260 lines
10 KiB
C++
260 lines
10 KiB
C++
//===- LexicalScopes.cpp - Collecting lexical scope info --------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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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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#ifndef LLVM_CODEGEN_LEXICALSCOPES_H
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#define LLVM_CODEGEN_LEXICALSCOPES_H
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#include "llvm/ADT/ArrayRef.h"
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/ADT/SmallPtrSet.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/IR/DebugInfoMetadata.h"
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#include <cassert>
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#include <unordered_map>
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#include <utility>
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namespace llvm {
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class MachineBasicBlock;
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class MachineFunction;
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class MachineInstr;
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class MDNode;
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//===----------------------------------------------------------------------===//
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/// InsnRange - This is used to track range of instructions with identical
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/// lexical scope.
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///
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using InsnRange = std::pair<const MachineInstr *, const MachineInstr *>;
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//===----------------------------------------------------------------------===//
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/// LexicalScope - This class is used to track scope information.
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///
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class LexicalScope {
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public:
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LexicalScope(LexicalScope *P, const DILocalScope *D, const DILocation *I,
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bool A)
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: Parent(P), Desc(D), InlinedAtLocation(I), AbstractScope(A) {
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assert(D);
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assert(D->getSubprogram()->getUnit()->getEmissionKind() !=
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DICompileUnit::NoDebug &&
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"Don't build lexical scopes for non-debug locations");
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assert(D->isResolved() && "Expected resolved node");
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assert((!I || I->isResolved()) && "Expected resolved node");
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if (Parent)
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Parent->addChild(this);
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}
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// Accessors.
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LexicalScope *getParent() const { return Parent; }
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const MDNode *getDesc() const { return Desc; }
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const DILocation *getInlinedAt() const { return InlinedAtLocation; }
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const DILocalScope *getScopeNode() const { return Desc; }
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bool isAbstractScope() const { return AbstractScope; }
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SmallVectorImpl<LexicalScope *> &getChildren() { return Children; }
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SmallVectorImpl<InsnRange> &getRanges() { return Ranges; }
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/// addChild - Add a child scope.
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void addChild(LexicalScope *S) { Children.push_back(S); }
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/// openInsnRange - This scope covers instruction range starting from MI.
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void openInsnRange(const MachineInstr *MI) {
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if (!FirstInsn)
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FirstInsn = MI;
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if (Parent)
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Parent->openInsnRange(MI);
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}
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/// extendInsnRange - Extend the current instruction range covered by
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/// this scope.
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void extendInsnRange(const MachineInstr *MI) {
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assert(FirstInsn && "MI Range is not open!");
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LastInsn = MI;
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if (Parent)
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Parent->extendInsnRange(MI);
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}
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/// closeInsnRange - Create a range based on FirstInsn and LastInsn collected
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/// until now. This is used when a new scope is encountered while walking
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/// machine instructions.
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void closeInsnRange(LexicalScope *NewScope = nullptr) {
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assert(LastInsn && "Last insn missing!");
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Ranges.push_back(InsnRange(FirstInsn, LastInsn));
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FirstInsn = nullptr;
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LastInsn = nullptr;
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// If Parent dominates NewScope then do not close Parent's instruction
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// range.
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if (Parent && (!NewScope || !Parent->dominates(NewScope)))
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Parent->closeInsnRange(NewScope);
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}
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/// dominates - Return true if current scope dominates given lexical scope.
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bool dominates(const LexicalScope *S) const {
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if (S == this)
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return true;
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if (DFSIn < S->getDFSIn() && DFSOut > S->getDFSOut())
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return true;
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return false;
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}
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// Depth First Search support to walk and manipulate LexicalScope hierarchy.
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unsigned getDFSOut() const { return DFSOut; }
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void setDFSOut(unsigned O) { DFSOut = O; }
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unsigned getDFSIn() const { return DFSIn; }
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void setDFSIn(unsigned I) { DFSIn = I; }
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/// dump - print lexical scope.
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void dump(unsigned Indent = 0) const;
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private:
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LexicalScope *Parent; // Parent to this scope.
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const DILocalScope *Desc; // Debug info descriptor.
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const DILocation *InlinedAtLocation; // Location at which this
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// scope is inlined.
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bool AbstractScope; // Abstract Scope
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SmallVector<LexicalScope *, 4> Children; // Scopes defined in scope.
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// Contents not owned.
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SmallVector<InsnRange, 4> Ranges;
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const MachineInstr *LastInsn = nullptr; // Last instruction of this scope.
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const MachineInstr *FirstInsn = nullptr; // First instruction of this scope.
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unsigned DFSIn = 0; // In & Out Depth use to determine scope nesting.
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unsigned DFSOut = 0;
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};
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//===----------------------------------------------------------------------===//
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/// LexicalScopes - This class provides interface to collect and use lexical
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/// scoping information from machine instruction.
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///
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class LexicalScopes {
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public:
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LexicalScopes() = default;
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/// initialize - Scan machine function and constuct lexical scope nest, resets
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/// the instance if necessary.
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void initialize(const MachineFunction &);
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/// releaseMemory - release memory.
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void reset();
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/// empty - Return true if there is any lexical scope information available.
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bool empty() { return CurrentFnLexicalScope == nullptr; }
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/// getCurrentFunctionScope - Return lexical scope for the current function.
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LexicalScope *getCurrentFunctionScope() const {
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return CurrentFnLexicalScope;
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}
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/// getMachineBasicBlocks - Populate given set using machine basic blocks
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/// which have machine instructions that belong to lexical scope identified by
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/// DebugLoc.
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void getMachineBasicBlocks(const DILocation *DL,
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SmallPtrSetImpl<const MachineBasicBlock *> &MBBs);
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/// Return true if DebugLoc's lexical scope dominates at least one machine
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/// instruction's lexical scope in a given machine basic block.
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bool dominates(const DILocation *DL, MachineBasicBlock *MBB);
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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 *findLexicalScope(const DILocation *DL);
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/// getAbstractScopesList - Return a reference to list of abstract scopes.
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ArrayRef<LexicalScope *> getAbstractScopesList() const {
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return AbstractScopesList;
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}
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/// findAbstractScope - Find an abstract scope or return null.
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LexicalScope *findAbstractScope(const DILocalScope *N) {
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auto I = AbstractScopeMap.find(N);
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return I != AbstractScopeMap.end() ? &I->second : nullptr;
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}
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/// findInlinedScope - Find an inlined scope for the given scope/inlined-at.
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LexicalScope *findInlinedScope(const DILocalScope *N, const DILocation *IA) {
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auto I = InlinedLexicalScopeMap.find(std::make_pair(N, IA));
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return I != InlinedLexicalScopeMap.end() ? &I->second : nullptr;
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}
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/// findLexicalScope - Find regular lexical scope or return null.
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LexicalScope *findLexicalScope(const DILocalScope *N) {
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auto I = LexicalScopeMap.find(N);
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return I != LexicalScopeMap.end() ? &I->second : nullptr;
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}
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/// getOrCreateAbstractScope - Find or create an abstract lexical scope.
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LexicalScope *getOrCreateAbstractScope(const DILocalScope *Scope);
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private:
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/// getOrCreateLexicalScope - Find lexical scope for the given Scope/IA. If
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/// not available then create new lexical scope.
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LexicalScope *getOrCreateLexicalScope(const DILocalScope *Scope,
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const DILocation *IA = nullptr);
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LexicalScope *getOrCreateLexicalScope(const DILocation *DL) {
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return DL ? getOrCreateLexicalScope(DL->getScope(), DL->getInlinedAt())
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: nullptr;
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}
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/// getOrCreateRegularScope - Find or create a regular lexical scope.
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LexicalScope *getOrCreateRegularScope(const DILocalScope *Scope);
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/// getOrCreateInlinedScope - Find or create an inlined lexical scope.
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LexicalScope *getOrCreateInlinedScope(const DILocalScope *Scope,
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const DILocation *InlinedAt);
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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 extractLexicalScopes(SmallVectorImpl<InsnRange> &MIRanges,
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DenseMap<const MachineInstr *, LexicalScope *> &M);
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void constructScopeNest(LexicalScope *Scope);
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void
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assignInstructionRanges(SmallVectorImpl<InsnRange> &MIRanges,
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DenseMap<const MachineInstr *, LexicalScope *> &M);
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const MachineFunction *MF = nullptr;
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/// LexicalScopeMap - Tracks the scopes in the current function.
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// Use an unordered_map to ensure value pointer validity over insertion.
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std::unordered_map<const DILocalScope *, LexicalScope> LexicalScopeMap;
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/// InlinedLexicalScopeMap - Tracks inlined function scopes in current
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/// function.
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std::unordered_map<std::pair<const DILocalScope *, const DILocation *>,
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LexicalScope,
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pair_hash<const DILocalScope *, const DILocation *>>
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InlinedLexicalScopeMap;
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/// AbstractScopeMap - These scopes are not included LexicalScopeMap.
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// Use an unordered_map to ensure value pointer validity over insertion.
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std::unordered_map<const DILocalScope *, LexicalScope> AbstractScopeMap;
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/// AbstractScopesList - Tracks abstract scopes constructed while processing
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/// a function.
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SmallVector<LexicalScope *, 4> AbstractScopesList;
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/// CurrentFnLexicalScope - Top level scope for the current function.
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///
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LexicalScope *CurrentFnLexicalScope = nullptr;
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/// Map a location to the set of basic blocks it dominates. This is a cache
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/// for \ref LexicalScopes::getMachineBasicBlocks results.
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using BlockSetT = SmallPtrSet<const MachineBasicBlock *, 4>;
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DenseMap<const DILocation *, std::unique_ptr<BlockSetT>> DominatedBlocks;
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};
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} // end namespace llvm
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#endif // LLVM_CODEGEN_LEXICALSCOPES_H
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