338 lines
11 KiB
C++
338 lines
11 KiB
C++
//===- LexicalScopes.cpp - Collecting lexical scope info ------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements LexicalScopes analysis.
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//
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// This pass collects lexical scope information and maps machine instructions
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// to respective lexical scopes.
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//
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "lexicalscopes"
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#include "llvm/CodeGen/LexicalScopes.h"
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#include "llvm/Function.h"
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#include "llvm/Analysis/DebugInfo.h"
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#include "llvm/CodeGen/MachineFunction.h"
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#include "llvm/CodeGen/MachineInstr.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/FormattedStream.h"
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using namespace llvm;
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LexicalScopes::~LexicalScopes() {
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releaseMemory();
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}
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/// releaseMemory - release memory.
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void LexicalScopes::releaseMemory() {
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MF = NULL;
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CurrentFnLexicalScope = NULL;
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DeleteContainerSeconds(LexicalScopeMap);
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DeleteContainerSeconds(AbstractScopeMap);
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InlinedLexicalScopeMap.clear();
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AbstractScopesList.clear();
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}
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/// initialize - Scan machine function and constuct lexical scope nest.
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void LexicalScopes::initialize(const MachineFunction &Fn) {
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releaseMemory();
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MF = &Fn;
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SmallVector<InsnRange, 4> MIRanges;
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DenseMap<const MachineInstr *, LexicalScope *> MI2ScopeMap;
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extractLexicalScopes(MIRanges, MI2ScopeMap);
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if (CurrentFnLexicalScope) {
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constructScopeNest(CurrentFnLexicalScope);
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assignInstructionRanges(MIRanges, MI2ScopeMap);
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}
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}
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/// extractLexicalScopes - Extract instruction ranges for each lexical scopes
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/// for the given machine function.
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void LexicalScopes::
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extractLexicalScopes(SmallVectorImpl<InsnRange> &MIRanges,
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DenseMap<const MachineInstr *, LexicalScope *> &MI2ScopeMap) {
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// Scan each instruction and create scopes. First build working set of scopes.
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for (MachineFunction::const_iterator I = MF->begin(), E = MF->end();
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I != E; ++I) {
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const MachineInstr *RangeBeginMI = NULL;
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const MachineInstr *PrevMI = NULL;
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DebugLoc PrevDL;
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for (MachineBasicBlock::const_iterator II = I->begin(), IE = I->end();
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II != IE; ++II) {
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const MachineInstr *MInsn = II;
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// Check if instruction has valid location information.
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const DebugLoc MIDL = MInsn->getDebugLoc();
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if (MIDL.isUnknown()) {
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PrevMI = MInsn;
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continue;
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}
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// If scope has not changed then skip this instruction.
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if (MIDL == PrevDL) {
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PrevMI = MInsn;
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continue;
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}
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// Ignore DBG_VALUE. It does not contribute to any instruction in output.
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if (MInsn->isDebugValue())
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continue;
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if (RangeBeginMI) {
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// If we have already seen a beginning of an instruction range and
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// current instruction scope does not match scope of first instruction
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// in this range then create a new instruction range.
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InsnRange R(RangeBeginMI, PrevMI);
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MI2ScopeMap[RangeBeginMI] = getOrCreateLexicalScope(PrevDL);
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MIRanges.push_back(R);
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}
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// This is a beginning of a new instruction range.
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RangeBeginMI = MInsn;
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// Reset previous markers.
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PrevMI = MInsn;
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PrevDL = MIDL;
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}
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// Create last instruction range.
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if (RangeBeginMI && PrevMI && !PrevDL.isUnknown()) {
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InsnRange R(RangeBeginMI, PrevMI);
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MIRanges.push_back(R);
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MI2ScopeMap[RangeBeginMI] = getOrCreateLexicalScope(PrevDL);
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}
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}
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}
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/// findLexicalScope - Find lexical scope, either regular or inlined, for the
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/// given DebugLoc. Return NULL if not found.
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LexicalScope *LexicalScopes::findLexicalScope(DebugLoc DL) {
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MDNode *Scope = NULL;
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MDNode *IA = NULL;
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DL.getScopeAndInlinedAt(Scope, IA, MF->getFunction()->getContext());
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if (!Scope) return NULL;
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// The scope that we were created with could have an extra file - which
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// isn't what we care about in this case.
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DIDescriptor D = DIDescriptor(Scope);
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if (D.isLexicalBlockFile())
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Scope = DILexicalBlockFile(Scope).getScope();
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if (IA)
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return InlinedLexicalScopeMap.lookup(DebugLoc::getFromDILocation(IA));
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return LexicalScopeMap.lookup(Scope);
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}
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/// getOrCreateLexicalScope - Find lexical scope for the given DebugLoc. If
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/// not available then create new lexical scope.
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LexicalScope *LexicalScopes::getOrCreateLexicalScope(DebugLoc DL) {
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MDNode *Scope = NULL;
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MDNode *InlinedAt = NULL;
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DL.getScopeAndInlinedAt(Scope, InlinedAt, MF->getFunction()->getContext());
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if (InlinedAt) {
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// Create an abstract scope for inlined function.
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getOrCreateAbstractScope(Scope);
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// Create an inlined scope for inlined function.
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return getOrCreateInlinedScope(Scope, InlinedAt);
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}
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return getOrCreateRegularScope(Scope);
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}
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/// getOrCreateRegularScope - Find or create a regular lexical scope.
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LexicalScope *LexicalScopes::getOrCreateRegularScope(MDNode *Scope) {
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DIDescriptor D = DIDescriptor(Scope);
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if (D.isLexicalBlockFile()) {
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Scope = DILexicalBlockFile(Scope).getScope();
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D = DIDescriptor(Scope);
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}
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LexicalScope *WScope = LexicalScopeMap.lookup(Scope);
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if (WScope)
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return WScope;
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LexicalScope *Parent = NULL;
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if (D.isLexicalBlock())
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Parent = getOrCreateLexicalScope(DebugLoc::getFromDILexicalBlock(Scope));
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WScope = new LexicalScope(Parent, DIDescriptor(Scope), NULL, false);
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LexicalScopeMap.insert(std::make_pair(Scope, WScope));
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if (!Parent && DIDescriptor(Scope).isSubprogram()
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&& DISubprogram(Scope).describes(MF->getFunction()))
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CurrentFnLexicalScope = WScope;
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return WScope;
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}
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/// getOrCreateInlinedScope - Find or create an inlined lexical scope.
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LexicalScope *LexicalScopes::getOrCreateInlinedScope(MDNode *Scope,
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MDNode *InlinedAt) {
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LexicalScope *InlinedScope = LexicalScopeMap.lookup(InlinedAt);
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if (InlinedScope)
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return InlinedScope;
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DebugLoc InlinedLoc = DebugLoc::getFromDILocation(InlinedAt);
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InlinedScope = new LexicalScope(getOrCreateLexicalScope(InlinedLoc),
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DIDescriptor(Scope), InlinedAt, false);
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InlinedLexicalScopeMap[InlinedLoc] = InlinedScope;
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LexicalScopeMap[InlinedAt] = InlinedScope;
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return InlinedScope;
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}
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/// getOrCreateAbstractScope - Find or create an abstract lexical scope.
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LexicalScope *LexicalScopes::getOrCreateAbstractScope(const MDNode *N) {
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assert(N && "Invalid Scope encoding!");
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DIDescriptor Scope(N);
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if (Scope.isLexicalBlockFile())
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Scope = DILexicalBlockFile(Scope).getScope();
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LexicalScope *AScope = AbstractScopeMap.lookup(N);
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if (AScope)
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return AScope;
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LexicalScope *Parent = NULL;
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if (Scope.isLexicalBlock()) {
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DILexicalBlock DB(N);
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DIDescriptor ParentDesc = DB.getContext();
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Parent = getOrCreateAbstractScope(ParentDesc);
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}
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AScope = new LexicalScope(Parent, DIDescriptor(N), NULL, true);
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AbstractScopeMap[N] = AScope;
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if (DIDescriptor(N).isSubprogram())
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AbstractScopesList.push_back(AScope);
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return AScope;
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}
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/// constructScopeNest
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void LexicalScopes::constructScopeNest(LexicalScope *Scope) {
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assert (Scope && "Unable to calculate scop edominance graph!");
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SmallVector<LexicalScope *, 4> WorkStack;
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WorkStack.push_back(Scope);
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unsigned Counter = 0;
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while (!WorkStack.empty()) {
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LexicalScope *WS = WorkStack.back();
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const SmallVector<LexicalScope *, 4> &Children = WS->getChildren();
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bool visitedChildren = false;
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for (SmallVector<LexicalScope *, 4>::const_iterator SI = Children.begin(),
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SE = Children.end(); SI != SE; ++SI) {
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LexicalScope *ChildScope = *SI;
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if (!ChildScope->getDFSOut()) {
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WorkStack.push_back(ChildScope);
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visitedChildren = true;
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ChildScope->setDFSIn(++Counter);
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break;
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}
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}
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if (!visitedChildren) {
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WorkStack.pop_back();
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WS->setDFSOut(++Counter);
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}
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}
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}
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/// assignInstructionRanges - Find ranges of instructions covered by each
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/// lexical scope.
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void LexicalScopes::
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assignInstructionRanges(SmallVectorImpl<InsnRange> &MIRanges,
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DenseMap<const MachineInstr *, LexicalScope *> &MI2ScopeMap)
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{
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LexicalScope *PrevLexicalScope = NULL;
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for (SmallVectorImpl<InsnRange>::const_iterator RI = MIRanges.begin(),
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RE = MIRanges.end(); RI != RE; ++RI) {
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const InsnRange &R = *RI;
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LexicalScope *S = MI2ScopeMap.lookup(R.first);
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assert (S && "Lost LexicalScope for a machine instruction!");
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if (PrevLexicalScope && !PrevLexicalScope->dominates(S))
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PrevLexicalScope->closeInsnRange(S);
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S->openInsnRange(R.first);
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S->extendInsnRange(R.second);
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PrevLexicalScope = S;
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}
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if (PrevLexicalScope)
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PrevLexicalScope->closeInsnRange();
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}
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/// getMachineBasicBlocks - Populate given set using machine basic blocks which
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/// have machine instructions that belong to lexical scope identified by
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/// DebugLoc.
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void LexicalScopes::
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getMachineBasicBlocks(DebugLoc DL,
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SmallPtrSet<const MachineBasicBlock*, 4> &MBBs) {
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MBBs.clear();
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LexicalScope *Scope = getOrCreateLexicalScope(DL);
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if (!Scope)
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return;
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if (Scope == CurrentFnLexicalScope) {
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for (MachineFunction::const_iterator I = MF->begin(), E = MF->end();
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I != E; ++I)
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MBBs.insert(I);
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return;
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}
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SmallVector<InsnRange, 4> &InsnRanges = Scope->getRanges();
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for (SmallVector<InsnRange, 4>::iterator I = InsnRanges.begin(),
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E = InsnRanges.end(); I != E; ++I) {
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InsnRange &R = *I;
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MBBs.insert(R.first->getParent());
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}
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}
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/// dominates - Return true if DebugLoc's lexical scope dominates at least one
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/// machine instruction's lexical scope in a given machine basic block.
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bool LexicalScopes::dominates(DebugLoc DL, MachineBasicBlock *MBB) {
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LexicalScope *Scope = getOrCreateLexicalScope(DL);
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if (!Scope)
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return false;
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// Current function scope covers all basic blocks in the function.
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if (Scope == CurrentFnLexicalScope && MBB->getParent() == MF)
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return true;
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bool Result = false;
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for (MachineBasicBlock::iterator I = MBB->begin(), E = MBB->end();
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I != E; ++I) {
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DebugLoc IDL = I->getDebugLoc();
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if (IDL.isUnknown())
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continue;
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if (LexicalScope *IScope = getOrCreateLexicalScope(IDL))
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if (Scope->dominates(IScope))
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return true;
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}
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return Result;
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}
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void LexicalScope::anchor() { }
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/// dump - Print data structures.
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void LexicalScope::dump() const {
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#ifndef NDEBUG
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raw_ostream &err = dbgs();
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err.indent(IndentLevel);
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err << "DFSIn: " << DFSIn << " DFSOut: " << DFSOut << "\n";
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const MDNode *N = Desc;
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N->dump();
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if (AbstractScope)
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err << "Abstract Scope\n";
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IndentLevel += 2;
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if (!Children.empty())
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err << "Children ...\n";
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for (unsigned i = 0, e = Children.size(); i != e; ++i)
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if (Children[i] != this)
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Children[i]->dump();
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IndentLevel -= 2;
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#endif
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}
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