//===--- SILDebugScope.h - DebugScopes for SIL code -------------*- C++ -*-===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2016 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See http://swift.org/LICENSE.txt for license information
// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
//
// This file defines a container for scope information used to
// generate debug info.
//
//===----------------------------------------------------------------------===//

#ifndef SWIFT_SIL_DEBUGSCOPE_H
#define SWIFT_SIL_DEBUGSCOPE_H

#include "swift/SIL/SILAllocated.h"
#include "swift/SIL/SILLocation.h"

namespace swift {

class SILDebugLocation;
class SILDebugScope;
class SILFunction;
class SILInstruction;

/// This class stores a lexical scope as it is represented in the
/// debug info. In contrast to LLVM IR, SILDebugScope also holds all
/// the inlining information. In LLVM IR the inline info is part of
/// DILocation.
class SILDebugScope : public SILAllocated<SILDebugScope> {
public:
  /// The AST node this lexical scope represents.
  SILLocation Loc;
  /// Always points to the parent lexical scope.
  /// For top-level scopes, this is the SILFunction.
  PointerUnion<const SILDebugScope *, SILFunction *> Parent;
  /// An optional chain of inlined call sites.
  ///
  /// If this scope is inlined, this points to a special "scope" that
  /// holds only the location of the call site. The parent scope will be
  /// the scope of the inlined call site.
  ///
  /// Note that compared to the inlinedAt chain in llvm::DILocation
  /// SILDebugScope represents an inline tree.
  const SILDebugScope *InlinedCallSite;

  SILDebugScope(SILLocation Loc, SILFunction *SILFn,
                const SILDebugScope *ParentScope = nullptr,
                const SILDebugScope *InlinedCallSite = nullptr)
      : Loc(Loc), InlinedCallSite(InlinedCallSite) {
    if (ParentScope)
      Parent = ParentScope;
    else {
      assert(SILFn && "no parent provided");
      Parent = SILFn;
    }
  }

  /// Create a scope for an artificial function.
  SILDebugScope(SILLocation Loc)
      : Loc(Loc), InlinedCallSite(nullptr) {}

  /// Create an inlined version of CalleeScope.
  SILDebugScope(const SILDebugScope *CallSiteScope,
                const SILDebugScope *CalleeScope)
    : Loc(CalleeScope->Loc), Parent(CalleeScope),
        InlinedCallSite(CallSiteScope) {
    assert(CallSiteScope && CalleeScope);
    if (InlinedCallSite)
      assert(!InlinedCallSite->InlinedCallSite &&
             "a call site scope cannot have an inlined call site");
  }

  /// Return the function this scope originated from before being inlined.
  SILFunction *getInlinedFunction() const {
    if (Parent.isNull())
      return nullptr;

    const SILDebugScope *Scope = this;
    while (Scope->Parent.is<const SILDebugScope *>())
      Scope = Scope->Parent.get<const SILDebugScope *>();
    assert(Scope->Parent.is<SILFunction *>() && "orphaned scope");
    return Scope->Parent.get<SILFunction *>();
  }

  /// Return this scope without inline information.
  const SILDebugScope *getInlinedScope() const {
    return InlinedCallSite ? Parent.get<const SILDebugScope*>() : this;
  }
  
  /// Return the parent function of this scope. If the scope was
  /// inlined this recursively returns the function it was inlined
  /// into.
  SILFunction *getParentFunction() const {
    if (InlinedCallSite)
      return InlinedCallSite->Parent.get<const SILDebugScope *>()
          ->getParentFunction();
    if (auto *ParentScope = Parent.dyn_cast<const SILDebugScope *>())
      return ParentScope->getParentFunction();
    return Parent.get<SILFunction *>();
  }

  typedef SmallVector<const SILDebugScope *, 8> InlineScopeList;
  static void flatten(const SILDebugScope *DS, InlineScopeList &List);

  // Return a flattened representation of the inline scope tree that
  // is equivalent to the reversed inlined-at chain.
  InlineScopeList flattenedInlineTree() const {
    InlineScopeList List;
    flatten(this, List);
    return List;
  }

  void dump(SourceManager &SM, llvm::raw_ostream &OS = llvm::errs(),
            unsigned Indent = 0) const;
};

#ifndef NDEBUG
/// Determine whether an instruction may not have a SILDebugScope.
bool maybeScopeless(SILInstruction &I);
#endif

/// Knows how to make a deep copy of a debug scope.
class ScopeCloner {
  llvm::SmallDenseMap<const SILDebugScope *,
                      const SILDebugScope *> ClonedScopeCache;
  SILFunction &NewFn;
public:
  /// ScopeCloner expects NewFn to be a clone of the original
  /// function, with all debug scopes and locations still pointing to
  /// the original function.
  ScopeCloner(SILFunction &NewFn);
  /// Return a (cached) deep copy of a scope.
  const SILDebugScope *getOrCreateClonedScope(const SILDebugScope *OrigScope);
};

}

#endif