWAPPC_B64 with an additional operand to track the
+    // called function (which we need to remove here).
+    OutMI.setOpcode(TII->pseudoToMCOpcode(AMDGPU::S_SWAPPC_B64));
+    MCOperand Dest, Src;
+    lowerOperand(MI->getOperand(0), Dest);
+    lowerOperand(MI->getOperand(1), Src);
+    OutMI.addOperand(Dest);
+    OutMI.addOperand(Src);
+    return;
+  } else if (Opcode == AMDGPU::SI_TCRETURN) {
+    // TODO: How to use branch immediate and avoid register+add?
+    Opcode = AMDGPU::S_SETPC_B64;
+  }
+
+  int MCOpcode = TII->pseudoToMCOpcode(Opcode);
+  if (MCOpcode == -1) {
+    LLVMContext &C = MI->getParent()->getParent()->getFunction().getContext();
+    C.emitError("AMDGPUMCInstLower::lower - Pseudo instruction doesn't have "
+                "a target-specific version: " + Twine(MI->getOpcode()));
+  }
+
+  OutMI.setOpcode(MCOpcode);
+
+  for (const MachineOperand &MO : MI->explicit_operands()) {
+    MCOperand MCOp;
+    lowerOperand(MO, MCOp);
+    OutMI.addOperand(MCOp);
+  }
+}
+
+bool AMDGPUAsmPrinter::lowerOperand(const MachineOperand &MO,
+                                    MCOperand &MCOp) const {
+  const AMDGPUSubtarget &STI = MF->getSubtarget<AMDGPUSubtarget>();
+  AMDGPUMCInstLower MCInstLowering(OutContext, STI, *this);
+  return MCInstLowering.lowerOperand(MO, MCOp);
+}
+
+const MCExpr *AMDGPUAsmPrinter::lowerConstant(const Constant *CV) {
+  // TargetMachine does not support llvm-style cast. Use C++-style cast.
+  // This is safe since TM is always of type AMDGPUTargetMachine or its
+  // derived class.
+  auto *AT = static_cast<AMDGPUTargetMachine*>(&TM);
+  auto *CE = dyn_cast<ConstantExpr>(CV);
+
+  // Lower null pointers in private and local address space.
+  // Clang generates addrspacecast for null pointers in private and local
+  // address space, which needs to be lowered.
+  if (CE && CE->getOpcode() == Instruction::AddrSpaceCast) {
+    auto Op = CE->getOperand(0);
+    auto SrcAddr = Op->getType()->getPointerAddressSpace();
+    if (Op->isNullValue() && AT->getNullPointerValue(SrcAddr) == 0) {
+      auto DstAddr = CE->getType()->getPointerAddressSpace();
+      return MCConstantExpr::create(AT->getNullPointerValue(DstAddr),
+        OutContext);
+    }
+  }
+  return AsmPrinter::lowerConstant(CV);
+}
+
+void AMDGPUAsmPrinter::EmitInstruction(const MachineInstr *MI) {
+  if (emitPseudoExpansionLowering(*OutStreamer, MI))
+    return;
+
+  const AMDGPUSubtarget &STI = MF->getSubtarget<AMDGPUSubtarget>();
+  AMDGPUMCInstLower MCInstLowering(OutContext, STI, *this);
+
+  StringRef Err;
+  if (!STI.getInstrInfo()->verifyInstruction(*MI, Err)) {
+    LLVMContext &C = MI->getParent()->getParent()->getFunction().getContext();
+    C.emitError("Illegal instruction detected: " + Err);
+    MI->print(errs());
+  }
+
+  if (MI->isBundle()) {
+    const MachineBasicBlock *MBB = MI->getParent();
+    MachineBasicBlock::const_instr_iterator I = ++MI->getIterator();
+    while (I != MBB->instr_end() && I->isInsideBundle()) {
+      EmitInstruction(&*I);
+      ++I;
+    }
+  } else {
+    // We don't want SI_MASK_BRANCH/SI_RETURN_TO_EPILOG encoded. They are
+    // placeholder terminator instructions and should only be printed as
+    // comments.
+    if (MI->getOpcode() == AMDGPU::SI_MASK_BRANCH) {
+      if (isVerbose()) {
+        SmallVector<char, 16> BBStr;
+        raw_svector_ostream Str(BBStr);
+
+        const MachineBasicBlock *MBB = MI->getOperand(0).getMBB();
+        const MCSymbolRefExpr *Expr
+          = MCSymbolRefExpr::create(MBB->getSymbol(), OutContext);
+        Expr->print(Str, MAI);
+        OutStreamer->emitRawComment(Twine(" mask branch ") + BBStr);
+      }
+
+      return;
+    }
+
+    if (MI->getOpcode() == AMDGPU::SI_RETURN_TO_EPILOG) {
+      if (isVerbose())
+        OutStreamer->emitRawComment(" return to shader part epilog");
+      return;
+    }
+
+    if (MI->getOpcode() == AMDGPU::WAVE_BARRIER) {
+      if (isVerbose())
+        OutStreamer->emitRawComment(" wave barrier");
+      return;
+    }
+
+    if (MI->getOpcode() == AMDGPU::SI_MASKED_UNREACHABLE) {
+      if (isVerbose())
+        OutStreamer->emitRawComment(" divergent unreachable");
+      return;
+    }
+
+    MCInst TmpInst;
+    MCInstLowering.lower(MI, TmpInst);
+    EmitToStreamer(*OutStreamer, TmpInst);
+
+    if (STI.dumpCode()) {
+      // Disassemble instruction/operands to text.
+      DisasmLines.resize(DisasmLines.size() + 1);
+      std::string &DisasmLine = DisasmLines.back();
+      raw_string_ostream DisasmStream(DisasmLine);
+
+      AMDGPUInstPrinter InstPrinter(*TM.getMCAsmInfo(),
+                                    *STI.getInstrInfo(),
+                                    *STI.getRegisterInfo());
+      InstPrinter.printInst(&TmpInst, DisasmStream, StringRef(), STI);
+
+      // Disassemble instruction/operands to hex representation.
+      SmallVector<MCFixup, 4> Fixups;
+      SmallVector<char, 16> CodeBytes;
+      raw_svector_ostream CodeStream(CodeBytes);
+
+      auto &ObjStreamer = static_cast<MCObjectStreamer&>(*OutStreamer);
+      MCCodeEmitter &InstEmitter = ObjStreamer.getAssembler().getEmitter();
+      InstEmitter.encodeInstruction(TmpInst, CodeStream, Fixups,
+                                    MF->getSubtarget<MCSubtargetInfo>());
+      HexLines.resize(HexLines.size() + 1);
+      std::string &HexLine = HexLines.back();
+      raw_string_ostream HexStream(HexLine);
+
+      for (size_t i = 0; i < CodeBytes.size(); i += 4) {
+        unsigned int CodeDWord = *(unsigned int *)&CodeBytes[i];
+        HexStream << format("%s%08X", (i > 0 ? " " : ""), CodeDWord);
+      }
+
+      DisasmStream.flush();
+      DisasmLineMaxLen = std::max(DisasmLineMaxLen, DisasmLine.size());
+    }
+  }
+}