forked from OSchip/llvm-project
68 lines
2.4 KiB
C++
68 lines
2.4 KiB
C++
//===-- WebAssemblyUtilities.cpp - WebAssembly Utility Functions ----------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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///
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/// \file
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/// This file implements several utility functions for WebAssembly.
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///
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//===----------------------------------------------------------------------===//
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#include "WebAssemblyUtilities.h"
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#include "WebAssemblyMachineFunctionInfo.h"
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#include "llvm/CodeGen/MachineInstr.h"
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#include "llvm/CodeGen/MachineLoopInfo.h"
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using namespace llvm;
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const char *const WebAssembly::ClangCallTerminateFn = "__clang_call_terminate";
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const char *const WebAssembly::CxaBeginCatchFn = "__cxa_begin_catch";
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const char *const WebAssembly::CxaRethrowFn = "__cxa_rethrow";
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const char *const WebAssembly::StdTerminateFn = "_ZSt9terminatev";
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const char *const WebAssembly::PersonalityWrapperFn =
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"_Unwind_Wasm_CallPersonality";
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/// Test whether MI is a child of some other node in an expression tree.
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bool WebAssembly::isChild(const MachineInstr &MI,
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const WebAssemblyFunctionInfo &MFI) {
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if (MI.getNumOperands() == 0)
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return false;
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const MachineOperand &MO = MI.getOperand(0);
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if (!MO.isReg() || MO.isImplicit() || !MO.isDef())
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return false;
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Register Reg = MO.getReg();
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return Register::isVirtualRegister(Reg) && MFI.isVRegStackified(Reg);
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}
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bool WebAssembly::mayThrow(const MachineInstr &MI) {
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switch (MI.getOpcode()) {
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case WebAssembly::THROW:
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case WebAssembly::THROW_S:
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case WebAssembly::RETHROW:
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case WebAssembly::RETHROW_S:
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return true;
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}
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if (isCallIndirect(MI.getOpcode()))
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return true;
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if (!MI.isCall())
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return false;
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const MachineOperand &MO = MI.getOperand(getCalleeOpNo(MI.getOpcode()));
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assert(MO.isGlobal());
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const auto *F = dyn_cast<Function>(MO.getGlobal());
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if (!F)
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return true;
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if (F->doesNotThrow())
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return false;
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// These functions never throw
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if (F->getName() == CxaBeginCatchFn || F->getName() == PersonalityWrapperFn ||
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F->getName() == ClangCallTerminateFn || F->getName() == StdTerminateFn)
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return false;
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// TODO Can we exclude call instructions that are marked as 'nounwind' in the
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// original LLVm IR? (Even when the callee may throw)
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return true;
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}
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