WebAssemblyUtilities.h

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//===-- WebAssemblyUtilities - WebAssembly Utility Functions ---*- C++ -*-====//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
///
/// \file
/// This file contains the declaration of the WebAssembly-specific
/// utility functions.
///
//===----------------------------------------------------------------------===//
 
#ifndef LLVM_LIB_TARGET_WEBASSEMBLY_UTILS_WEBASSEMBLYUTILITIES_H
#define LLVM_LIB_TARGET_WEBASSEMBLY_UTILS_WEBASSEMBLYUTILITIES_H
 
#include "llvm/IR/DerivedTypes.h"
#include "llvm/Support/CommandLine.h"
 
namespace llvm {
 
class MachineBasicBlock;
class MachineInstr;
class MachineOperand;
class MCContext;
class MCSymbolWasm;
class WebAssemblyFunctionInfo;
class WebAssemblySubtarget;
 
namespace WebAssembly {
 
enum WasmAddressSpace : unsigned {
  // Default address space, for pointers to linear memory (stack, heap, data).
  WASM_ADDRESS_SPACE_DEFAULT = 0,
  // A non-integral address space for pointers to named objects outside of
  // linear memory: WebAssembly globals or WebAssembly locals.  Loads and stores
  // to these pointers are lowered to global.get / global.set or local.get /
  // local.set, as appropriate.
  WASM_ADDRESS_SPACE_VAR = 1,
  // A non-integral address space for externref values
  WASM_ADDRESS_SPACE_EXTERNREF = 10,
  // A non-integral address space for funcref values
  WASM_ADDRESS_SPACE_FUNCREF = 20,
};
 
inline bool isDefaultAddressSpace(unsigned AS) {
  return AS == WASM_ADDRESS_SPACE_DEFAULT;
}
inline bool isWasmVarAddressSpace(unsigned AS) {
  return AS == WASM_ADDRESS_SPACE_VAR;
}
inline bool isValidAddressSpace(unsigned AS) {
  return isDefaultAddressSpace(AS) || isWasmVarAddressSpace(AS);
}
inline bool isFuncrefType(const Type *Ty) {
  return isa<PointerType>(Ty) &&
         Ty->getPointerAddressSpace() ==
             WasmAddressSpace::WASM_ADDRESS_SPACE_FUNCREF;
}
inline bool isExternrefType(const Type *Ty) {
  return isa<PointerType>(Ty) &&
         Ty->getPointerAddressSpace() ==
             WasmAddressSpace::WASM_ADDRESS_SPACE_EXTERNREF;
}
inline bool isRefType(const Type *Ty) {
  return isFuncrefType(Ty) || isExternrefType(Ty);
}
 
bool isChild(const MachineInstr &MI, const WebAssemblyFunctionInfo &MFI);
bool mayThrow(const MachineInstr &MI);
 
// Exception handling / setjmp-longjmp handling command-line options
extern cl::opt<bool> WasmEnableEmEH;   // asm.js-style EH
extern cl::opt<bool> WasmEnableEmSjLj; // asm.js-style SjLJ
extern cl::opt<bool> WasmEnableEH;     // EH using Wasm EH instructions
extern cl::opt<bool> WasmEnableSjLj;   // SjLj using Wasm EH instructions
 
// Exception-related function names
extern const char *const ClangCallTerminateFn;
extern const char *const CxaBeginCatchFn;
extern const char *const CxaRethrowFn;
extern const char *const StdTerminateFn;
extern const char *const PersonalityWrapperFn;
 
/// Returns the operand number of a callee, assuming the argument is a call
/// instruction.
const MachineOperand &getCalleeOp(const MachineInstr &MI);
 
/// Returns the __indirect_function_table, for use in call_indirect and in
/// function bitcasts.
MCSymbolWasm *
getOrCreateFunctionTableSymbol(MCContext &Ctx,
                               const WebAssemblySubtarget *Subtarget);
 
/// Returns the __funcref_call_table, for use in funcref calls when lowered to
/// table.set + call_indirect.
MCSymbolWasm *
getOrCreateFuncrefCallTableSymbol(MCContext &Ctx,
                                  const WebAssemblySubtarget *Subtarget);
 
/// Find a catch instruction from an EH pad. Returns null if no catch
/// instruction found or the catch is in an invalid location.
MachineInstr *findCatch(MachineBasicBlock *EHPad);
 
} // end namespace WebAssembly
 
} // end namespace llvm
 
#endif