[LiveDebugVariables] Add basic verification#79846
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In debug builds, mark slot indexes for deleted instructions as poisoned and add an isPoisoned method to allow writing assertions elsewhere in the compiler. This restores some of the functionality that was removed by 4cf8da9.
Add a basic implementation of verifyAnalysis that just checks that the analysis does not refer to any SlotIndexes for instructions that have been deleted. This was useful for diagnosing some SlotIndexes-related problems caused by llvm#67038.
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@llvm/pr-subscribers-debuginfo @llvm/pr-subscribers-llvm-regalloc Author: Jay Foad (jayfoad) ChangesAdd a basic implementation of verifyAnalysis that just checks that the Full diff: https://github.com/llvm/llvm-project/pull/79846.diff 4 Files Affected:
diff --git a/llvm/include/llvm/CodeGen/SlotIndexes.h b/llvm/include/llvm/CodeGen/SlotIndexes.h
index 72f4a6876b6cb14..2b437a0649aac22 100644
--- a/llvm/include/llvm/CodeGen/SlotIndexes.h
+++ b/llvm/include/llvm/CodeGen/SlotIndexes.h
@@ -43,21 +43,40 @@ class raw_ostream;
/// SlotIndex & SlotIndexes classes for the public interface to this
/// information.
class IndexListEntry : public ilist_node<IndexListEntry> {
- MachineInstr *mi;
+#if NDEBUG
+ // Disable poison checks such that setPoison will do nothing and isPoisoned
+ // will return false.
+ static constexpr unsigned PoisonBits = 0;
+ static constexpr unsigned PoisonVal = 0;
+#else
+ static constexpr unsigned PoisonBits = 1;
+ static constexpr unsigned PoisonVal = 1;
+#endif
+
+ PointerIntPair<MachineInstr *, PoisonBits, unsigned> mi;
unsigned index;
public:
- IndexListEntry(MachineInstr *mi, unsigned index) : mi(mi), index(index) {}
+ IndexListEntry(MachineInstr *mi, unsigned index) : mi(mi, 0), index(index) {
+ }
- MachineInstr* getInstr() const { return mi; }
+ MachineInstr* getInstr() const { return mi.getPointer(); }
void setInstr(MachineInstr *mi) {
- this->mi = mi;
+ this->mi.setPointer(mi);
}
unsigned getIndex() const { return index; }
void setIndex(unsigned index) {
this->index = index;
}
+
+ void setPoison() {
+ mi.setInt(PoisonVal);
+ }
+
+ bool isPoisoned() const {
+ return mi.getInt();
+ }
};
template <>
@@ -285,6 +304,10 @@ class raw_ostream;
SlotIndex getPrevIndex() const {
return SlotIndex(&*--listEntry()->getIterator(), getSlot());
}
+
+ bool isPoisoned() const {
+ return listEntry()->isPoisoned();
+ }
};
inline raw_ostream& operator<<(raw_ostream &os, SlotIndex li) {
diff --git a/llvm/lib/CodeGen/LiveDebugVariables.cpp b/llvm/lib/CodeGen/LiveDebugVariables.cpp
index 7cb90af5ff173ed..93b9566b21370ad 100644
--- a/llvm/lib/CodeGen/LiveDebugVariables.cpp
+++ b/llvm/lib/CodeGen/LiveDebugVariables.cpp
@@ -492,6 +492,13 @@ class UserValue {
/// Return DebugLoc of this UserValue.
const DebugLoc &getDebugLoc() { return dl; }
+ void verify() const {
+ for (auto I = locInts.begin(), E = locInts.end(); I != E; ++I) {
+ assert(!I.start().isPoisoned());
+ assert(!I.stop().isPoisoned());
+ }
+ }
+
void print(raw_ostream &, const TargetRegisterInfo *);
};
@@ -655,6 +662,11 @@ class LDVImpl {
ModifiedMF = false;
}
+ void verify() const {
+ for (auto [DV, UV] : userVarMap)
+ UV->verify();
+ }
+
/// Map virtual register to an equivalence class.
void mapVirtReg(Register VirtReg, UserValue *EC);
@@ -1320,6 +1332,11 @@ void LiveDebugVariables::releaseMemory() {
static_cast<LDVImpl*>(pImpl)->clear();
}
+void LiveDebugVariables::verifyAnalysis() const {
+ if (pImpl)
+ static_cast<LDVImpl *>(pImpl)->verify();
+}
+
LiveDebugVariables::~LiveDebugVariables() {
if (pImpl)
delete static_cast<LDVImpl*>(pImpl);
diff --git a/llvm/lib/CodeGen/LiveDebugVariables.h b/llvm/lib/CodeGen/LiveDebugVariables.h
index 9998ce9e8dad861..c99f11c8565a819 100644
--- a/llvm/lib/CodeGen/LiveDebugVariables.h
+++ b/llvm/lib/CodeGen/LiveDebugVariables.h
@@ -56,6 +56,7 @@ class LLVM_LIBRARY_VISIBILITY LiveDebugVariables : public MachineFunctionPass {
bool runOnMachineFunction(MachineFunction &) override;
void releaseMemory() override;
void getAnalysisUsage(AnalysisUsage &) const override;
+ void verifyAnalysis() const override;
MachineFunctionProperties getSetProperties() const override {
return MachineFunctionProperties().set(
diff --git a/llvm/lib/CodeGen/SlotIndexes.cpp b/llvm/lib/CodeGen/SlotIndexes.cpp
index 8b80c6ccb438936..762aab2ec2557e3 100644
--- a/llvm/lib/CodeGen/SlotIndexes.cpp
+++ b/llvm/lib/CodeGen/SlotIndexes.cpp
@@ -126,6 +126,7 @@ void SlotIndexes::removeMachineInstrFromMaps(MachineInstr &MI,
mi2iMap.erase(mi2iItr);
// FIXME: Eventually we want to actually delete these indexes.
MIEntry.setInstr(nullptr);
+ MIEntry.setPoison();
}
void SlotIndexes::removeSingleMachineInstrFromMaps(MachineInstr &MI) {
@@ -152,6 +153,7 @@ void SlotIndexes::removeSingleMachineInstrFromMaps(MachineInstr &MI) {
} else {
// FIXME: Eventually we want to actually delete these indexes.
MIEntry.setInstr(nullptr);
+ MIEntry.setPoison();
}
}
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✅ With the latest revision this PR passed the C/C++ code formatter. |
| const DebugLoc &getDebugLoc() { return dl; } | ||
|
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||
| void verify() const { | ||
| for (auto I = locInts.begin(), E = locInts.end(); I != E; ++I) { |
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Suggested change
| for (auto I = locInts.begin(), E = locInts.end(); I != E; ++I) { | |
| for (auto I : locInts) { |
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I don't think this works because I need to call start and stop which are methods on the iterator itself (an instance of IntervalMap::const_iterator).
SLTozer
approved these changes
Jan 30, 2024
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Adding the verification SGTM - LiveDebugVariables can be a moderately hot pass (though LiveDebugValues is the real killer) and PointerIntPair can cause a bit of a slowdown compared to just pointer operations, but I expect this won't have a noticeable impact.
Contributor
Author
I should have mentioned that I cannot commit this patch as-is because it causes lit test failures. I think these are all pre-existing problems with LiveDebugVariables that would need to be fixed. There was some prior discussion about this in the previous iteration of this review, #68703. I'd appreciate any help with understanding or fixing the failures! |
You can test this locally with the following command:Build idt from compnerd/ids, then for each changed header:
idt -p build/ --main-file <matching-source.cpp> \
--apply-fixits --inplace <header>View the diff from ids-check here.diff --git a/llvm/include/llvm/CodeGen/LiveDebugVariables.h b/llvm/include/llvm/CodeGen/LiveDebugVariables.h
index a88579f14..100ebb4fd 100644
--- a/llvm/include/llvm/CodeGen/LiveDebugVariables.h
+++ b/llvm/include/llvm/CodeGen/LiveDebugVariables.h
@@ -61,7 +61,7 @@ public:
LLVM_ABI void releaseMemory();
- void verifyAnalysis() const;
+ LLVM_ABI void verifyAnalysis() const;
LLVM_ABI bool invalidate(MachineFunction &MF, const PreservedAnalyses &PA,
MachineFunctionAnalysisManager::Invalidator &Inv);
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🐧 Linux x64 Test Results
Failed Tests(click on a test name to see its output) LLVMLLVM.CodeGen/Thumb2/pr52817.llLLVM.CodeGen/X86/debug-spilled-snippet.llLLVM.CodeGen/X86/debug-spilled-snippet.mirLLVM.DebugInfo/ARM/PR26163.llLLVM.DebugInfo/COFF/fpo-csrs.llLLVM.DebugInfo/X86/pr34545.llLLVM.DebugInfo/X86/spill-indirect-nrvo.llLLVM.tools/llvm-dwarfdump/X86/LTO_CCU_zero_loc_cov.llIf these failures are unrelated to your changes (for example tests are broken or flaky at HEAD), please open an issue at https://github.com/llvm/llvm-project/issues and add the |
🪟 Windows x64 Test Results
Failed Tests(click on a test name to see its output) LLVMLLVM.CodeGen/Thumb2/pr52817.llLLVM.CodeGen/X86/debug-spilled-snippet.llLLVM.CodeGen/X86/debug-spilled-snippet.mirLLVM.DebugInfo/ARM/PR26163.llLLVM.DebugInfo/COFF/fpo-csrs.llLLVM.DebugInfo/X86/pr34545.llLLVM.DebugInfo/X86/spill-indirect-nrvo.llLLVM.tools/llvm-dwarfdump/X86/LTO_CCU_zero_loc_cov.llIf these failures are unrelated to your changes (for example tests are broken or flaky at HEAD), please open an issue at https://github.com/llvm/llvm-project/issues and add the |
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Add a basic implementation of verifyAnalysis that just checks that the
analysis does not refer to any SlotIndexes for instructions that have
been deleted. This was useful for diagnosing some SlotIndexes-related
problems caused by #67038.