lldb/Expression/ClangExpressionVariable.h

//===-- ClangExpressionVariable.h -------------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#ifndef liblldb_ClangExpressionVariable_h_
#define liblldb_ClangExpressionVariable_h_

// C Includes
#include <signal.h>
#include <stdint.h>
#include <string.h>

// C++ Includes
#include <map>
#include <string>
#include <vector>

// Other libraries and framework includes
// Project includes
#include "lldb/lldb-public.h"
#include "lldb/Core/ClangForward.h"
#include "lldb/Core/ConstString.h"
#include "lldb/Core/Value.h"
#include "lldb/Symbol/TaggedASTType.h"

namespace llvm {
    class Value;
}

namespace lldb_private {

class ClangExpressionVariableList;
class ValueObjectConstResult;

//----------------------------------------------------------------------
/// @class ClangExpressionVariable ClangExpressionVariable.h "lldb/Expression/ClangExpressionVariable.h"
/// @brief Encapsulates one variable for the expression parser.
///
/// The expression parser uses variables in three different contexts:
///
/// First, it stores persistent variables along with the process for use
/// in expressions.  These persistent variables contain their own data
/// and are typed.
///
/// Second, in an interpreted expression, it stores the local variables
/// for the expression along with the expression.  These variables
/// contain their own data and are typed.
///
/// Third, in a JIT-compiled expression, it stores the variables that
/// the expression needs to have materialized and dematerialized at each
/// execution.  These do not contain their own data but are named and
/// typed.
///
/// This class supports all of these use cases using simple type
/// polymorphism, and provides necessary support methods.  Its interface
/// is RTTI-neutral.
//----------------------------------------------------------------------
class ClangExpressionVariable
{
public:
    ClangExpressionVariable(ExecutionContextScope *exe_scope, lldb::ByteOrder byte_order, uint32_t addr_byte_size);

    ClangExpressionVariable(const lldb::ValueObjectSP &valobj_sp);

    //----------------------------------------------------------------------
    /// If the variable contains its own data, make a Value point at it.
    /// If \a exe_ctx in not NULL, the value will be resolved in with
    /// that execution context.
    ///
    /// @param[in] value
    ///     The value to point at the data.
    ///
    /// @param[in] exe_ctx
    ///     The execution context to use to resolve \a value.
    ///
    /// @return
    ///     True on success; false otherwise (in particular, if this variable
    ///     does not contain its own data).
    //----------------------------------------------------------------------
    bool
    PointValueAtData(Value &value, ExecutionContext *exe_ctx);

    lldb::ValueObjectSP
    GetValueObject();

    //----------------------------------------------------------------------
    /// The following values should not live beyond parsing
    //----------------------------------------------------------------------
    class ParserVars
    {
    public:

        ParserVars() :
            m_parser_type(),
            m_named_decl (NULL),
            m_llvm_value (NULL),
            m_lldb_value (),
            m_lldb_var   (),
            m_lldb_sym   (NULL)
        {
        }

        TypeFromParser          m_parser_type;  ///< The type of the variable according to the parser
        const clang::NamedDecl *m_named_decl;   ///< The Decl corresponding to this variable
        llvm::Value            *m_llvm_value;   ///< The IR value corresponding to this variable; usually a GlobalValue
        lldb_private::Value     m_lldb_value;   ///< The value found in LLDB for this variable
        lldb::VariableSP        m_lldb_var;     ///< The original variable for this variable
        const lldb_private::Symbol *m_lldb_sym; ///< The original symbol for this variable, if it was a symbol
    };

private:
    typedef std::map <uint64_t, ParserVars> ParserVarMap;
    ParserVarMap m_parser_vars;

public:
    //----------------------------------------------------------------------
    /// Make this variable usable by the parser by allocating space for
    /// parser-specific variables
    //----------------------------------------------------------------------
    void
    EnableParserVars(uint64_t parser_id)
    {
        m_parser_vars.insert(std::make_pair(parser_id, ParserVars()));
    }

    //----------------------------------------------------------------------
    /// Deallocate parser-specific variables
    //----------------------------------------------------------------------
    void
    DisableParserVars(uint64_t parser_id)
    {
        m_parser_vars.erase(parser_id);
    }

    //----------------------------------------------------------------------
    /// Access parser-specific variables
    //----------------------------------------------------------------------
    ParserVars *
    GetParserVars(uint64_t parser_id)
    {
        ParserVarMap::iterator i = m_parser_vars.find(parser_id);

        if (i == m_parser_vars.end())
            return NULL;
        else
            return &i->second;
    }

    //----------------------------------------------------------------------
    /// The following values are valid if the variable is used by JIT code
    //----------------------------------------------------------------------
    struct JITVars {
        JITVars () :
            m_alignment (0),
            m_size (0),
            m_offset (0)
        {
        }

        off_t   m_alignment;    ///< The required alignment of the variable, in bytes
        size_t  m_size;         ///< The space required for the variable, in bytes
        off_t   m_offset;       ///< The offset of the variable in the struct, in bytes
    };

private:
    typedef std::map <uint64_t, JITVars> JITVarMap;
    JITVarMap m_jit_vars;

public:
    //----------------------------------------------------------------------
    /// Make this variable usable for materializing for the JIT by allocating
    /// space for JIT-specific variables
    //----------------------------------------------------------------------
    void
    EnableJITVars(uint64_t parser_id)
    {
        m_jit_vars.insert(std::make_pair(parser_id, JITVars()));
    }

    //----------------------------------------------------------------------
    /// Deallocate JIT-specific variables
    //----------------------------------------------------------------------
    void
    DisableJITVars(uint64_t parser_id)
    {
        m_jit_vars.erase(parser_id);
    }

    JITVars *GetJITVars(uint64_t parser_id)
    {
        JITVarMap::iterator i = m_jit_vars.find(parser_id);

        if (i == m_jit_vars.end())
            return NULL;
        else
            return &i->second;
    }

    //----------------------------------------------------------------------
    /// Return the variable's size in bytes
    //----------------------------------------------------------------------
    size_t
    GetByteSize ();

    const ConstString &
    GetName();

    RegisterInfo *
    GetRegisterInfo();

    void
    SetRegisterInfo (const RegisterInfo *reg_info);

    ClangASTType
    GetClangType ();

    void
    SetClangType (const ClangASTType &clang_type);

    TypeFromUser
    GetTypeFromUser ();

    uint8_t *
    GetValueBytes ();

    void
    SetName (const ConstString &name);

    void
    ValueUpdated ();

    // this function is used to copy the address-of m_live_sp into m_frozen_sp
    // this is necessary because the results of certain cast and pointer-arithmetic
    // operations (such as those described in bugzilla issues 11588 and 11618) generate
    // frozen objcts that do not have a valid address-of, which can be troublesome when
    // using synthetic children providers. transferring the address-of the live object
    // solves these issues and provides the expected user-level behavior
    void
    TransferAddress (bool force = false);

    typedef std::shared_ptr<ValueObjectConstResult> ValueObjectConstResultSP;

    //----------------------------------------------------------------------
    /// Members
    //----------------------------------------------------------------------
    enum Flags
    {
        EVNone                  = 0,
        EVIsLLDBAllocated       = 1 << 0,   ///< This variable is resident in a location specifically allocated for it by LLDB in the target process
        EVIsProgramReference    = 1 << 1,   ///< This variable is a reference to a (possibly invalid) area managed by the target program
        EVNeedsAllocation       = 1 << 2,   ///< Space for this variable has yet to be allocated in the target process
        EVIsFreezeDried         = 1 << 3,   ///< This variable's authoritative version is in m_frozen_sp (for example, for statically-computed results)
        EVNeedsFreezeDry        = 1 << 4,   ///< Copy from m_live_sp to m_frozen_sp during dematerialization
        EVKeepInTarget          = 1 << 5,   ///< Keep the allocation after the expression is complete rather than freeze drying its contents and freeing it
        EVTypeIsReference       = 1 << 6,   ///< The original type of this variable is a reference, so materialize the value rather than the location
        EVUnknownType           = 1 << 7,   ///< This is a symbol of unknown type, and the type must be resolved after parsing is complete
        EVBareRegister          = 1 << 8    ///< This variable is a direct reference to $pc or some other entity.
    };

    typedef uint16_t FlagType;

    FlagType m_flags; // takes elements of Flags

    lldb::ValueObjectSP m_frozen_sp;
    lldb::ValueObjectSP m_live_sp;

    DISALLOW_COPY_AND_ASSIGN (ClangExpressionVariable);
};

//----------------------------------------------------------------------
/// @class ClangExpressionVariableListBase ClangExpressionVariable.h "lldb/Expression/ClangExpressionVariable.h"
/// @brief A list of variable references.
///
/// This class stores variables internally, acting as the permanent store.
//----------------------------------------------------------------------
class ClangExpressionVariableList
{
public:
    //----------------------------------------------------------------------
    /// Implementation of methods in ClangExpressionVariableListBase
    //----------------------------------------------------------------------
    size_t
    GetSize()
    {
        return m_variables.size();
    }

    lldb::ClangExpressionVariableSP
    GetVariableAtIndex(size_t index)
    {
        lldb::ClangExpressionVariableSP var_sp;
        if (index < m_variables.size())
            var_sp = m_variables[index];
        return var_sp;
    }

    size_t
    AddVariable (const lldb::ClangExpressionVariableSP &var_sp)
    {
        m_variables.push_back(var_sp);
        return m_variables.size() - 1;
    }

    bool
    ContainsVariable (const lldb::ClangExpressionVariableSP &var_sp)
    {
        const size_t size = m_variables.size();
        for (size_t index = 0; index < size; ++index)
        {
            if (m_variables[index].get() == var_sp.get())
                return true;
        }
        return false;
    }

    //----------------------------------------------------------------------
    /// Finds a variable by name in the list.
    ///
    /// @param[in] name
    ///     The name of the requested variable.
    ///
    /// @return
    ///     The variable requested, or NULL if that variable is not in the list.
    //----------------------------------------------------------------------
    lldb::ClangExpressionVariableSP
    GetVariable (const ConstString &name)
    {
        lldb::ClangExpressionVariableSP var_sp;
        for (size_t index = 0, size = GetSize(); index < size; ++index)
        {
            var_sp = GetVariableAtIndex(index);
            if (var_sp->GetName() == name)
                return var_sp;
        }
        var_sp.reset();
        return var_sp;
    }

    lldb::ClangExpressionVariableSP
    GetVariable (const char *name)
    {
        lldb::ClangExpressionVariableSP var_sp;
        if (name && name[0])
        {
            for (size_t index = 0, size = GetSize(); index < size; ++index)
            {
                var_sp = GetVariableAtIndex(index);
                const char *var_name_cstr = var_sp->GetName().GetCString();
                if (!var_name_cstr || !name)
                    continue;
                if (::strcmp (var_name_cstr, name) == 0)
                    return var_sp;
            }
            var_sp.reset();
        }
        return var_sp;
    }

    //----------------------------------------------------------------------
    /// Finds a variable by NamedDecl in the list.
    ///
    /// @param[in] name
    ///     The name of the requested variable.
    ///
    /// @return
    ///     The variable requested, or NULL if that variable is not in the list.
    //----------------------------------------------------------------------
    lldb::ClangExpressionVariableSP
    GetVariable (const clang::NamedDecl *decl, uint64_t parser_id)
    {
        lldb::ClangExpressionVariableSP var_sp;
        for (size_t index = 0, size = GetSize(); index < size; ++index)
        {
            var_sp = GetVariableAtIndex(index);

            ClangExpressionVariable::ParserVars *parser_vars = var_sp->GetParserVars(parser_id);

            if (parser_vars && parser_vars->m_named_decl == decl)
                return var_sp;
        }
        var_sp.reset();
        return var_sp;
    }

    //----------------------------------------------------------------------
    /// Create a new variable in the list and return its index
    //----------------------------------------------------------------------
    lldb::ClangExpressionVariableSP
    CreateVariable (ExecutionContextScope *exe_scope, lldb::ByteOrder byte_order, uint32_t addr_byte_size)
    {
        lldb::ClangExpressionVariableSP var_sp(new ClangExpressionVariable(exe_scope, byte_order, addr_byte_size));
        m_variables.push_back(var_sp);
        return var_sp;
    }

    lldb::ClangExpressionVariableSP
    CreateVariable(const lldb::ValueObjectSP &valobj_sp)
    {
        lldb::ClangExpressionVariableSP var_sp(new ClangExpressionVariable(valobj_sp));
        m_variables.push_back(var_sp);
        return var_sp;
    }

    lldb::ClangExpressionVariableSP
    CreateVariable (ExecutionContextScope *exe_scope,
                    const ConstString &name,
                    const TypeFromUser& user_type,
                    lldb::ByteOrder byte_order,
                    uint32_t addr_byte_size)
    {
        lldb::ClangExpressionVariableSP var_sp(new ClangExpressionVariable(exe_scope, byte_order, addr_byte_size));
        var_sp->SetName (name);
        var_sp->SetClangType (user_type);
        m_variables.push_back(var_sp);
        return var_sp;
    }

    void
    RemoveVariable (lldb::ClangExpressionVariableSP var_sp)
    {
        for (std::vector<lldb::ClangExpressionVariableSP>::iterator vi = m_variables.begin(), ve = m_variables.end();
             vi != ve;
             ++vi)
        {
            if (vi->get() == var_sp.get())
            {
                m_variables.erase(vi);
                return;
            }
        }
    }

    void
    Clear()
    {
        m_variables.clear();
    }

private:
    std::vector <lldb::ClangExpressionVariableSP> m_variables;
};


} // namespace lldb_private

#endif  // liblldb_ClangExpressionVariable_h_