llvm/llvm/lib/Target/WebAssembly/WebAssemblyDebugFixup.cpp

//===-- WebAssemblyDebugFixup.cpp - Debug Fixup ------------------===//
//
// 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
/// Several prior passes may "stackify" registers, here we ensure any references
/// in such registers in debug_value instructions become stack relative also.
/// This is done in a separate pass such that not all previous passes need to
/// track stack depth when values get stackified.
///
//===----------------------------------------------------------------------===//

#include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
#include "WebAssembly.h"
#include "WebAssemblyMachineFunctionInfo.h"
#include "WebAssemblySubtarget.h"
#include "WebAssemblyUtilities.h"
#include "llvm/ADT/SCCIterator.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineLoopInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
usingnamespacellvm;

#define DEBUG_TYPE …

namespace {
class WebAssemblyDebugFixup final : public MachineFunctionPass { … };
} // end anonymous namespace

char WebAssemblyDebugFixup::ID = …;
INITIALIZE_PASS(…)

FunctionPass *llvm::createWebAssemblyDebugFixup() { … }

// At this very end of the compilation pipeline, if any DBG_VALUEs with
// registers remain, it means they are dangling info which we failed to update
// when their corresponding def instruction was transformed/moved/splitted etc.
// Because Wasm cannot access values in LLVM virtual registers in the debugger,
// these dangling DBG_VALUEs in effect kill the effect of any previous DBG_VALUE
// associated with the variable, which will appear as "optimized out".
static void setDanglingDebugValuesUndef(MachineBasicBlock &MBB,
                                        const TargetInstrInfo *TII) { … }

bool WebAssemblyDebugFixup::runOnMachineFunction(MachineFunction &MF) { … }