r218296 - Reverting r214064 and r215650 while investigating a pesky performance regression
Artyom Skrobov
Artyom.Skrobov at arm.com
Tue Sep 23 01:34:42 PDT 2014
Author: askrobov
Date: Tue Sep 23 03:34:41 2014
New Revision: 218296
URL: http://llvm.org/viewvc/llvm-project?rev=218296&view=rev
Log:
Reverting r214064 and r215650 while investigating a pesky performance regression
Removed:
cfe/trunk/include/clang/Analysis/Analyses/DataflowWorklist.h
cfe/trunk/lib/Analysis/DataflowWorklist.cpp
Modified:
cfe/trunk/include/clang/Analysis/Analyses/PostOrderCFGView.h
cfe/trunk/include/clang/Analysis/Analyses/ThreadSafetyCommon.h
cfe/trunk/lib/Analysis/CMakeLists.txt
cfe/trunk/lib/Analysis/Consumed.cpp
cfe/trunk/lib/Analysis/LiveVariables.cpp
cfe/trunk/lib/Analysis/PostOrderCFGView.cpp
cfe/trunk/lib/Analysis/UninitializedValues.cpp
Removed: cfe/trunk/include/clang/Analysis/Analyses/DataflowWorklist.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Analysis/Analyses/DataflowWorklist.h?rev=218295&view=auto
==============================================================================
--- cfe/trunk/include/clang/Analysis/Analyses/DataflowWorklist.h (original)
+++ cfe/trunk/include/clang/Analysis/Analyses/DataflowWorklist.h (removed)
@@ -1,61 +0,0 @@
-//===- DataflowWorklist.h - worklist for dataflow analysis --------*- C++ --*-//
-//
-// The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// DataflowWorklist keeps track of blocks for dataflow analysis. It maintains a
-// vector of blocks for priority processing, and falls back upon a reverse
-// post-order iterator. It supports both forward (used in UninitializedValues)
-// and backward (used in LiveVariables) analyses.
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef LLVM_CLANG_ANALYSIS_ANALYSES_DATAFLOWWORKLIST_H
-#define LLVM_CLANG_ANALYSIS_ANALYSES_DATAFLOWWORKLIST_H
-
-#include "clang/Analysis/Analyses/PostOrderCFGView.h"
-
-namespace clang {
-
-class DataflowWorklist {
- PostOrderCFGView::iterator PO_I, PO_E;
- SmallVector<const CFGBlock *, 20> worklist;
- llvm::BitVector enqueuedBlocks;
-
-protected:
- DataflowWorklist(const CFG &cfg, PostOrderCFGView &view)
- : PO_I(view.begin()), PO_E(view.end()),
- enqueuedBlocks(cfg.getNumBlockIDs(), true) {
- // For forward analysis, treat the first block as already analyzed.
- if ((PO_I != PO_E) && (*PO_I == &cfg.getEntry())) {
- enqueuedBlocks[(*PO_I)->getBlockID()] = false;
- ++PO_I;
- }
- }
-
-public:
- void enqueueBlock(const CFGBlock *block);
- void enqueuePredecessors(const CFGBlock *block);
- void enqueueSuccessors(const CFGBlock *block);
- const CFGBlock *dequeue();
-};
-
-class BackwardDataflowWorklist : public DataflowWorklist {
-public:
- BackwardDataflowWorklist(const CFG &cfg, AnalysisDeclContext &Ctx)
- : DataflowWorklist(cfg, *Ctx.getAnalysis<PostOrderCFGView>()) {}
-};
-
-class ForwardDataflowWorklist : public DataflowWorklist {
-public:
- ForwardDataflowWorklist(const CFG &cfg, AnalysisDeclContext &Ctx)
- : DataflowWorklist(cfg, *Ctx.getAnalysis<ReversePostOrderCFGView>()) {}
-};
-
-} // end clang namespace
-
-#endif
Modified: cfe/trunk/include/clang/Analysis/Analyses/PostOrderCFGView.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Analysis/Analyses/PostOrderCFGView.h?rev=218296&r1=218295&r2=218296&view=diff
==============================================================================
--- cfe/trunk/include/clang/Analysis/Analyses/PostOrderCFGView.h (original)
+++ cfe/trunk/include/clang/Analysis/Analyses/PostOrderCFGView.h Tue Sep 23 03:34:41 2014
@@ -7,7 +7,7 @@
//
//===----------------------------------------------------------------------===//
//
-// This file implements post order views of the blocks in a CFG.
+// This file implements post order view of the blocks in a CFG.
//
//===----------------------------------------------------------------------===//
@@ -68,7 +68,8 @@ public:
}
};
-protected:
+private:
+ typedef llvm::po_iterator<const CFG*, CFGBlockSet, true> po_iterator;
std::vector<const CFGBlock*> Blocks;
typedef llvm::DenseMap<const CFGBlock *, unsigned> BlockOrderTy;
@@ -106,15 +107,6 @@ public:
static const void *getTag();
static PostOrderCFGView *create(AnalysisDeclContext &analysisContext);
-
-protected:
- PostOrderCFGView() {}
-};
-
-class ReversePostOrderCFGView : public PostOrderCFGView {
-public:
- ReversePostOrderCFGView(const CFG *cfg);
- static ReversePostOrderCFGView *create(AnalysisDeclContext &analysisContext);
};
} // end clang namespace
Modified: cfe/trunk/include/clang/Analysis/Analyses/ThreadSafetyCommon.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Analysis/Analyses/ThreadSafetyCommon.h?rev=218296&r1=218295&r2=218296&view=diff
==============================================================================
--- cfe/trunk/include/clang/Analysis/Analyses/ThreadSafetyCommon.h (original)
+++ cfe/trunk/include/clang/Analysis/Analyses/ThreadSafetyCommon.h Tue Sep 23 03:34:41 2014
@@ -142,7 +142,7 @@ public:
if (!dyn_cast_or_null<NamedDecl>(AC.getDecl()))
return false;
- SortedGraph = AC.getAnalysis<ReversePostOrderCFGView>();
+ SortedGraph = AC.getAnalysis<PostOrderCFGView>();
if (!SortedGraph)
return false;
Modified: cfe/trunk/lib/Analysis/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Analysis/CMakeLists.txt?rev=218296&r1=218295&r2=218296&view=diff
==============================================================================
--- cfe/trunk/lib/Analysis/CMakeLists.txt (original)
+++ cfe/trunk/lib/Analysis/CMakeLists.txt Tue Sep 23 03:34:41 2014
@@ -13,7 +13,6 @@ add_clang_library(clangAnalysis
Consumed.cpp
CodeInjector.cpp
Dominators.cpp
- DataflowWorklist.cpp
FormatString.cpp
LiveVariables.cpp
ObjCNoReturn.cpp
Modified: cfe/trunk/lib/Analysis/Consumed.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Analysis/Consumed.cpp?rev=218296&r1=218295&r2=218296&view=diff
==============================================================================
--- cfe/trunk/lib/Analysis/Consumed.cpp (original)
+++ cfe/trunk/lib/Analysis/Consumed.cpp Tue Sep 23 03:34:41 2014
@@ -1360,7 +1360,7 @@ void ConsumedAnalyzer::run(AnalysisDeclC
determineExpectedReturnState(AC, D);
- PostOrderCFGView *SortedGraph = AC.getAnalysis<ReversePostOrderCFGView>();
+ PostOrderCFGView *SortedGraph = AC.getAnalysis<PostOrderCFGView>();
// AC.getCFG()->viewCFG(LangOptions());
BlockInfo = ConsumedBlockInfo(CFGraph->getNumBlockIDs(), SortedGraph);
Removed: cfe/trunk/lib/Analysis/DataflowWorklist.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Analysis/DataflowWorklist.cpp?rev=218295&view=auto
==============================================================================
--- cfe/trunk/lib/Analysis/DataflowWorklist.cpp (original)
+++ cfe/trunk/lib/Analysis/DataflowWorklist.cpp (removed)
@@ -1,79 +0,0 @@
-//===- DataflowWorklist.cpp - worklist for dataflow analysis ------*- C++ --*-//
-//
-// The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// DataflowWorklist is used in LiveVariables and UninitializedValues analyses
-//
-//===----------------------------------------------------------------------===//
-
-#include "clang/Analysis/Analyses/DataflowWorklist.h"
-
-using namespace clang;
-
-// Marking a block as enqueued means that it cannot be re-added to the worklist,
-// but it doesn't control when the algorithm terminates.
-// Initially, enqueuedBlocks is set to true for all blocks;
-// that's not because everything is added initially to the worklist,
-// but instead, to cause the analysis to follow the initial graph traversal
-// until we enqueue something on the worklist.
-void DataflowWorklist::enqueueBlock(const clang::CFGBlock *block) {
- if (block && !enqueuedBlocks[block->getBlockID()]) {
- enqueuedBlocks[block->getBlockID()] = true;
- worklist.push_back(block);
- }
-}
-
-// The analysis alternates between essentially two worklists.
-// A prioritization worklist (SmallVector<const CFGBlock *> worklist)
-// is consulted first, and if it's empty, we consult
-// PostOrderCFGView::iterator PO_I, which implements either post-order traversal
-// for backward analysis, or reverse post-order traversal for forward analysis.
-// The prioritization worklist is used to prioritize analyzing from
-// the beginning, or to prioritize updates fed by back edges.
-// Typically, what gets enqueued on the worklist are back edges, which
-// we want to prioritize analyzing first, because that causes dataflow facts
-// to flow up the graph, which we then want to propagate forward.
-// In practice this can cause the analysis to converge much faster.
-void DataflowWorklist::enqueueSuccessors(const clang::CFGBlock *block) {
- for (CFGBlock::const_succ_iterator I = block->succ_begin(),
- E = block->succ_end(); I != E; ++I) {
- enqueueBlock(*I);
- }
-}
-
-void DataflowWorklist::enqueuePredecessors(const clang::CFGBlock *block) {
- for (CFGBlock::const_pred_iterator I = block->pred_begin(),
- E = block->pred_end(); I != E; ++I) {
- enqueueBlock(*I);
- }
-}
-
-const CFGBlock *DataflowWorklist::dequeue() {
- const CFGBlock *B = nullptr;
-
- // First dequeue from the worklist. This can represent
- // updates along backedges that we want propagated as quickly as possible.
- if (!worklist.empty())
- B = worklist.pop_back_val();
-
- // Next dequeue from the initial graph traversal (either post order or
- // reverse post order). This is the theoretical ideal in the presence
- // of no back edges.
- else if (PO_I != PO_E) {
- B = *PO_I;
- ++PO_I;
- }
- else {
- return nullptr;
- }
-
- assert(enqueuedBlocks[B->getBlockID()] == true);
- enqueuedBlocks[B->getBlockID()] = false;
- return B;
-}
-
Modified: cfe/trunk/lib/Analysis/LiveVariables.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Analysis/LiveVariables.cpp?rev=218296&r1=218295&r2=218296&view=diff
==============================================================================
--- cfe/trunk/lib/Analysis/LiveVariables.cpp (original)
+++ cfe/trunk/lib/Analysis/LiveVariables.cpp Tue Sep 23 03:34:41 2014
@@ -14,10 +14,11 @@
#include "clang/Analysis/Analyses/LiveVariables.h"
#include "clang/AST/Stmt.h"
#include "clang/AST/StmtVisitor.h"
-#include "clang/Analysis/Analyses/DataflowWorklist.h"
+#include "clang/Analysis/Analyses/PostOrderCFGView.h"
#include "clang/Analysis/AnalysisContext.h"
#include "clang/Analysis/CFG.h"
#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <vector>
@@ -25,6 +26,59 @@
using namespace clang;
namespace {
+
+class DataflowWorklist {
+ SmallVector<const CFGBlock *, 20> worklist;
+ llvm::BitVector enqueuedBlocks;
+ PostOrderCFGView *POV;
+public:
+ DataflowWorklist(const CFG &cfg, AnalysisDeclContext &Ctx)
+ : enqueuedBlocks(cfg.getNumBlockIDs()),
+ POV(Ctx.getAnalysis<PostOrderCFGView>()) {}
+
+ void enqueueBlock(const CFGBlock *block);
+ void enqueuePredecessors(const CFGBlock *block);
+
+ const CFGBlock *dequeue();
+
+ void sortWorklist();
+};
+
+}
+
+void DataflowWorklist::enqueueBlock(const clang::CFGBlock *block) {
+ if (block && !enqueuedBlocks[block->getBlockID()]) {
+ enqueuedBlocks[block->getBlockID()] = true;
+ worklist.push_back(block);
+ }
+}
+
+void DataflowWorklist::enqueuePredecessors(const clang::CFGBlock *block) {
+ const unsigned OldWorklistSize = worklist.size();
+ for (CFGBlock::const_pred_iterator I = block->pred_begin(),
+ E = block->pred_end(); I != E; ++I) {
+ enqueueBlock(*I);
+ }
+
+ if (OldWorklistSize == 0 || OldWorklistSize == worklist.size())
+ return;
+
+ sortWorklist();
+}
+
+void DataflowWorklist::sortWorklist() {
+ std::sort(worklist.begin(), worklist.end(), POV->getComparator());
+}
+
+const CFGBlock *DataflowWorklist::dequeue() {
+ if (worklist.empty())
+ return nullptr;
+ const CFGBlock *b = worklist.pop_back_val();
+ enqueuedBlocks[b->getBlockID()] = false;
+ return b;
+}
+
+namespace {
class LiveVariablesImpl {
public:
AnalysisDeclContext &analysisContext;
@@ -448,18 +502,21 @@ LiveVariables::computeLiveness(AnalysisD
LiveVariablesImpl *LV = new LiveVariablesImpl(AC, killAtAssign);
- // Construct the backward dataflow worklist.
- BackwardDataflowWorklist worklist(*cfg, AC);
+ // Construct the dataflow worklist. Enqueue the exit block as the
+ // start of the analysis.
+ DataflowWorklist worklist(*cfg, AC);
llvm::BitVector everAnalyzedBlock(cfg->getNumBlockIDs());
- llvm::BitVector scannedForAssignments(cfg->getNumBlockIDs());
- while (const CFGBlock *block = worklist.dequeue()) {
+ // FIXME: we should enqueue using post order.
+ for (CFG::const_iterator it = cfg->begin(), ei = cfg->end(); it != ei; ++it) {
+ const CFGBlock *block = *it;
+ worklist.enqueueBlock(block);
// FIXME: Scan for DeclRefExprs using in the LHS of an assignment.
// We need to do this because we lack context in the reverse analysis
// to determine if a DeclRefExpr appears in such a context, and thus
// doesn't constitute a "use".
- if (killAtAssign && !scannedForAssignments[block->getBlockID()]) {
+ if (killAtAssign)
for (CFGBlock::const_iterator bi = block->begin(), be = block->end();
bi != be; ++bi) {
if (Optional<CFGStmt> cs = bi->getAs<CFGStmt>()) {
@@ -474,9 +531,11 @@ LiveVariables::computeLiveness(AnalysisD
}
}
}
- scannedForAssignments[block->getBlockID()] = true;
- }
+ }
+
+ worklist.sortWorklist();
+ while (const CFGBlock *block = worklist.dequeue()) {
// Determine if the block's end value has changed. If not, we
// have nothing left to do for this block.
LivenessValues &prevVal = LV->blocksEndToLiveness[block];
Modified: cfe/trunk/lib/Analysis/PostOrderCFGView.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Analysis/PostOrderCFGView.cpp?rev=218296&r1=218295&r2=218296&view=diff
==============================================================================
--- cfe/trunk/lib/Analysis/PostOrderCFGView.cpp (original)
+++ cfe/trunk/lib/Analysis/PostOrderCFGView.cpp Tue Sep 23 03:34:41 2014
@@ -7,7 +7,7 @@
//
//===----------------------------------------------------------------------===//
//
-// This file implements post order views of the blocks in a CFG.
+// This file implements post order view of the blocks in a CFG.
//
//===----------------------------------------------------------------------===//
@@ -17,16 +17,14 @@ using namespace clang;
void PostOrderCFGView::anchor() { }
-ReversePostOrderCFGView::ReversePostOrderCFGView(const CFG *cfg) {
+PostOrderCFGView::PostOrderCFGView(const CFG *cfg) {
Blocks.reserve(cfg->getNumBlockIDs());
CFGBlockSet BSet(cfg);
-
- typedef llvm::po_iterator<const CFG*, CFGBlockSet, true> po_iterator;
-
+
for (po_iterator I = po_iterator::begin(cfg, BSet),
E = po_iterator::end(cfg, BSet); I != E; ++I) {
+ BlockOrder[*I] = Blocks.size() + 1;
Blocks.push_back(*I);
- BlockOrder[*I] = Blocks.size();
}
}
@@ -49,49 +47,3 @@ bool PostOrderCFGView::BlockOrderCompare
return b1V > b2V;
}
-PostOrderCFGView::PostOrderCFGView(const CFG *cfg) {
- unsigned size = cfg->getNumBlockIDs();
- Blocks.reserve(size);
- CFGBlockSet BSet(cfg);
-
- typedef llvm::po_iterator<const CFG*, CFGBlockSet, true,
- llvm::GraphTraits<llvm::Inverse<const CFG*> >
- > po_iterator;
-
- for (po_iterator I = po_iterator::begin(cfg, BSet),
- E = po_iterator::end(cfg, BSet); I != E; ++I) {
- Blocks.push_back(*I);
- BlockOrder[*I] = Blocks.size();
- }
-
- // It may be that some blocks are inaccessible going from the CFG exit upwards
- // (e.g. infinite loops); we still need to add them.
- for (CFG::const_iterator I = cfg->begin(), E = cfg->end();
- (Blocks.size() < size) && (I != E); ++I) {
- const CFGBlock* block = *I;
- // Add a chain going upwards.
- while (!BlockOrder.count(block)) {
- Blocks.push_back(block);
- BlockOrder[block] = Blocks.size();
- CFGBlock::const_pred_iterator PI = block->pred_begin(),
- PE = block->pred_end();
- for (; PI != PE; ++PI) {
- const CFGBlock* pred = *PI;
- if (pred && !BlockOrder.count(pred)) {
- block = pred;
- break;
- }
- }
- // Chain ends when we couldn't find an unmapped pred.
- if (PI == PE) break;
- }
- }
-}
-
-ReversePostOrderCFGView *
-ReversePostOrderCFGView::create(AnalysisDeclContext &ctx) {
- const CFG *cfg = ctx.getCFG();
- if (!cfg)
- return nullptr;
- return new ReversePostOrderCFGView(cfg);
-}
Modified: cfe/trunk/lib/Analysis/UninitializedValues.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Analysis/UninitializedValues.cpp?rev=218296&r1=218295&r2=218296&view=diff
==============================================================================
--- cfe/trunk/lib/Analysis/UninitializedValues.cpp (original)
+++ cfe/trunk/lib/Analysis/UninitializedValues.cpp Tue Sep 23 03:34:41 2014
@@ -15,7 +15,7 @@
#include "clang/AST/Attr.h"
#include "clang/AST/Decl.h"
#include "clang/AST/StmtVisitor.h"
-#include "clang/Analysis/Analyses/DataflowWorklist.h"
+#include "clang/Analysis/Analyses/PostOrderCFGView.h"
#include "clang/Analysis/Analyses/UninitializedValues.h"
#include "clang/Analysis/AnalysisContext.h"
#include "clang/Analysis/CFG.h"
@@ -199,6 +199,66 @@ ValueVector::reference CFGBlockValues::o
}
//------------------------------------------------------------------------====//
+// Worklist: worklist for dataflow analysis.
+//====------------------------------------------------------------------------//
+
+namespace {
+class DataflowWorklist {
+ PostOrderCFGView::iterator PO_I, PO_E;
+ SmallVector<const CFGBlock *, 20> worklist;
+ llvm::BitVector enqueuedBlocks;
+public:
+ DataflowWorklist(const CFG &cfg, PostOrderCFGView &view)
+ : PO_I(view.begin()), PO_E(view.end()),
+ enqueuedBlocks(cfg.getNumBlockIDs(), true) {
+ // Treat the first block as already analyzed.
+ if (PO_I != PO_E) {
+ assert(*PO_I == &cfg.getEntry());
+ enqueuedBlocks[(*PO_I)->getBlockID()] = false;
+ ++PO_I;
+ }
+ }
+
+ void enqueueSuccessors(const CFGBlock *block);
+ const CFGBlock *dequeue();
+};
+}
+
+void DataflowWorklist::enqueueSuccessors(const clang::CFGBlock *block) {
+ for (CFGBlock::const_succ_iterator I = block->succ_begin(),
+ E = block->succ_end(); I != E; ++I) {
+ const CFGBlock *Successor = *I;
+ if (!Successor || enqueuedBlocks[Successor->getBlockID()])
+ continue;
+ worklist.push_back(Successor);
+ enqueuedBlocks[Successor->getBlockID()] = true;
+ }
+}
+
+const CFGBlock *DataflowWorklist::dequeue() {
+ const CFGBlock *B = nullptr;
+
+ // First dequeue from the worklist. This can represent
+ // updates along backedges that we want propagated as quickly as possible.
+ if (!worklist.empty())
+ B = worklist.pop_back_val();
+
+ // Next dequeue from the initial reverse post order. This is the
+ // theoretical ideal in the presence of no back edges.
+ else if (PO_I != PO_E) {
+ B = *PO_I;
+ ++PO_I;
+ }
+ else {
+ return nullptr;
+ }
+
+ assert(enqueuedBlocks[B->getBlockID()] == true);
+ enqueuedBlocks[B->getBlockID()] = false;
+ return B;
+}
+
+//------------------------------------------------------------------------====//
// Classification of DeclRefExprs as use or initialization.
//====------------------------------------------------------------------------//
@@ -796,7 +856,7 @@ void clang::runUninitializedVariablesAna
}
// Proceed with the workist.
- ForwardDataflowWorklist worklist(cfg, ac);
+ DataflowWorklist worklist(cfg, *ac.getAnalysis<PostOrderCFGView>());
llvm::BitVector previouslyVisited(cfg.getNumBlockIDs());
worklist.enqueueSuccessors(&cfg.getEntry());
llvm::BitVector wasAnalyzed(cfg.getNumBlockIDs(), false);
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