+++ /dev/null
-/* Copyright (c) 2015-2019. The SimGrid Team. All rights reserved. */
-
-/* This program is free software; you can redistribute it and/or modify it
- * under the terms of the license (GNU LGPL) which comes with this package. */
-
-#ifndef SIMGRID_MC_DWARF_EXPRESSION_HPP
-#define SIMGRID_MC_DWARF_EXPRESSION_HPP
-
-#include <cstdint>
-#include <cstdlib>
-
-#include <stdexcept> // runtime_error
-#include <utility>
-#include <vector>
-
-#include <elfutils/libdw.h>
-#include <libunwind.h>
-
-#include "src/mc/AddressSpace.hpp"
-#include "src/mc/mc_dwarf.hpp"
-#include "src/mc/mc_forward.hpp"
-
-/** @file DwarfExpression.hpp
- *
- * Evaluation of DWARF location expressions.
- */
-
-namespace simgrid {
-namespace dwarf {
-
-/** A DWARF expression
- *
- * DWARF defines a simple stack-based VM for evaluating expressions
- * (such as locations of variables, etc.): a DWARF expression is
- * just a sequence of dwarf instructions. We currently directly use
- * `Dwarf_Op` from `dwarf.h` for dwarf instructions.
- */
-typedef std::vector<Dwarf_Op> DwarfExpression;
-
-/** Context of evaluation of a DWARF expression
- *
- * Some DWARF instructions need to read the CPU registers,
- * the process memory, etc. All those informations are gathered in
- * the evaluation context.
- */
-class ExpressionContext {
-public:
- ExpressionContext() :
- cursor(nullptr), frame_base(nullptr), address_space(nullptr),
- object_info(nullptr), process_index(simgrid::mc::ProcessIndexMissing) {}
- /** CPU state (registers) */
- unw_cursor_t* cursor;
- void* frame_base;
- /** Address space used to read memory */
- simgrid::mc::AddressSpace* address_space;
- simgrid::mc::ObjectInformation* object_info;
- int process_index;
-};
-
-/** When an error happens in the execution of a DWARF expression */
-class evaluation_error : public std::runtime_error {
-public:
- explicit evaluation_error(const char* what) : std::runtime_error(what) {}
-};
-
-/** A stack for evaluating a DWARF expression
- *
- * DWARF expressions work by manipulating a stack of integer values.
- */
-class ExpressionStack {
-public:
- typedef std::uintptr_t value_type;
- static const std::size_t max_size = 64;
-private:
- // Values of the stack (the top is stack_[size_ - 1]):
- uintptr_t stack_[max_size] {0};
- size_t size_;
-public:
- ExpressionStack() : size_(0) {}
-
- // Access:
- std::size_t size() const { return size_; }
- bool empty() const { return size_ == 0; }
- void clear() { size_ = 0; }
- uintptr_t& operator[](int i) { return stack_[i]; }
- uintptr_t const& operator[](int i) const { return stack_[i]; }
-
- /** Top of the stack */
- value_type& top()
- {
- if (size_ == 0)
- throw evaluation_error("Empty stack");
- return stack_[size_ - 1];
- }
-
- /** Access the i-th element from the top of the stack */
- value_type& top(unsigned i)
- {
- if (size_ < i)
- throw evaluation_error("Invalid element");
- return stack_[size_ - 1 - i];
- }
-
- /** Push a value on the top of the stack */
- void push(value_type value)
- {
- if (size_ == max_size)
- throw evaluation_error("DWARF stack overflow");
- stack_[size_++] = value;
- }
-
- /* Pop a value from the top of the stack */
- value_type pop()
- {
- if (size_ == 0)
- throw evaluation_error("DWARF stack underflow");
- return stack_[--size_];
- }
-
- // These are DWARF operations (DW_OP_foo):
-
- /* Push a copy of the top-value (DW_OP_dup) */
- void dup() { push(top()); }
-
- /* Swap the two top-most values */
- void swap() { std::swap(top(), top(1)); }
-};
-
-/** Executes a DWARF expression
- *
- * @param ops DWARF expression instructions
- * @param n number of instructions
- * @param context evaluation context (registers, memory, etc.)
- * @param stack DWARf stack where the operations are executed
- */
-void execute(const Dwarf_Op* ops, std::size_t n,
- ExpressionContext const& context, ExpressionStack& stack);
-
-/** Executes/evaluates a DWARF expression
- *
- * @param expression DWARF expression to execute
- * @param context evaluation context (registers, memory, etc.)
- * @param stack DWARf stack where the operations are executed
- */
-inline
-void execute(simgrid::dwarf::DwarfExpression const& expression,
- ExpressionContext const& context, ExpressionStack& stack)
-{
- execute(expression.data(), expression.size(), context, stack);
-}
-
-}
-}
-
-#endif
