/** Pointer to a remote address-space (process, snapshot)
*
* With this we can clearly identify the expected type of an address in the
- * remote process whild avoiding to use native local pointers.
+ * remote process while avoiding to use native local pointers.
+ *
+ * Some operators (+/-) assume use the size of the underlying element. This
+ * only works if the target applications is using the same target: it won't
+ * work for example, when inspecting a 32 bit application from a 64 bit
+ * model-checker.
*/
template<class T> class remote_ptr {
std::uint64_t address_;
remote_ptr(std::uint64_t address) : address_(address) {}
remote_ptr(T* address) : address_((std::uintptr_t)address) {}
std::uint64_t address() const { return address_; }
+
operator bool() const
{
return address_;
*/
const int ProcessIndexAny = 0;
+/** Options for read operations
+ *
+ * This is a set of flags managed with bitwise operators. Only the
+ * meaningful operations are defined: addition, conversions to/from
+ * integers are not allowed.
+ */
+class ReadOptions {
+ std::uint32_t value_;
+ constexpr explicit ReadOptions(std::uint32_t value) : value_(value) {}
+public:
+ constexpr ReadOptions() : value_(0) {}
+
+ constexpr operator bool() const { return value_ != 0; }
+ constexpr bool operator!() const { return value_ == 0; }
+
+ constexpr ReadOptions operator|(ReadOptions const& that) const
+ {
+ return ReadOptions(value_ | that.value_);
+ }
+ constexpr ReadOptions operator&(ReadOptions const& that) const
+ {
+ return ReadOptions(value_ & that.value_);
+ }
+ constexpr ReadOptions operator^(ReadOptions const& that) const
+ {
+ return ReadOptions(value_ ^ that.value_);
+ }
+ constexpr ReadOptions operator~() const
+ {
+ return ReadOptions(~value_);
+ }
+
+ ReadOptions& operator|=(ReadOptions const& that)
+ {
+ value_ |= that.value_;
+ return *this;
+ }
+ ReadOptions& operator&=(ReadOptions const& that)
+ {
+ value_ &= that.value_;
+ return *this;
+ }
+ ReadOptions& operator^=(ReadOptions const& that)
+ {
+ value_ &= that.value_;
+ return *this;
+ }
+
+ /** Copy the data to the given buffer */
+ static constexpr ReadOptions none() { return ReadOptions(0); }
+
+ /** Allows to return a pointer to another buffer where the data is
+ * available instead of copying the data into the buffer
+ */
+ static constexpr ReadOptions lazy() { return ReadOptions(1); }
+};
+
+/** A given state of a given process (abstract base class)
+ *
+ * Currently, this might either be:
+ *
+ * * the current state of an existing process;
+ *
+ * * a snapshot.
+ */
class AddressSpace {
private:
Process* process_;
public:
- enum ReadMode {
- Normal,
- /** Allows the `read_bytes` to return a pointer to another buffer
- * where the data ins available instead of copying the data into the buffer
- */
- Lazy
- };
AddressSpace(Process* process) : process_(process) {}
virtual ~AddressSpace();
simgrid::mc::Process* process() const { return process_; }
+
+ /** Read data from the address space
+ *
+ * @param buffer target buffer for the data
+ * @param size number of bytes
+ * @param address remote source address of the data
+ * @param process_index which process (used for SMPI privatization)
+ * @param options
+ */
virtual const void* read_bytes(void* buffer, std::size_t size,
remote_ptr<void> address, int process_index = ProcessIndexAny,
- ReadMode mode = Normal) const = 0;
+ ReadOptions options = ReadOptions::none()) const = 0;
+ /** Read a given data structure from the address space */
template<class T> inline
void read(T *buffer, remote_ptr<T> ptr, int process_index = ProcessIndexAny)
{
this->read_bytes(buffer, sizeof(T), ptr, process_index);
}
+ /** Read a given data structure from the address space */
template<class T> inline
T read(remote_ptr<T> ptr, int process_index = ProcessIndexMissing)
{
case DW_OP_breg29:
case DW_OP_breg30:
case DW_OP_breg31:{
+ // Push register + constant:
int register_id = simgrid::dwarf::dwarf_register_to_libunwind(
op->atom - DW_OP_breg0);
unw_word_t res;
if (!context.cursor)
- throw evaluation_error("Missin stack context");
+ throw evaluation_error("Missing stack context");
unw_get_reg(context.cursor, register_id, &res);
stack.push(res + op->number);
break;
// ***** Constants:
// Short constant literals:
- // DW_OP_lit15 pushed the 15 on the stack.
case DW_OP_lit0:
case DW_OP_lit1:
case DW_OP_lit2:
case DW_OP_lit29:
case DW_OP_lit30:
case DW_OP_lit31:
+ // Push a literal/constant on the stack:
stack.push(atom - DW_OP_lit0);
break;
stack.pop();
break;
- // Swap the two top-most value of the stack:
case DW_OP_swap:
- std::swap(stack.top(), stack.top(1));
+ stack.swap();
break;
// Duplicate the value under the top of the stack:
#define SIMGRID_MC_DWARF_EXPRESSION_HPP
#include <cstdint>
-
+#include <cstdlib>
#include <stdexcept>
#include "src/mc/AddressSpace.hpp"
+/** @file DwarfExession.hpp
+ *
+ * Evaluation of DWARF location expressions
+ */
+
namespace simgrid {
namespace dwarf {
-class evaluation_error : std::runtime_error {
-public:
- evaluation_error(const char* what): std::runtime_error(what) {}
- ~evaluation_error() noexcept(true);
-};
+/** A DWARF expression
+ *
+ * DWARF defines a simple stack-based VM for evaluating expressions
+ * (such as locations of variables, etc.): A DWARF expressions 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.
+ */
struct ExpressionContext {
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;
};
-typedef std::vector<Dwarf_Op> DwarfExpression;
+/** When an error happens in the execution of a DWARF expression */
+class evaluation_error : std::runtime_error {
+public:
+ evaluation_error(const char* what): std::runtime_error(what) {}
+ ~evaluation_error() noexcept(true);
+};
+/** 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;
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)
return stack_[size_ - 1 - i];
}
- // Push/pop:
+ /** 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)
return stack_[--size_];
}
- // Other operations:
+ // 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)
const void *Process::read_bytes(void* buffer, std::size_t size,
remote_ptr<void> address, int process_index,
- AddressSpace::ReadMode mode) const
+ ReadOptions options) const
{
if (process_index != simgrid::mc::ProcessIndexDisabled) {
std::shared_ptr<simgrid::mc::ObjectInformation> const& info =
// Read memory:
const void* read_bytes(void* buffer, std::size_t size,
remote_ptr<void> address, int process_index = ProcessIndexAny,
- ReadMode mode = Normal) const override;
+ ReadOptions options = ReadOptions::none()) const override;
void read_variable(const char* name, void* target, size_t size) const;
template<class T>
T read_variable(const char *name) const
xbt_mheap_t heap1 = (xbt_mheap_t)s1->read_bytes(
alloca(sizeof(struct mdesc)), sizeof(struct mdesc),
remote(process->heap_address),
- simgrid::mc::ProcessIndexMissing, simgrid::mc::AddressSpace::Lazy);
+ simgrid::mc::ProcessIndexMissing, simgrid::mc::ReadOptions::lazy());
xbt_mheap_t heap2 = (xbt_mheap_t)s2->read_bytes(
alloca(sizeof(struct mdesc)), sizeof(struct mdesc),
remote(process->heap_address),
- simgrid::mc::ProcessIndexMissing, simgrid::mc::AddressSpace::Lazy);
+ simgrid::mc::ProcessIndexMissing, simgrid::mc::ReadOptions::lazy());
res_init = init_heap_information(heap1, heap2, &s1->to_ignore, &s2->to_ignore);
if (res_init == -1) {
#ifdef MC_DEBUG
/* Compare global variables */
is_diff =
- compare_global_variables(region1->object_info( ), simgrid::mc::AddressSpace::Normal,
+ compare_global_variables(region1->object_info(),
+ simgrid::mc::ProcessIndexDisabled,
region1, region2,
s1, s2);
const void* Snapshot::read_bytes(void* buffer, std::size_t size,
remote_ptr<void> address, int process_index,
- AddressSpace::ReadMode mode) const
+ ReadOptions options) const
{
mc_mem_region_t region = mc_get_snapshot_region((void*)address.address(), this, process_index);
if (region) {
const void* res = MC_region_read(region, buffer, (void*)address.address(), size);
- if (buffer == res || mode == AddressSpace::Lazy)
+ if (buffer == res || options & ReadOptions::lazy())
return res;
else {
memcpy(buffer, res, size);
}
else
return this->process()->read_bytes(
- buffer, size, address, process_index, mode);
+ buffer, size, address, process_index, options);
}
}
~Snapshot();
const void* read_bytes(void* buffer, std::size_t size,
remote_ptr<void> address, int process_index = ProcessIndexAny,
- ReadMode mode = Normal) const override;
+ ReadOptions options = ReadOptions::none()) const override;
public: // To be private
int num_state;
std::size_t heap_bytes_used;
char *route_name = bprintf("%s#%s", src->name(), dst->name());
if (bypassRoutes_->find(route_name) != bypassRoutes_->end()) {
bypassedRoute = bypassRoutes_->at(route_name);
- XBT_DEBUG("Found a bypass route with %ld links",bypassedRoute->size());
+ XBT_DEBUG("Found a bypass route with %zu links",bypassedRoute->size());
}
free(route_name);
return bypassedRoute;
