third_party/llvm-7.0/llvm/lib/Target/WebAssembly/WebAssemblyMCInstLower.cpp - platform/external/swiftshader - 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);
	}
	}