1562b70eaf
This relands commit #115111.
Use traditional way to update post dominator tree, i.e. break critical
edge splitting into insert, insert, delete sequence.
When splitting critical edges, the post dominator tree may change its
root node, and `setNewRoot` only works in normal dominator tree...
See
6c7e5827ed/llvm/include/llvm/Support/GenericDomTree.h (L684-L687)
132 lines
4.6 KiB
C++
132 lines
4.6 KiB
C++
//===- LiveDebugValues.cpp - Tracking Debug Value MIs ---------------------===//
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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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#include "LiveDebugValues.h"
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#include "llvm/CodeGen/MachineDominators.h"
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#include "llvm/CodeGen/MachineFunction.h"
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#include "llvm/CodeGen/MachineFunctionPass.h"
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#include "llvm/CodeGen/Passes.h"
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#include "llvm/CodeGen/TargetPassConfig.h"
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#include "llvm/InitializePasses.h"
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#include "llvm/Pass.h"
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#include "llvm/PassRegistry.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Target/TargetMachine.h"
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#include "llvm/TargetParser/Triple.h"
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/// \file LiveDebugValues.cpp
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///
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/// The LiveDebugValues pass extends the range of variable locations
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/// (specified by DBG_VALUE instructions) from single blocks to successors
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/// and any other code locations where the variable location is valid.
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/// There are currently two implementations: the "VarLoc" implementation
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/// explicitly tracks the location of a variable, while the "InstrRef"
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/// implementation tracks the values defined by instructions through locations.
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///
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/// This file implements neither; it merely registers the pass, allows the
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/// user to pick which implementation will be used to propagate variable
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/// locations.
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#define DEBUG_TYPE "livedebugvalues"
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using namespace llvm;
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static cl::opt<bool>
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ForceInstrRefLDV("force-instr-ref-livedebugvalues", cl::Hidden,
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cl::desc("Use instruction-ref based LiveDebugValues with "
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"normal DBG_VALUE inputs"),
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cl::init(false));
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static cl::opt<cl::boolOrDefault> ValueTrackingVariableLocations(
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"experimental-debug-variable-locations",
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cl::desc("Use experimental new value-tracking variable locations"));
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// Options to prevent pathological compile-time behavior. If InputBBLimit and
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// InputDbgValueLimit are both exceeded, range extension is disabled.
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static cl::opt<unsigned> InputBBLimit(
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"livedebugvalues-input-bb-limit",
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cl::desc("Maximum input basic blocks before DBG_VALUE limit applies"),
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cl::init(10000), cl::Hidden);
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static cl::opt<unsigned> InputDbgValueLimit(
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"livedebugvalues-input-dbg-value-limit",
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cl::desc(
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"Maximum input DBG_VALUE insts supported by debug range extension"),
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cl::init(50000), cl::Hidden);
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namespace {
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/// Generic LiveDebugValues pass. Calls through to VarLocBasedLDV or
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/// InstrRefBasedLDV to perform location propagation, via the LDVImpl
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/// base class.
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class LiveDebugValues : public MachineFunctionPass {
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public:
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static char ID;
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LiveDebugValues();
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~LiveDebugValues() = default;
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/// Calculate the liveness information for the given machine function.
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bool runOnMachineFunction(MachineFunction &MF) override;
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void getAnalysisUsage(AnalysisUsage &AU) const override {
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AU.setPreservesCFG();
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MachineFunctionPass::getAnalysisUsage(AU);
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}
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private:
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std::unique_ptr<LDVImpl> InstrRefImpl;
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std::unique_ptr<LDVImpl> VarLocImpl;
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TargetPassConfig *TPC = nullptr;
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MachineDominatorTree MDT;
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};
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} // namespace
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char LiveDebugValues::ID = 0;
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char &llvm::LiveDebugValuesID = LiveDebugValues::ID;
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INITIALIZE_PASS(LiveDebugValues, DEBUG_TYPE, "Live DEBUG_VALUE analysis", false,
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false)
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/// Default construct and initialize the pass.
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LiveDebugValues::LiveDebugValues() : MachineFunctionPass(ID) {
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initializeLiveDebugValuesPass(*PassRegistry::getPassRegistry());
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InstrRefImpl =
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std::unique_ptr<LDVImpl>(llvm::makeInstrRefBasedLiveDebugValues());
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VarLocImpl = std::unique_ptr<LDVImpl>(llvm::makeVarLocBasedLiveDebugValues());
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}
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bool LiveDebugValues::runOnMachineFunction(MachineFunction &MF) {
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bool InstrRefBased = MF.useDebugInstrRef();
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// Allow the user to force selection of InstrRef LDV.
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InstrRefBased |= ForceInstrRefLDV;
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TPC = getAnalysisIfAvailable<TargetPassConfig>();
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LDVImpl *TheImpl = &*VarLocImpl;
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MachineDominatorTree *DomTree = nullptr;
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if (InstrRefBased) {
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DomTree = &MDT;
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MDT.recalculate(MF);
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TheImpl = &*InstrRefImpl;
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}
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return TheImpl->ExtendRanges(MF, DomTree, TPC, InputBBLimit,
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InputDbgValueLimit);
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}
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bool llvm::debuginfoShouldUseDebugInstrRef(const Triple &T) {
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// Enable by default on x86_64, disable if explicitly turned off on cmdline.
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if (T.getArch() == llvm::Triple::x86_64 &&
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ValueTrackingVariableLocations != cl::boolOrDefault::BOU_FALSE)
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return true;
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// Enable if explicitly requested on command line.
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return ValueTrackingVariableLocations == cl::boolOrDefault::BOU_TRUE;
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}
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