649aba93a2
Summary: This reverts commit 3ef169e586f4d14efe690c23c878d5aa92a80eb5. The purpose of this commit was to allow stack machines to perform instruction selection for instructions with variadic defs. However, MachineInstrs fundamentally cannot support variadic defs right now, so this change does not turn out to be useful. Depends on D73927. Reviewers: aheejin Subscribers: dschuff, sbc100, jgravelle-google, hiraditya, sunfish, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D73928
82 lines
2.9 KiB
C++
82 lines
2.9 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() || MO.isSymbol());
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if (MO.isSymbol()) {
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// Some intrinsics are lowered to calls to external symbols, which are then
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// lowered to calls to library functions. Most of libcalls don't throw, but
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// we only list some of them here now.
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// TODO Consider adding 'nounwind' info in TargetLowering::CallLoweringInfo
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// instead for more accurate info.
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const char *Name = MO.getSymbolName();
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if (strcmp(Name, "memcpy") == 0 || strcmp(Name, "memmove") == 0 ||
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strcmp(Name, "memset") == 0)
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return false;
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return true;
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}
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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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