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thirdparty/capstone/suite/synctools/tablegen/include/llvm/CodeGen/LexicalScopes.h

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