/*===================== begin_copyright_notice ==================================

Copyright (c) 2017 Intel Corporation

Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be included
in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.


======================= end_copyright_notice ==================================*/

//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//

///////////////////////////////////////////////////////////////////////////////
// This file is based on llvm-3.4\include\llvm\CodeGen\LexicalScopes.h
///////////////////////////////////////////////////////////////////////////////

#pragma once

#include "llvm/Config/llvm-config.h"

#include "common/LLVMWarningsPush.hpp"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/IR/DebugLoc.h"
#include "llvm/IR/ValueHandle.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/IR/DebugInfoMetadata.h"
#include "common/LLVMWarningsPop.hpp"

#include <utility>
#include <unordered_map>

namespace IGC
{
class VISAModule;

//===----------------------------------------------------------------------===//
/// InsnRange - This is used to track range of instructions with identical
/// lexical scope.
///
typedef std::pair<const llvm::Instruction *, const llvm::Instruction *> InsnRange;

//===----------------------------------------------------------------------===//
/// LexicalScope - This class is used to track scope information.
///
class LexicalScope
{
public:
    LexicalScope(LexicalScope *P, const llvm::DILocalScope *D, const llvm::DILocation *I,
        bool A)
        : Parent(P), Desc(D), InlinedAtLocation(I), AbstractScope(A),
        LastInsn(nullptr), FirstInsn(nullptr), DFSIn(0), DFSOut(0) {
        assert((!D || D->isResolved()) && "Expected resolved node");
        assert((!I || I->isResolved()) && "Expected resolved node");
        if (Parent)
            Parent->addChild(this);
    }

    virtual ~LexicalScope() {}

    // Accessors.
    LexicalScope *getParent() const                      { return Parent; }
    const llvm::MDNode *getDesc() const                  { return Desc; }
    const llvm::MDNode *getInlinedAt() const             { return InlinedAtLocation; }
    const llvm::MDNode *getScopeNode() const             { return Desc; }
    bool isAbstractScope() const                         { return AbstractScope; }
    llvm::SmallVectorImpl<LexicalScope *> &getChildren() { return Children; }
    llvm::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 llvm::Instruction *MI)
    {
        if (!FirstInsn)
            FirstInsn = MI;

        if (Parent)
            Parent->openInsnRange(MI);
    }

    /// extendInsnRange - Extend the current instruction range covered by
    /// this scope.
    void extendInsnRange(const llvm::Instruction *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 = NULL)
    {
        assert(LastInsn && "Last insn missing!");
        Ranges.push_back(InsnRange(FirstInsn, LastInsn));
        FirstInsn = NULL;
        LastInsn = NULL;
        // 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 llvm::DILocalScope* Desc;                // Debug info descriptor.
    const llvm::DILocation* InlinedAtLocation;   // Location at which this 
    // scope is inlined.
    bool AbstractScope;                            // Abstract Scope
    llvm::SmallVector<LexicalScope *, 4> Children;       // Scopes defined in scope.  
    // Contents not owned.
    llvm::SmallVector<InsnRange, 4> Ranges;

    const llvm::Instruction *LastInsn;       // Last instruction of this scope.
    const llvm::Instruction *FirstInsn;      // First instruction of this scope.
    unsigned DFSIn, DFSOut;             // In & Out Depth use to determine
    // scope nesting.
};

//===----------------------------------------------------------------------===//
/// LexicalScopes -  This class provides interface to collect and use lexical
/// scoping information from machine instruction.
///
class LexicalScopes
{
public:
    LexicalScopes() : VisaM(NULL), CurrentFnLexicalScope(NULL) { }
    virtual ~LexicalScopes();

    /// initialize - Scan machine function and constuct lexical scope nest.
    virtual void initialize(const VISAModule *M);

    /// releaseMemory - release memory.
    virtual void releaseMemory();

    /// empty - Return true if there is any lexical scope information available.
    bool empty() { return CurrentFnLexicalScope == NULL; }

    /// isCurrentFunctionScope - Return true if given lexical scope represents 
    /// current function.
    bool isCurrentFunctionScope(const LexicalScope *LS)
    {
        return LS == CurrentFnLexicalScope;
    }

    /// getCurrentFunctionScope - Return lexical scope for the current function.
    LexicalScope *getCurrentFunctionScope() const { return CurrentFnLexicalScope; }

    /// findLexicalScope - Find lexical scope, either regular or inlined, for the
    /// given DebugLoc. Return NULL if not found.
    LexicalScope *findLexicalScope(const llvm::DILocation* DL);

    /// getAbstractScopesList - Return a reference to list of abstract scopes.
    llvm::ArrayRef<LexicalScope *> getAbstractScopesList() const
    {
        return AbstractScopesList;
    }

    /// findAbstractScope - Find an abstract scope or return NULL.
    LexicalScope *findAbstractScope(const llvm::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 llvm::DILocalScope *N, const llvm::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 llvm::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 llvm::DILocalScope *Scope);

    /// dump - Print data structures to dbgs().
    void dump();

private:
    /// getOrCreateLexicalScope - Find lexical scope for the given Scope/IA. If
    /// not available then create new lexical scope.
    LexicalScope *getOrCreateLexicalScope(const llvm::DILocalScope *Scope,
        const llvm::DILocation *IA = nullptr);
    LexicalScope *getOrCreateLexicalScope(const llvm::DILocation *DL) {
        return DL ? getOrCreateLexicalScope(DL->getScope(), DL->getInlinedAt())
            : nullptr;
    }

    /// getOrCreateRegularScope - Find or create a regular lexical scope.
    LexicalScope *getOrCreateRegularScope(const llvm::DILocalScope *Scope);

    /// getOrCreateInlinedScope - Find or create an inlined lexical scope.
    LexicalScope *getOrCreateInlinedScope(const llvm::DILocalScope *Scope,
        const llvm::DILocation *InlinedAt);

    /// extractLexicalScopes - Extract instruction ranges for each lexical scopes
    /// for the given machine function.
    void extractLexicalScopes(llvm::SmallVectorImpl<InsnRange> &MIRanges,
        llvm::DenseMap<const llvm::Instruction*, LexicalScope *> &M);
    void constructScopeNest(LexicalScope *Scope);
    void
        assignInstructionRanges(llvm::SmallVectorImpl<InsnRange> &MIRanges,
        llvm::DenseMap<const llvm::Instruction*, LexicalScope *> &M);

private:
    const VISAModule *VisaM;

    /// LexicalScopeMap - Tracks the scopes in the current function.
    // Use an unordered_map to ensure value pointer validity over insertion.
    std::unordered_map<const llvm::DILocalScope *, LexicalScope> LexicalScopeMap;

    /// InlinedLexicalScopeMap - Tracks inlined function scopes in current
    /// function.
    std::unordered_map<std::pair<const llvm::DILocalScope *, const llvm::DILocation *>,
        LexicalScope,
        llvm::pair_hash<const llvm::DILocalScope *, const llvm::DILocation * >>
        InlinedLexicalScopeMap;

    /// AbstractScopeMap - These scopes are  not included LexicalScopeMap.
    // Use an unordered_map to ensure value pointer validity over insertion.
    std::unordered_map<const llvm::DILocalScope *, LexicalScope> AbstractScopeMap;

    /// AbstractScopesList - Tracks abstract scopes constructed while processing
    /// a function.
    llvm::SmallVector<LexicalScope *, 4> AbstractScopesList;

    /// CurrentFnLexicalScope - Top level scope for the current function.
    ///
    LexicalScope *CurrentFnLexicalScope;

};

} // namespace IGC
