third_party/llvm-7.0/llvm/lib/Target/WebAssembly/WebAssemblyMCInstLower.cpp - SwiftShader.git - Git at Google


            
            // WebAssemblyMCInstLower.cpp - Convert WebAssembly 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

            
            /// This file contains code to lower WebAssembly MachineInstrs to their

            
            /// corresponding MCInst records.

            
            ///

            
            //===----------------------------------------------------------------------===//


            #include "WebAssemblyMCInstLower.h"

            
            #include "WebAssemblyAsmPrinter.h"

            
            #include "WebAssemblyMachineFunctionInfo.h"

            
            #include "WebAssemblyRuntimeLibcallSignatures.h"

            
            #include "WebAssemblyUtilities.h"

            
            #include "llvm/CodeGen/AsmPrinter.h"

            
            #include "llvm/CodeGen/MachineFunction.h"

            
            #include "llvm/IR/Constants.h"

            
            #include "llvm/MC/MCAsmInfo.h"

            
            #include "llvm/MC/MCContext.h"

            
            #include "llvm/MC/MCExpr.h"

            
            #include "llvm/MC/MCInst.h"

            
            #include "llvm/MC/MCSymbolWasm.h"

            
            #include "llvm/Support/ErrorHandling.h"

            
            #include "llvm/Support/raw_ostream.h"

            
            using namespace llvm;


            MCSymbol *

            
            WebAssemblyMCInstLower::GetGlobalAddressSymbol(const MachineOperand &MO) const {

            
              const GlobalValue *Global = MO.getGlobal();

            
              MCSymbolWasm *WasmSym = cast<MCSymbolWasm>(Printer.getSymbol(Global));


              if (const auto *FuncTy = dyn_cast<FunctionType>(Global->getValueType())) {

            
                const MachineFunction &MF = *MO.getParent()->getParent()->getParent();

            
                const TargetMachine &TM = MF.getTarget();

            
                const Function &CurrentFunc = MF.getFunction();


                SmallVector<wasm::ValType, 4> Returns;

            
                SmallVector<wasm::ValType, 4> Params;


                wasm::ValType iPTR =

            
                    MF.getSubtarget<WebAssemblySubtarget>().hasAddr64() ?

            
                    wasm::ValType::I64 :

            
                    wasm::ValType::I32;


                SmallVector<MVT, 4> ResultMVTs;

            
                ComputeLegalValueVTs(CurrentFunc, TM, FuncTy->getReturnType(), ResultMVTs);

            
                // WebAssembly can't currently handle returning tuples.

            
                if (ResultMVTs.size() <= 1)

            
                  for (MVT ResultMVT : ResultMVTs)

            
                    Returns.push_back(WebAssembly::toValType(ResultMVT));

            
                else

            
                  Params.push_back(iPTR);


                for (Type *Ty : FuncTy->params()) {

            
                  SmallVector<MVT, 4> ParamMVTs;

            
                  ComputeLegalValueVTs(CurrentFunc, TM, Ty, ParamMVTs);

            
                  for (MVT ParamMVT : ParamMVTs)

            
                    Params.push_back(WebAssembly::toValType(ParamMVT));

            
                }


                if (FuncTy->isVarArg())

            
                  Params.push_back(iPTR);


                WasmSym->setReturns(std::move(Returns));

            
                WasmSym->setParams(std::move(Params));

            
                WasmSym->setType(wasm::WASM_SYMBOL_TYPE_FUNCTION);

            
              }


              return WasmSym;

            
            }


            MCSymbol *WebAssemblyMCInstLower::GetExternalSymbolSymbol(

            
                const MachineOperand &MO) const {

            
              const char *Name = MO.getSymbolName();

            
              MCSymbolWasm *WasmSym =

            
                  cast<MCSymbolWasm>(Printer.GetExternalSymbolSymbol(Name));

            
              const WebAssemblySubtarget &Subtarget = Printer.getSubtarget();


              // __stack_pointer is a global variable; all other external symbols used by

            
              // CodeGen are functions.  It's OK to hardcode knowledge of specific symbols

            
              // here; this method is precisely there for fetching the signatures of known

            
              // Clang-provided symbols.

            
              if (strcmp(Name, "__stack_pointer") == 0) {

            
                WasmSym->setType(wasm::WASM_SYMBOL_TYPE_GLOBAL);

            
                WasmSym->setGlobalType(wasm::WasmGlobalType{

            
                    uint8_t(Subtarget.hasAddr64() ? wasm::WASM_TYPE_I64

            
                                                  : wasm::WASM_TYPE_I32),

            
                    true});

            
                return WasmSym;

            
              }


              SmallVector<wasm::ValType, 4> Returns;

            
              SmallVector<wasm::ValType, 4> Params;

            
              GetSignature(Subtarget, Name, Returns, Params);


              WasmSym->setReturns(std::move(Returns));

            
              WasmSym->setParams(std::move(Params));

            
              WasmSym->setType(wasm::WASM_SYMBOL_TYPE_FUNCTION);


              return WasmSym;

            
            }


            MCOperand WebAssemblyMCInstLower::LowerSymbolOperand(MCSymbol *Sym,

            
                                                                 int64_t Offset,

            
                                                                 bool IsFunc) const {

            
              MCSymbolRefExpr::VariantKind VK =

            
                  IsFunc ? MCSymbolRefExpr::VK_WebAssembly_FUNCTION

            
                         : MCSymbolRefExpr::VK_None;


              const MCExpr *Expr = MCSymbolRefExpr::create(Sym, VK, Ctx);


              if (Offset != 0) {

            
                if (IsFunc)

            
                  report_fatal_error("Function addresses with offsets not supported");

            
                Expr =

            
                    MCBinaryExpr::createAdd(Expr, MCConstantExpr::create(Offset, Ctx), Ctx);

            
              }


              return MCOperand::createExpr(Expr);

            
            }


            // Return the WebAssembly type associated with the given register class.

            
            static wasm::ValType getType(const TargetRegisterClass *RC) {

            
              if (RC == &WebAssembly::I32RegClass)

            
                return wasm::ValType::I32;

            
              if (RC == &WebAssembly::I64RegClass)

            
                return wasm::ValType::I64;

            
              if (RC == &WebAssembly::F32RegClass)

            
                return wasm::ValType::F32;

            
              if (RC == &WebAssembly::F64RegClass)

            
                return wasm::ValType::F64;

            
              llvm_unreachable("Unexpected register class");

            
            }


            void WebAssemblyMCInstLower::Lower(const MachineInstr *MI,

            
                                               MCInst &OutMI) const {

            
              OutMI.setOpcode(MI->getOpcode());


              const MCInstrDesc &Desc = MI->getDesc();

            
              for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {

            
                const MachineOperand &MO = MI->getOperand(i);


                MCOperand MCOp;

            
                switch (MO.getType()) {

            
                default:

            
                  MI->print(errs());

            
                  llvm_unreachable("unknown operand type");

            
                case MachineOperand::MO_MachineBasicBlock:

            
                  MI->print(errs());

            
                  llvm_unreachable("MachineBasicBlock operand should have been rewritten");

            
                case MachineOperand::MO_Register: {

            
                  // Ignore all implicit register operands.

            
                  if (MO.isImplicit())

            
                    continue;

            
                  const WebAssemblyFunctionInfo &MFI =

            
                      *MI->getParent()->getParent()->getInfo<WebAssemblyFunctionInfo>();

            
                  unsigned WAReg = MFI.getWAReg(MO.getReg());

            
                  MCOp = MCOperand::createReg(WAReg);

            
                  break;

            
                }

            
                case MachineOperand::MO_Immediate:

            
                  if (i < Desc.NumOperands) {

            
                    const MCOperandInfo &Info = Desc.OpInfo[i];

            
                    if (Info.OperandType == WebAssembly::OPERAND_TYPEINDEX) {

            
                      MCSymbol *Sym = Printer.createTempSymbol("typeindex");


                      SmallVector<wasm::ValType, 4> Returns;

            
                      SmallVector<wasm::ValType, 4> Params;


                      const MachineRegisterInfo &MRI =

            
                          MI->getParent()->getParent()->getRegInfo();

            
                      for (const MachineOperand &MO : MI->defs())

            
                        Returns.push_back(getType(MRI.getRegClass(MO.getReg())));

            
                      for (const MachineOperand &MO : MI->explicit_uses())

            
                        if (MO.isReg())

            
                          Params.push_back(getType(MRI.getRegClass(MO.getReg())));


                      // call_indirect instructions have a callee operand at the end which

            
                      // doesn't count as a param.

            
                      if (WebAssembly::isCallIndirect(*MI))

            
                        Params.pop_back();


                      MCSymbolWasm *WasmSym = cast<MCSymbolWasm>(Sym);

            
                      WasmSym->setReturns(std::move(Returns));

            
                      WasmSym->setParams(std::move(Params));

            
                      WasmSym->setType(wasm::WASM_SYMBOL_TYPE_FUNCTION);


                      const MCExpr *Expr = MCSymbolRefExpr::create(

            
                          WasmSym, MCSymbolRefExpr::VK_WebAssembly_TYPEINDEX, Ctx);

            
                      MCOp = MCOperand::createExpr(Expr);

            
                      break;

            
                    }

            
                  }

            
                  MCOp = MCOperand::createImm(MO.getImm());

            
                  break;

            
                case MachineOperand::MO_FPImmediate: {

            
                  // TODO: MC converts all floating point immediate operands to double.

            
                  // This is fine for numeric values, but may cause NaNs to change bits.

            
                  const ConstantFP *Imm = MO.getFPImm();

            
                  if (Imm->getType()->isFloatTy())

            
                    MCOp = MCOperand::createFPImm(Imm->getValueAPF().convertToFloat());

            
                  else if (Imm->getType()->isDoubleTy())

            
                    MCOp = MCOperand::createFPImm(Imm->getValueAPF().convertToDouble());

            
                  else

            
                    llvm_unreachable("unknown floating point immediate type");

            
                  break;

            
                }

            
                case MachineOperand::MO_GlobalAddress:

            
                  assert(MO.getTargetFlags() == 0 &&

            
                         "WebAssembly does not use target flags on GlobalAddresses");

            
                  MCOp = LowerSymbolOperand(GetGlobalAddressSymbol(MO), MO.getOffset(),

            
                                            MO.getGlobal()->getValueType()->isFunctionTy());

            
                  break;

            
                case MachineOperand::MO_ExternalSymbol:

            
                  // The target flag indicates whether this is a symbol for a

            
                  // variable or a function.

            
                  assert((MO.getTargetFlags() & -2) == 0 &&

            
                         "WebAssembly uses only one target flag bit on ExternalSymbols");

            
                  MCOp = LowerSymbolOperand(GetExternalSymbolSymbol(MO), /*Offset=*/0,

            
                                            MO.getTargetFlags() & 1);

            
                  break;

            
                }


                OutMI.addOperand(MCOp);

            
              }

            
            }
	// WebAssemblyMCInstLower.cpp - Convert WebAssembly 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
	/// This file contains code to lower WebAssembly MachineInstrs to their
	/// corresponding MCInst records.
	///
	//===----------------------------------------------------------------------===//

	#include "WebAssemblyMCInstLower.h"
	#include "WebAssemblyAsmPrinter.h"
	#include "WebAssemblyMachineFunctionInfo.h"
	#include "WebAssemblyRuntimeLibcallSignatures.h"
	#include "WebAssemblyUtilities.h"
	#include "llvm/CodeGen/AsmPrinter.h"
	#include "llvm/CodeGen/MachineFunction.h"
	#include "llvm/IR/Constants.h"
	#include "llvm/MC/MCAsmInfo.h"
	#include "llvm/MC/MCContext.h"
	#include "llvm/MC/MCExpr.h"
	#include "llvm/MC/MCInst.h"
	#include "llvm/MC/MCSymbolWasm.h"
	#include "llvm/Support/ErrorHandling.h"
	#include "llvm/Support/raw_ostream.h"
	using namespace llvm;

	MCSymbol *
	WebAssemblyMCInstLower::GetGlobalAddressSymbol(const MachineOperand &MO) const {
	const GlobalValue *Global = MO.getGlobal();
	MCSymbolWasm *WasmSym = cast<MCSymbolWasm>(Printer.getSymbol(Global));

	if (const auto *FuncTy = dyn_cast<FunctionType>(Global->getValueType())) {
	const MachineFunction &MF = *MO.getParent()->getParent()->getParent();
	const TargetMachine &TM = MF.getTarget();
	const Function &CurrentFunc = MF.getFunction();

	SmallVector<wasm::ValType, 4> Returns;
	SmallVector<wasm::ValType, 4> Params;

	wasm::ValType iPTR =
	MF.getSubtarget<WebAssemblySubtarget>().hasAddr64() ?
	wasm::ValType::I64 :
	wasm::ValType::I32;

	SmallVector<MVT, 4> ResultMVTs;
	ComputeLegalValueVTs(CurrentFunc, TM, FuncTy->getReturnType(), ResultMVTs);
	// WebAssembly can't currently handle returning tuples.
	if (ResultMVTs.size() <= 1)
	for (MVT ResultMVT : ResultMVTs)
	Returns.push_back(WebAssembly::toValType(ResultMVT));
	else
	Params.push_back(iPTR);

	for (Type *Ty : FuncTy->params()) {
	SmallVector<MVT, 4> ParamMVTs;
	ComputeLegalValueVTs(CurrentFunc, TM, Ty, ParamMVTs);
	for (MVT ParamMVT : ParamMVTs)
	Params.push_back(WebAssembly::toValType(ParamMVT));
	}

	if (FuncTy->isVarArg())
	Params.push_back(iPTR);

	WasmSym->setReturns(std::move(Returns));
	WasmSym->setParams(std::move(Params));
	WasmSym->setType(wasm::WASM_SYMBOL_TYPE_FUNCTION);
	}

	return WasmSym;
	}

	MCSymbol *WebAssemblyMCInstLower::GetExternalSymbolSymbol(
	const MachineOperand &MO) const {
	const char *Name = MO.getSymbolName();
	MCSymbolWasm *WasmSym =
	cast<MCSymbolWasm>(Printer.GetExternalSymbolSymbol(Name));
	const WebAssemblySubtarget &Subtarget = Printer.getSubtarget();

	// __stack_pointer is a global variable; all other external symbols used by
	// CodeGen are functions. It's OK to hardcode knowledge of specific symbols
	// here; this method is precisely there for fetching the signatures of known
	// Clang-provided symbols.
	if (strcmp(Name, "__stack_pointer") == 0) {
	WasmSym->setType(wasm::WASM_SYMBOL_TYPE_GLOBAL);
	WasmSym->setGlobalType(wasm::WasmGlobalType{
	uint8_t(Subtarget.hasAddr64() ? wasm::WASM_TYPE_I64
	: wasm::WASM_TYPE_I32),
	true});
	return WasmSym;
	}

	SmallVector<wasm::ValType, 4> Returns;
	SmallVector<wasm::ValType, 4> Params;
	GetSignature(Subtarget, Name, Returns, Params);

	WasmSym->setReturns(std::move(Returns));
	WasmSym->setParams(std::move(Params));
	WasmSym->setType(wasm::WASM_SYMBOL_TYPE_FUNCTION);

	return WasmSym;
	}

	MCOperand WebAssemblyMCInstLower::LowerSymbolOperand(MCSymbol *Sym,
	int64_t Offset,
	bool IsFunc) const {
	MCSymbolRefExpr::VariantKind VK =
	IsFunc ? MCSymbolRefExpr::VK_WebAssembly_FUNCTION
	: MCSymbolRefExpr::VK_None;

	const MCExpr *Expr = MCSymbolRefExpr::create(Sym, VK, Ctx);

	if (Offset != 0) {
	if (IsFunc)
	report_fatal_error("Function addresses with offsets not supported");
	Expr =
	MCBinaryExpr::createAdd(Expr, MCConstantExpr::create(Offset, Ctx), Ctx);
	}

	return MCOperand::createExpr(Expr);
	}

	// Return the WebAssembly type associated with the given register class.
	static wasm::ValType getType(const TargetRegisterClass *RC) {
	if (RC == &WebAssembly::I32RegClass)
	return wasm::ValType::I32;
	if (RC == &WebAssembly::I64RegClass)
	return wasm::ValType::I64;
	if (RC == &WebAssembly::F32RegClass)
	return wasm::ValType::F32;
	if (RC == &WebAssembly::F64RegClass)
	return wasm::ValType::F64;
	llvm_unreachable("Unexpected register class");
	}

	void WebAssemblyMCInstLower::Lower(const MachineInstr *MI,
	MCInst &OutMI) const {
	OutMI.setOpcode(MI->getOpcode());

	const MCInstrDesc &Desc = MI->getDesc();
	for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
	const MachineOperand &MO = MI->getOperand(i);

	MCOperand MCOp;
	switch (MO.getType()) {
	default:
	MI->print(errs());
	llvm_unreachable("unknown operand type");
	case MachineOperand::MO_MachineBasicBlock:
	MI->print(errs());
	llvm_unreachable("MachineBasicBlock operand should have been rewritten");
	case MachineOperand::MO_Register: {
	// Ignore all implicit register operands.
	if (MO.isImplicit())
	continue;
	const WebAssemblyFunctionInfo &MFI =
	*MI->getParent()->getParent()->getInfo<WebAssemblyFunctionInfo>();
	unsigned WAReg = MFI.getWAReg(MO.getReg());
	MCOp = MCOperand::createReg(WAReg);
	break;
	}
	case MachineOperand::MO_Immediate:
	if (i < Desc.NumOperands) {
	const MCOperandInfo &Info = Desc.OpInfo[i];
	if (Info.OperandType == WebAssembly::OPERAND_TYPEINDEX) {
	MCSymbol *Sym = Printer.createTempSymbol("typeindex");

	SmallVector<wasm::ValType, 4> Returns;
	SmallVector<wasm::ValType, 4> Params;

	const MachineRegisterInfo &MRI =
	MI->getParent()->getParent()->getRegInfo();
	for (const MachineOperand &MO : MI->defs())
	Returns.push_back(getType(MRI.getRegClass(MO.getReg())));
	for (const MachineOperand &MO : MI->explicit_uses())
	if (MO.isReg())
	Params.push_back(getType(MRI.getRegClass(MO.getReg())));

	// call_indirect instructions have a callee operand at the end which
	// doesn't count as a param.
	if (WebAssembly::isCallIndirect(*MI))
	Params.pop_back();

	MCSymbolWasm *WasmSym = cast<MCSymbolWasm>(Sym);
	WasmSym->setReturns(std::move(Returns));
	WasmSym->setParams(std::move(Params));
	WasmSym->setType(wasm::WASM_SYMBOL_TYPE_FUNCTION);

	const MCExpr *Expr = MCSymbolRefExpr::create(
	WasmSym, MCSymbolRefExpr::VK_WebAssembly_TYPEINDEX, Ctx);
	MCOp = MCOperand::createExpr(Expr);
	break;
	}
	}
	MCOp = MCOperand::createImm(MO.getImm());
	break;
	case MachineOperand::MO_FPImmediate: {
	// TODO: MC converts all floating point immediate operands to double.
	// This is fine for numeric values, but may cause NaNs to change bits.
	const ConstantFP *Imm = MO.getFPImm();
	if (Imm->getType()->isFloatTy())
	MCOp = MCOperand::createFPImm(Imm->getValueAPF().convertToFloat());
	else if (Imm->getType()->isDoubleTy())
	MCOp = MCOperand::createFPImm(Imm->getValueAPF().convertToDouble());
	else
	llvm_unreachable("unknown floating point immediate type");
	break;
	}
	case MachineOperand::MO_GlobalAddress:
	assert(MO.getTargetFlags() == 0 &&
	"WebAssembly does not use target flags on GlobalAddresses");
	MCOp = LowerSymbolOperand(GetGlobalAddressSymbol(MO), MO.getOffset(),
	MO.getGlobal()->getValueType()->isFunctionTy());
	break;
	case MachineOperand::MO_ExternalSymbol:
	// The target flag indicates whether this is a symbol for a
	// variable or a function.
	assert((MO.getTargetFlags() & -2) == 0 &&
	"WebAssembly uses only one target flag bit on ExternalSymbols");
	MCOp = LowerSymbolOperand(GetExternalSymbolSymbol(MO), /Offset=/0,
	MO.getTargetFlags() & 1);
	break;
	}

	OutMI.addOperand(MCOp);
	}
	}