[llvm] r291882 - Track validity of pass results

Serge Pavlov via llvm-commits llvm-commits at lists.llvm.org
Thu Jan 12 22:09:54 PST 2017


Author: sepavloff
Date: Fri Jan 13 00:09:54 2017
New Revision: 291882

URL: http://llvm.org/viewvc/llvm-project?rev=291882&view=rev
Log:
Track validity of pass results

Running tests with expensive checks enabled exhibits some problems with
verification of pass results.

First, the pass verification may require results of analysis that are not
available. For instance, verification of loop info requires results of dominator
tree analysis. A pass may be marked as conserving loop info but does not need to
be dependent on DominatorTreePass. When a pass manager tries to verify that loop
info is valid, it needs dominator tree, but corresponding analysis may be
already destroyed as no user of it remained.

Another case is a pass that is skipped. For instance, entities with linkage
available_externally do not need code generation and such passes are skipped for
them. In this case result verification must also be skipped.

To solve these problems this change introduces a special flag to the Pass
structure to mark passes that have valid results. If this flag is reset,
verifications dependent on the pass result are skipped.

Differential Revision: https://reviews.llvm.org/D27190

Modified:
    llvm/trunk/include/llvm/Pass.h
    llvm/trunk/include/llvm/PassAnalysisSupport.h
    llvm/trunk/lib/Analysis/CallGraphSCCPass.cpp
    llvm/trunk/lib/Analysis/LoopInfo.cpp
    llvm/trunk/lib/Analysis/LoopPass.cpp
    llvm/trunk/lib/CodeGen/MachineDominators.cpp
    llvm/trunk/lib/CodeGen/MachineFunctionPass.cpp
    llvm/trunk/lib/IR/LegacyPassManager.cpp
    llvm/trunk/lib/IR/Pass.cpp
    llvm/trunk/test/CodeGen/Generic/externally_available.ll
    llvm/trunk/test/CodeGen/Mips/mul.ll

Modified: llvm/trunk/include/llvm/Pass.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Pass.h?rev=291882&r1=291881&r2=291882&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Pass.h (original)
+++ llvm/trunk/include/llvm/Pass.h Fri Jan 13 00:09:54 2017
@@ -29,6 +29,7 @@
 #ifndef LLVM_PASS_H
 #define LLVM_PASS_H
 
+#include <assert.h>
 #include <string>
 
 namespace llvm {
@@ -82,17 +83,40 @@ class Pass {
   AnalysisResolver *Resolver;  // Used to resolve analysis
   const void *PassID;
   PassKind Kind;
+  bool Executed;
+
   void operator=(const Pass&) = delete;
   Pass(const Pass &) = delete;
 
 public:
   explicit Pass(PassKind K, char &pid)
-    : Resolver(nullptr), PassID(&pid), Kind(K) { }
+    : Resolver(nullptr), PassID(&pid), Kind(K), Executed(false) { }
   virtual ~Pass();
 
-
   PassKind getPassKind() const { return Kind; }
 
+  /// Returns true if the pass has already executed.
+  ///
+  /// For an analysis pass it means the result is available. If the function
+  /// returns false, the pass was not run, was skipped or freed.
+  ///
+  bool isExecuted() const { return Executed; }
+
+  /// Marks the pass as executed or not.
+  ///
+  /// A pass should be marked as executed, if its 'runOn*' method successfully
+  /// finished. When the pass is not needed anymore, it is marked as
+  /// 'non-executed', it takes place in \c freePass. It also occurs when the
+  /// pass is skipped for some reason.
+  ///
+  /// The flag should be set prior to call to 'runOn*' method. If it decides
+  /// that the pass should be skipped, it will reset the flag.
+  ///
+  void setExecuted(bool x) {
+    assert(x || !getAsImmutablePass()); // Immutable pass cannot be invalidated.
+    Executed = x;
+  }
+
   /// getPassName - Return a nice clean name for a pass.  This usually
   /// implemented in terms of the name that is registered by one of the
   /// Registration templates, but can be overloaded directly.
@@ -279,8 +303,7 @@ public:
   ///
   bool runOnModule(Module &) override { return false; }
 
-  explicit ImmutablePass(char &pid)
-  : ModulePass(pid) {}
+  explicit ImmutablePass(char &pid) : ModulePass(pid) { setExecuted(true); }
 
   // Force out-of-line virtual method.
   ~ImmutablePass() override;
@@ -316,8 +339,9 @@ public:
 protected:
   /// Optional passes call this function to check whether the pass should be
   /// skipped. This is the case when Attribute::OptimizeNone is set or when
-  /// optimization bisect is over the limit.
-  bool skipFunction(const Function &F) const;
+  /// optimization bisect is over the limit. It also resets flag Executed on
+  /// the pass.
+  bool skipFunction(const Function &F);
 };
 
 

Modified: llvm/trunk/include/llvm/PassAnalysisSupport.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/PassAnalysisSupport.h?rev=291882&r1=291881&r2=291882&view=diff
==============================================================================
--- llvm/trunk/include/llvm/PassAnalysisSupport.h (original)
+++ llvm/trunk/include/llvm/PassAnalysisSupport.h Fri Jan 13 00:09:54 2017
@@ -206,6 +206,9 @@ AnalysisType *Pass::getAnalysisIfAvailab
   Pass *ResultPass = Resolver->getAnalysisIfAvailable(PI, true);
   if (!ResultPass) return nullptr;
 
+  if (!ResultPass->isExecuted())
+    return nullptr;
+
   // Because the AnalysisType may not be a subclass of pass (for
   // AnalysisGroups), we use getAdjustedAnalysisPointer here to potentially
   // adjust the return pointer (because the class may multiply inherit, once
@@ -234,6 +237,8 @@ AnalysisType &Pass::getAnalysisID(Analys
   assert (ResultPass && 
           "getAnalysis*() called on an analysis that was not "
           "'required' by pass!");
+  assert(ResultPass->isExecuted() &&
+         "getAnalysis*() called on an analysis that was freed");
 
   // Because the AnalysisType may not be a subclass of pass (for
   // AnalysisGroups), we use getAdjustedAnalysisPointer here to potentially

Modified: llvm/trunk/lib/Analysis/CallGraphSCCPass.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/CallGraphSCCPass.cpp?rev=291882&r1=291881&r2=291882&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/CallGraphSCCPass.cpp (original)
+++ llvm/trunk/lib/Analysis/CallGraphSCCPass.cpp Fri Jan 13 00:09:54 2017
@@ -414,6 +414,7 @@ bool CGPassManager::RunAllPassesOnSCC(Ca
     initializeAnalysisImpl(P);
     
     // Actually run this pass on the current SCC.
+    P->setExecuted(true);
     Changed |= RunPassOnSCC(P, CurSCC, CG,
                             CallGraphUpToDate, DevirtualizedCall);
     

Modified: llvm/trunk/lib/Analysis/LoopInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/LoopInfo.cpp?rev=291882&r1=291881&r2=291882&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/LoopInfo.cpp (original)
+++ llvm/trunk/lib/Analysis/LoopInfo.cpp Fri Jan 13 00:09:54 2017
@@ -722,8 +722,10 @@ void LoopInfoWrapperPass::verifyAnalysis
   // checking by default, LoopPass has been taught to call verifyLoop manually
   // during loop pass sequences.
   if (VerifyLoopInfo) {
-    auto &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();
-    LI.verify(DT);
+    if (auto *Analysis = getAnalysisIfAvailable<DominatorTreeWrapperPass>()) {
+      auto &DT = Analysis->getDomTree();
+      LI.verify(DT);
+    }
   }
 }
 

Modified: llvm/trunk/lib/Analysis/LoopPass.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/LoopPass.cpp?rev=291882&r1=291881&r2=291882&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/LoopPass.cpp (original)
+++ llvm/trunk/lib/Analysis/LoopPass.cpp Fri Jan 13 00:09:54 2017
@@ -198,6 +198,7 @@ bool LPPassManager::runOnFunction(Functi
         PassManagerPrettyStackEntry X(P, *CurrentLoop->getHeader());
         TimeRegion PassTimer(getPassTimer(P));
 
+        P->setExecuted(true);
         Changed |= P->runOnLoop(CurrentLoop, *this);
       }
       LoopWasDeleted = CurrentLoop->isInvalid();

Modified: llvm/trunk/lib/CodeGen/MachineDominators.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MachineDominators.cpp?rev=291882&r1=291881&r2=291882&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/MachineDominators.cpp (original)
+++ llvm/trunk/lib/CodeGen/MachineDominators.cpp Fri Jan 13 00:09:54 2017
@@ -69,7 +69,7 @@ void MachineDominatorTree::releaseMemory
 }
 
 void MachineDominatorTree::verifyAnalysis() const {
-  if (VerifyMachineDomInfo)
+  if (VerifyMachineDomInfo && isExecuted())
     verifyDomTree();
 }
 

Modified: llvm/trunk/lib/CodeGen/MachineFunctionPass.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MachineFunctionPass.cpp?rev=291882&r1=291881&r2=291882&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/MachineFunctionPass.cpp (original)
+++ llvm/trunk/lib/CodeGen/MachineFunctionPass.cpp Fri Jan 13 00:09:54 2017
@@ -38,8 +38,10 @@ Pass *MachineFunctionPass::createPrinter
 bool MachineFunctionPass::runOnFunction(Function &F) {
   // Do not codegen any 'available_externally' functions at all, they have
   // definitions outside the translation unit.
-  if (F.hasAvailableExternallyLinkage())
+  if (F.hasAvailableExternallyLinkage()) {
+    setExecuted(false);
     return false;
+  }
 
   MachineModuleInfo &MMI = getAnalysis<MachineModuleInfo>();
   MachineFunction &MF = MMI.getMachineFunction(F);

Modified: llvm/trunk/lib/IR/LegacyPassManager.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/LegacyPassManager.cpp?rev=291882&r1=291881&r2=291882&view=diff
==============================================================================
--- llvm/trunk/lib/IR/LegacyPassManager.cpp (original)
+++ llvm/trunk/lib/IR/LegacyPassManager.cpp Fri Jan 13 00:09:54 2017
@@ -955,6 +955,9 @@ void PMDataManager::freePass(Pass *P, St
         AvailableAnalysis.erase(Pos);
     }
   }
+
+  if (!P->getAsImmutablePass())
+    P->setExecuted(false);
 }
 
 /// Add pass P into the PassVector. Update
@@ -1293,6 +1296,7 @@ bool BBPassManager::runOnFunction(Functi
         PassManagerPrettyStackEntry X(BP, *I);
         TimeRegion PassTimer(getPassTimer(BP));
 
+        BP->setExecuted(true);
         LocalChanged |= BP->runOnBasicBlock(*I);
       }
 
@@ -1459,7 +1463,9 @@ bool FunctionPassManagerImpl::run(Functi
 
   initializeAllAnalysisInfo();
   for (unsigned Index = 0; Index < getNumContainedManagers(); ++Index) {
-    Changed |= getContainedManager(Index)->runOnFunction(F);
+    FPPassManager *P = getContainedManager(Index);
+    P->setExecuted(true);
+    Changed |= P->runOnFunction(F);
     F.getContext().yield();
   }
 
@@ -1510,6 +1516,7 @@ bool FPPassManager::runOnFunction(Functi
       PassManagerPrettyStackEntry X(FP, F);
       TimeRegion PassTimer(getPassTimer(FP));
 
+      FP->setExecuted(true);
       LocalChanged |= FP->runOnFunction(F);
     }
 
@@ -1530,8 +1537,10 @@ bool FPPassManager::runOnFunction(Functi
 bool FPPassManager::runOnModule(Module &M) {
   bool Changed = false;
 
-  for (Function &F : M)
+  for (Function &F : M) {
+    setExecuted(true);
     Changed |= runOnFunction(F);
+  }
 
   return Changed;
 }
@@ -1587,6 +1596,7 @@ MPPassManager::runOnModule(Module &M) {
       PassManagerPrettyStackEntry X(MP, M);
       TimeRegion PassTimer(getPassTimer(MP));
 
+      MP->setExecuted(true);
       LocalChanged |= MP->runOnModule(M);
     }
 
@@ -1690,7 +1700,9 @@ bool PassManagerImpl::run(Module &M) {
 
   initializeAllAnalysisInfo();
   for (unsigned Index = 0; Index < getNumContainedManagers(); ++Index) {
-    Changed |= getContainedManager(Index)->runOnModule(M);
+    MPPassManager *P = getContainedManager(Index);
+    P->setExecuted(true);
+    Changed |= P->runOnModule(M);
     M.getContext().yield();
   }
 

Modified: llvm/trunk/lib/IR/Pass.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/Pass.cpp?rev=291882&r1=291881&r2=291882&view=diff
==============================================================================
--- llvm/trunk/lib/IR/Pass.cpp (original)
+++ llvm/trunk/lib/IR/Pass.cpp Fri Jan 13 00:09:54 2017
@@ -146,13 +146,16 @@ PassManagerType FunctionPass::getPotenti
   return PMT_FunctionPassManager;
 }
 
-bool FunctionPass::skipFunction(const Function &F) const {
-  if (!F.getContext().getOptBisect().shouldRunPass(this, F))
+bool FunctionPass::skipFunction(const Function &F) {
+  if (!F.getContext().getOptBisect().shouldRunPass(this, F)) {
+    setExecuted(false);
     return true;
+  }
 
   if (F.hasFnAttribute(Attribute::OptimizeNone)) {
     DEBUG(dbgs() << "Skipping pass '" << getPassName() << "' on function "
                  << F.getName() << "\n");
+    setExecuted(false);
     return true;
   }
   return false;

Modified: llvm/trunk/test/CodeGen/Generic/externally_available.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/Generic/externally_available.ll?rev=291882&r1=291881&r2=291882&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/Generic/externally_available.ll (original)
+++ llvm/trunk/test/CodeGen/Generic/externally_available.ll Fri Jan 13 00:09:54 2017
@@ -1,4 +1,4 @@
-; RUN: llc < %s | not grep test_
+; RUN: llc -verify-machine-dom-info < %s | not grep test_
 
 ; test_function should not be emitted to the .s file.
 define available_externally i32 @test_function() {

Modified: llvm/trunk/test/CodeGen/Mips/mul.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/Mips/mul.ll?rev=291882&r1=291881&r2=291882&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/Mips/mul.ll (original)
+++ llvm/trunk/test/CodeGen/Mips/mul.ll Fri Jan 13 00:09:54 2017
@@ -1,4 +1,4 @@
-; RUN: llc  -march=mipsel -mattr=mips16 -relocation-model=pic -O3 < %s | FileCheck %s -check-prefix=16
+; RUN: llc  -march=mipsel -mattr=mips16 -relocation-model=pic -O3 -verify-loop-info < %s | FileCheck %s -check-prefix=16
 
 @iiii = global i32 5, align 4
 @jjjj = global i32 -6, align 4




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