1 //===- LexicalScopes.cpp - Collecting lexical scope info ------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements LexicalScopes analysis.
12 // This pass collects lexical scope information and maps machine instructions
13 // to respective lexical scopes.
15 //===----------------------------------------------------------------------===//
17 #define DEBUG_TYPE "lexicalscopes"
18 #include "llvm/CodeGen/LexicalScopes.h"
19 #include "llvm/Function.h"
20 #include "llvm/Analysis/DebugInfo.h"
21 #include "llvm/CodeGen/MachineFunction.h"
22 #include "llvm/CodeGen/MachineInstr.h"
23 #include "llvm/Support/Debug.h"
24 #include "llvm/Support/ErrorHandling.h"
25 #include "llvm/Support/FormattedStream.h"
28 LexicalScopes::~LexicalScopes() {
32 /// releaseMemory - release memory.
33 void LexicalScopes::releaseMemory() {
35 CurrentFnLexicalScope = NULL;
36 DeleteContainerSeconds(LexicalScopeMap);
37 DeleteContainerSeconds(AbstractScopeMap);
38 InlinedLexicalScopeMap.clear();
39 AbstractScopesList.clear();
42 /// initialize - Scan machine function and constuct lexical scope nest.
43 void LexicalScopes::initialize(const MachineFunction &Fn) {
46 SmallVector<InsnRange, 4> MIRanges;
47 DenseMap<const MachineInstr *, LexicalScope *> MI2ScopeMap;
48 extractLexicalScopes(MIRanges, MI2ScopeMap);
49 if (CurrentFnLexicalScope) {
50 constructScopeNest(CurrentFnLexicalScope);
51 assignInstructionRanges(MIRanges, MI2ScopeMap);
55 /// extractLexicalScopes - Extract instruction ranges for each lexical scopes
56 /// for the given machine function.
58 extractLexicalScopes(SmallVectorImpl<InsnRange> &MIRanges,
59 DenseMap<const MachineInstr *, LexicalScope *> &MI2ScopeMap) {
61 // Scan each instruction and create scopes. First build working set of scopes.
62 for (MachineFunction::const_iterator I = MF->begin(), E = MF->end();
64 const MachineInstr *RangeBeginMI = NULL;
65 const MachineInstr *PrevMI = NULL;
67 for (MachineBasicBlock::const_iterator II = I->begin(), IE = I->end();
69 const MachineInstr *MInsn = II;
71 // Check if instruction has valid location information.
72 const DebugLoc MIDL = MInsn->getDebugLoc();
73 if (MIDL.isUnknown()) {
78 // If scope has not changed then skip this instruction.
84 // Ignore DBG_VALUE. It does not contribute to any instruction in output.
85 if (MInsn->isDebugValue())
89 // If we have already seen a beginning of an instruction range and
90 // current instruction scope does not match scope of first instruction
91 // in this range then create a new instruction range.
92 InsnRange R(RangeBeginMI, PrevMI);
93 MI2ScopeMap[RangeBeginMI] = getOrCreateLexicalScope(PrevDL);
94 MIRanges.push_back(R);
97 // This is a beginning of a new instruction range.
100 // Reset previous markers.
105 // Create last instruction range.
106 if (RangeBeginMI && PrevMI && !PrevDL.isUnknown()) {
107 InsnRange R(RangeBeginMI, PrevMI);
108 MIRanges.push_back(R);
109 MI2ScopeMap[RangeBeginMI] = getOrCreateLexicalScope(PrevDL);
114 /// findLexicalScope - Find lexical scope, either regular or inlined, for the
115 /// given DebugLoc. Return NULL if not found.
116 LexicalScope *LexicalScopes::findLexicalScope(DebugLoc DL) {
117 MDNode *Scope = NULL;
119 DL.getScopeAndInlinedAt(Scope, IA, MF->getFunction()->getContext());
120 if (!Scope) return NULL;
122 return InlinedLexicalScopeMap.lookup(DebugLoc::getFromDILocation(IA));
123 return LexicalScopeMap.lookup(DL.getScope(Scope->getContext()));
126 /// getOrCreateLexicalScope - Find lexical scope for the given DebugLoc. If
127 /// not available then create new lexical scope.
128 LexicalScope *LexicalScopes::getOrCreateLexicalScope(DebugLoc DL) {
129 MDNode *Scope = NULL;
130 MDNode *InlinedAt = NULL;
131 DL.getScopeAndInlinedAt(Scope, InlinedAt, MF->getFunction()->getContext());
133 // Create an abstract scope for inlined function.
134 getOrCreateAbstractScope(Scope);
135 // Create an inlined scope for inlined function.
136 return getOrCreateInlinedScope(Scope, InlinedAt);
139 return getOrCreateRegularScope(Scope);
142 /// getOrCreateRegularScope - Find or create a regular lexical scope.
143 LexicalScope *LexicalScopes::getOrCreateRegularScope(MDNode *Scope) {
144 LexicalScope *WScope = LexicalScopeMap.lookup(Scope);
148 LexicalScope *Parent = NULL;
149 if (DIDescriptor(Scope).isLexicalBlock())
150 Parent = getOrCreateLexicalScope(DebugLoc::getFromDILexicalBlock(Scope));
151 WScope = new LexicalScope(Parent, DIDescriptor(Scope), NULL, false);
152 LexicalScopeMap.insert(std::make_pair(Scope, WScope));
153 if (!Parent && DIDescriptor(Scope).isSubprogram()
154 && DISubprogram(Scope).describes(MF->getFunction()))
155 CurrentFnLexicalScope = WScope;
160 /// getOrCreateInlinedScope - Find or create an inlined lexical scope.
161 LexicalScope *LexicalScopes::getOrCreateInlinedScope(MDNode *Scope,
163 LexicalScope *InlinedScope = LexicalScopeMap.lookup(InlinedAt);
167 DebugLoc InlinedLoc = DebugLoc::getFromDILocation(InlinedAt);
168 InlinedScope = new LexicalScope(getOrCreateLexicalScope(InlinedLoc),
169 DIDescriptor(Scope), InlinedAt, false);
170 InlinedLexicalScopeMap[InlinedLoc] = InlinedScope;
171 LexicalScopeMap[InlinedAt] = InlinedScope;
175 /// getOrCreateAbstractScope - Find or create an abstract lexical scope.
176 LexicalScope *LexicalScopes::getOrCreateAbstractScope(const MDNode *N) {
177 assert(N && "Invalid Scope encoding!");
179 LexicalScope *AScope = AbstractScopeMap.lookup(N);
183 LexicalScope *Parent = NULL;
184 DIDescriptor Scope(N);
185 if (Scope.isLexicalBlock()) {
186 DILexicalBlock DB(N);
187 DIDescriptor ParentDesc = DB.getContext();
188 Parent = getOrCreateAbstractScope(ParentDesc);
190 AScope = new LexicalScope(Parent, DIDescriptor(N), NULL, true);
191 AbstractScopeMap[N] = AScope;
192 if (DIDescriptor(N).isSubprogram())
193 AbstractScopesList.push_back(AScope);
197 /// constructScopeNest
198 void LexicalScopes::constructScopeNest(LexicalScope *Scope) {
199 assert (Scope && "Unable to calculate scop edominance graph!");
200 SmallVector<LexicalScope *, 4> WorkStack;
201 WorkStack.push_back(Scope);
202 unsigned Counter = 0;
203 while (!WorkStack.empty()) {
204 LexicalScope *WS = WorkStack.back();
205 const SmallVector<LexicalScope *, 4> &Children = WS->getChildren();
206 bool visitedChildren = false;
207 for (SmallVector<LexicalScope *, 4>::const_iterator SI = Children.begin(),
208 SE = Children.end(); SI != SE; ++SI) {
209 LexicalScope *ChildScope = *SI;
210 if (!ChildScope->getDFSOut()) {
211 WorkStack.push_back(ChildScope);
212 visitedChildren = true;
213 ChildScope->setDFSIn(++Counter);
217 if (!visitedChildren) {
218 WorkStack.pop_back();
219 WS->setDFSOut(++Counter);
224 /// assignInstructionRanges - Find ranges of instructions covered by each
227 assignInstructionRanges(SmallVectorImpl<InsnRange> &MIRanges,
228 DenseMap<const MachineInstr *, LexicalScope *> &MI2ScopeMap)
231 LexicalScope *PrevLexicalScope = NULL;
232 for (SmallVectorImpl<InsnRange>::const_iterator RI = MIRanges.begin(),
233 RE = MIRanges.end(); RI != RE; ++RI) {
234 const InsnRange &R = *RI;
235 LexicalScope *S = MI2ScopeMap.lookup(R.first);
236 assert (S && "Lost LexicalScope for a machine instruction!");
237 if (PrevLexicalScope && !PrevLexicalScope->dominates(S))
238 PrevLexicalScope->closeInsnRange(S);
239 S->openInsnRange(R.first);
240 S->extendInsnRange(R.second);
241 PrevLexicalScope = S;
244 if (PrevLexicalScope)
245 PrevLexicalScope->closeInsnRange();
248 /// getMachineBasicBlocks - Populate given set using machine basic blocks which
249 /// have machine instructions that belong to lexical scope identified by
252 getMachineBasicBlocks(DebugLoc DL,
253 SmallPtrSet<const MachineBasicBlock*, 4> &MBBs) {
255 LexicalScope *Scope = getOrCreateLexicalScope(DL);
259 if (Scope == CurrentFnLexicalScope) {
260 for (MachineFunction::const_iterator I = MF->begin(), E = MF->end();
266 SmallVector<InsnRange, 4> &InsnRanges = Scope->getRanges();
267 for (SmallVector<InsnRange, 4>::iterator I = InsnRanges.begin(),
268 E = InsnRanges.end(); I != E; ++I) {
270 MBBs.insert(R.first->getParent());
274 /// dominates - Return true if DebugLoc's lexical scope dominates at least one
275 /// machine instruction's lexical scope in a given machine basic block.
276 bool LexicalScopes::dominates(DebugLoc DL, MachineBasicBlock *MBB) {
277 LexicalScope *Scope = getOrCreateLexicalScope(DL);
281 // Current function scope covers all basic blocks in the function.
282 if (Scope == CurrentFnLexicalScope && MBB->getParent() == MF)
286 for (MachineBasicBlock::iterator I = MBB->begin(), E = MBB->end();
288 DebugLoc IDL = I->getDebugLoc();
291 if (LexicalScope *IScope = getOrCreateLexicalScope(IDL))
292 if (Scope->dominates(IScope))
298 /// dump - Print data structures.
299 void LexicalScope::dump() const {
301 raw_ostream &err = dbgs();
302 err.indent(IndentLevel);
303 err << "DFSIn: " << DFSIn << " DFSOut: " << DFSOut << "\n";
304 const MDNode *N = Desc;
307 err << "Abstract Scope\n";
310 if (!Children.empty())
311 err << "Children ...\n";
312 for (unsigned i = 0, e = Children.size(); i != e; ++i)
313 if (Children[i] != this)