[llvm] fcd6766 - [StackSafety] Add "Must Live" logic
Vitaly Buka via llvm-commits
llvm-commits at lists.llvm.org
Thu Jun 18 16:53:49 PDT 2020
Author: Vitaly Buka
Date: 2020-06-18T16:53:37-07:00
New Revision: fcd67665a8de61223313e1e1582faf17d9ee76b8
URL: https://github.com/llvm/llvm-project/commit/fcd67665a8de61223313e1e1582faf17d9ee76b8
DIFF: https://github.com/llvm/llvm-project/commit/fcd67665a8de61223313e1e1582faf17d9ee76b8.diff
LOG: [StackSafety] Add "Must Live" logic
Summary:
Extend StackLifetime with option to calculate liveliness
where alloca is only considered alive on basic block entry
if all non-dead predecessors had it alive at terminators.
Depends on D82043.
Reviewers: eugenis
Reviewed By: eugenis
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D82124
Added:
Modified:
llvm/include/llvm/Analysis/StackLifetime.h
llvm/lib/Analysis/StackLifetime.cpp
llvm/lib/CodeGen/SafeStack.cpp
llvm/lib/Passes/PassBuilder.cpp
llvm/lib/Passes/PassRegistry.def
llvm/test/Analysis/StackSafetyAnalysis/lifetime.ll
Removed:
################################################################################
diff --git a/llvm/include/llvm/Analysis/StackLifetime.h b/llvm/include/llvm/Analysis/StackLifetime.h
index 577d9ba177ea..40c826813696 100644
--- a/llvm/include/llvm/Analysis/StackLifetime.h
+++ b/llvm/include/llvm/Analysis/StackLifetime.h
@@ -13,6 +13,7 @@
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallVector.h"
+#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/PassManager.h"
#include "llvm/Support/raw_ostream.h"
@@ -78,8 +79,16 @@ class StackLifetime {
bool test(unsigned Idx) const { return Bits.test(Idx); }
};
+ // Controls what is "alive" if control flow may reach the instruction
+ // with a
diff erent liveness of the alloca.
+ enum class LivenessType {
+ May, // May be alive on some path.
+ Must, // Must be alive on every path.
+ };
+
private:
const Function &F;
+ LivenessType Type;
/// Maps active slots (per bit) for each basic block.
using LivenessMap = DenseMap<const BasicBlock *, BlockLifetimeInfo>;
@@ -124,7 +133,8 @@ class StackLifetime {
void calculateLiveIntervals();
public:
- StackLifetime(const Function &F, ArrayRef<const AllocaInst *> Allocas);
+ StackLifetime(const Function &F, ArrayRef<const AllocaInst *> Allocas,
+ LivenessType Type);
void run();
std::vector<const IntrinsicInst *> getMarkers() const;
@@ -168,10 +178,12 @@ inline raw_ostream &operator<<(raw_ostream &OS,
/// Printer pass for testing.
class StackLifetimePrinterPass
: public PassInfoMixin<StackLifetimePrinterPass> {
+ StackLifetime::LivenessType Type;
raw_ostream &OS;
public:
- explicit StackLifetimePrinterPass(raw_ostream &OS) : OS(OS) {}
+ StackLifetimePrinterPass(raw_ostream &OS, StackLifetime::LivenessType Type)
+ : Type(Type), OS(OS) {}
PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
};
diff --git a/llvm/lib/Analysis/StackLifetime.cpp b/llvm/lib/Analysis/StackLifetime.cpp
index efdfcf5c6c5c..9e4df6473ede 100644
--- a/llvm/lib/Analysis/StackLifetime.cpp
+++ b/llvm/lib/Analysis/StackLifetime.cpp
@@ -166,7 +166,17 @@ void StackLifetime::calculateLocalLiveness() {
// If a predecessor is unreachable, ignore it.
if (I == BlockLiveness.end())
continue;
- LocalLiveIn |= I->second.LiveOut;
+ switch (Type) {
+ case LivenessType::May:
+ LocalLiveIn |= I->second.LiveOut;
+ break;
+ case LivenessType::Must:
+ if (LocalLiveIn.empty())
+ LocalLiveIn = I->second.LiveOut;
+ else
+ LocalLiveIn &= I->second.LiveOut;
+ break;
+ }
}
// Compute LiveOut by subtracting out lifetimes that end in this
@@ -272,8 +282,9 @@ LLVM_DUMP_METHOD void StackLifetime::dumpLiveRanges() const {
#endif
StackLifetime::StackLifetime(const Function &F,
- ArrayRef<const AllocaInst *> Allocas)
- : F(F), Allocas(Allocas), NumAllocas(Allocas.size()) {
+ ArrayRef<const AllocaInst *> Allocas,
+ LivenessType Type)
+ : F(F), Type(Type), Allocas(Allocas), NumAllocas(Allocas.size()) {
LLVM_DEBUG(dumpAllocas());
for (unsigned I = 0; I < NumAllocas; ++I)
@@ -351,7 +362,7 @@ PreservedAnalyses StackLifetimePrinterPass::run(Function &F,
for (auto &I : instructions(F))
if (const AllocaInst *AI = dyn_cast<AllocaInst>(&I))
Allocas.push_back(AI);
- StackLifetime SL(F, Allocas);
+ StackLifetime SL(F, Allocas, Type);
SL.run();
SL.print(OS);
return PreservedAnalyses::all();
diff --git a/llvm/lib/CodeGen/SafeStack.cpp b/llvm/lib/CodeGen/SafeStack.cpp
index 1481894186e4..55478c232dd7 100644
--- a/llvm/lib/CodeGen/SafeStack.cpp
+++ b/llvm/lib/CodeGen/SafeStack.cpp
@@ -497,7 +497,7 @@ Value *SafeStack::moveStaticAllocasToUnsafeStack(
DIBuilder DIB(*F.getParent());
- StackLifetime SSC(F, StaticAllocas);
+ StackLifetime SSC(F, StaticAllocas, StackLifetime::LivenessType::May);
static const StackLifetime::LiveRange NoColoringRange(1, true);
if (ClColoring)
SSC.run();
diff --git a/llvm/lib/Passes/PassBuilder.cpp b/llvm/lib/Passes/PassBuilder.cpp
index 49866f35e7fd..d7f2a64e94d8 100644
--- a/llvm/lib/Passes/PassBuilder.cpp
+++ b/llvm/lib/Passes/PassBuilder.cpp
@@ -1851,6 +1851,26 @@ Expected<GVNOptions> parseGVNOptions(StringRef Params) {
return Result;
}
+Expected<StackLifetime::LivenessType>
+parseStackLifetimeOptions(StringRef Params) {
+ StackLifetime::LivenessType Result = StackLifetime::LivenessType::May;
+ while (!Params.empty()) {
+ StringRef ParamName;
+ std::tie(ParamName, Params) = Params.split(';');
+
+ if (ParamName == "may") {
+ Result = StackLifetime::LivenessType::May;
+ } else if (ParamName == "must") {
+ Result = StackLifetime::LivenessType::Must;
+ } else {
+ return make_error<StringError>(
+ formatv("invalid StackLifetime parameter '{0}' ", ParamName).str(),
+ inconvertibleErrorCode());
+ }
+ }
+ return Result;
+}
+
} // namespace
/// Tests whether a pass name starts with a valid prefix for a default pipeline
diff --git a/llvm/lib/Passes/PassRegistry.def b/llvm/lib/Passes/PassRegistry.def
index a38c651c673c..1edb0fe5c230 100644
--- a/llvm/lib/Passes/PassRegistry.def
+++ b/llvm/lib/Passes/PassRegistry.def
@@ -239,7 +239,6 @@ FUNCTION_PASS("print<phi-values>", PhiValuesPrinterPass(dbgs()))
FUNCTION_PASS("print<regions>", RegionInfoPrinterPass(dbgs()))
FUNCTION_PASS("print<scalar-evolution>", ScalarEvolutionPrinterPass(dbgs()))
FUNCTION_PASS("print<stack-safety-local>", StackSafetyPrinterPass(dbgs()))
-FUNCTION_PASS("print<stack-lifetime>", StackLifetimePrinterPass(dbgs()))
FUNCTION_PASS("reassociate", ReassociatePass())
FUNCTION_PASS("scalarizer", ScalarizerPass())
FUNCTION_PASS("sccp", SCCPPass())
@@ -302,6 +301,11 @@ FUNCTION_PASS_WITH_PARAMS("gvn",
return GVN(Opts);
},
parseGVNOptions)
+FUNCTION_PASS_WITH_PARAMS("print<stack-lifetime>",
+ [](StackLifetime::LivenessType Type) {
+ return StackLifetimePrinterPass(dbgs(), Type);
+ },
+ parseStackLifetimeOptions)
#undef FUNCTION_PASS_WITH_PARAMS
#ifndef LOOP_ANALYSIS
diff --git a/llvm/test/Analysis/StackSafetyAnalysis/lifetime.ll b/llvm/test/Analysis/StackSafetyAnalysis/lifetime.ll
index 61d0dc2286f6..d2ac1abdce6f 100644
--- a/llvm/test/Analysis/StackSafetyAnalysis/lifetime.ll
+++ b/llvm/test/Analysis/StackSafetyAnalysis/lifetime.ll
@@ -1,4 +1,5 @@
-; RUN: opt -passes='print<stack-lifetime>' -disable-output %s 2>&1 | FileCheck %s
+; RUN: opt -passes='print<stack-lifetime><may>' -disable-output %s 2>&1 | FileCheck %s --check-prefixes=CHECK,MAY
+; RUN: opt -passes='print<stack-lifetime><must>' -disable-output %s 2>&1 | FileCheck %s --check-prefixes=CHECK,MUST
define void @f() {
; CHECK-LABEL: define void @f()
@@ -710,7 +711,8 @@ entry:
l2: ; preds = %l2, %entry
; CHECK: l2:
-; CHECK-NEXT: Alive: <x>
+; MAY-NEXT: Alive: <x>
+; MUST-NEXT: Alive: <>
call void @capture8(i8* %x)
call void @llvm.lifetime.end.p0i8(i64 4, i8* %x)
; CHECK: call void @llvm.lifetime.end.p0i8(i64 4, i8* %x)
@@ -758,6 +760,55 @@ l2: ; preds = %l2, %entry
; CHECK-NEXT: Alive: <x>
}
+define void @if_must(i1 %a) {
+; CHECK-LABEL: define void @if_must
+entry:
+; CHECK: entry:
+; CHECK-NEXT: Alive: <>
+ %x = alloca i8, align 4
+ %y = alloca i8, align 4
+
+ br i1 %a, label %if.then, label %if.else
+; CHECK: br i1 %a
+; CHECK-NEXT: Alive: <>
+
+if.then:
+; CHECK: if.then:
+; CHECK-NEXT: Alive: <>
+ call void @llvm.lifetime.start.p0i8(i64 4, i8* %y)
+; CHECK: call void @llvm.lifetime.start.p0i8(i64 4, i8* %y)
+; CHECK-NEXT: Alive: <y>
+
+ br label %if.end
+; CHECK: br label %if.end
+; CHECK-NEXT: Alive: <y>
+
+if.else:
+; CHECK: if.else:
+; CHECK-NEXT: Alive: <>
+ call void @llvm.lifetime.start.p0i8(i64 4, i8* %y)
+; CHECK: call void @llvm.lifetime.start.p0i8(i64 4, i8* %y)
+; CHECK-NEXT: Alive: <y>
+
+ call void @llvm.lifetime.start.p0i8(i64 4, i8* %x)
+; CHECK: call void @llvm.lifetime.start.p0i8(i64 4, i8* %x)
+; CHECK-NEXT: Alive: <x y>
+
+ br label %if.end
+; CHECK: br label %if.end
+; CHECK-NEXT: Alive: <x y>
+
+if.end:
+; CHECK: if.end:
+; MAY-NEXT: Alive: <x y>
+; MUST-NEXT: Alive: <y>
+
+ret void
+; CHECK: ret void
+; MAY-NEXT: Alive: <x y>
+; MUST-NEXT: Alive: <y>
+}
+
declare void @llvm.lifetime.start.p0i8(i64, i8* nocapture)
declare void @llvm.lifetime.end.p0i8(i64, i8* nocapture)
declare void @capture8(i8*)
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