6 #include <elfutils/libdw.h>
8 #include "mc_private.h"
10 static int mc_dwarf_push_value(mc_expression_state_t state, Dwarf_Off value) {
11 if(state->stack_size>=MC_EXPRESSION_STACK_SIZE)
12 return MC_EXPRESSION_E_STACK_OVERFLOW;
14 state->stack[state->stack_size++] = value;
18 int mc_dwarf_execute_expression(
19 size_t n, const Dwarf_Op* ops, mc_expression_state_t state) {
20 for(int i=0; i!=n; ++i) {
22 const Dwarf_Op* op = ops + i;
23 uint8_t atom = op->atom;
29 case DW_OP_breg0: case DW_OP_breg1: case DW_OP_breg2: case DW_OP_breg3:
30 case DW_OP_breg4: case DW_OP_breg5: case DW_OP_breg6: case DW_OP_breg7:
31 case DW_OP_breg8: case DW_OP_breg9: case DW_OP_breg10: case DW_OP_breg11:
32 case DW_OP_breg12: case DW_OP_breg13: case DW_OP_breg14: case DW_OP_breg15:
33 case DW_OP_breg16: case DW_OP_breg17: case DW_OP_breg18: case DW_OP_breg19:
34 case DW_OP_breg20: case DW_OP_breg21: case DW_OP_breg22: case DW_OP_breg23:
35 case DW_OP_breg24: case DW_OP_breg25: case DW_OP_breg26: case DW_OP_breg27:
36 case DW_OP_breg28: case DW_OP_breg29: case DW_OP_breg30: case DW_OP_breg31:{
37 int register_id = op->atom - DW_OP_breg0;
40 return MC_EXPRESSION_E_MISSING_STACK_CONTEXT;
41 unw_get_reg(state->cursor, register_id, &res);
42 error = mc_dwarf_push_value(state, res + op->number);
46 // Push the CFA (Canonical Frame Addresse):
47 case DW_OP_call_frame_cfa:
49 // UNW_X86_64_CFA does not return the CFA DWARF expects
50 // (it is a synonym for UNW_X86_64_RSP) so copy the cursor,
51 // unwind it once in order to find the parent SP:
54 return MC_EXPRESSION_E_MISSING_STACK_CONTEXT;
57 unw_cursor_t cursor = *(state->cursor);
61 unw_get_reg(&cursor, UNW_TDEP_SP, &res);
62 error = mc_dwarf_push_value(state, res);
70 if(!state->frame_base)
71 return MC_EXPRESSION_E_MISSING_FRAME_BASE;
72 error = mc_dwarf_push_value(state, ((uintptr_t)state->frame_base) + op->number);
79 case DW_OP_lit0: case DW_OP_lit1: case DW_OP_lit2: case DW_OP_lit3:
80 case DW_OP_lit4: case DW_OP_lit5: case DW_OP_lit6: case DW_OP_lit7:
81 case DW_OP_lit8: case DW_OP_lit9: case DW_OP_lit10: case DW_OP_lit11:
82 case DW_OP_lit12: case DW_OP_lit13: case DW_OP_lit14: case DW_OP_lit15:
83 case DW_OP_lit16: case DW_OP_lit17: case DW_OP_lit18: case DW_OP_lit19:
84 case DW_OP_lit20: case DW_OP_lit21: case DW_OP_lit22: case DW_OP_lit23:
85 case DW_OP_lit24: case DW_OP_lit25: case DW_OP_lit26: case DW_OP_lit27:
86 case DW_OP_lit28: case DW_OP_lit29: case DW_OP_lit30: case DW_OP_lit31:
87 error = mc_dwarf_push_value(state, atom - DW_OP_lit0);
91 if(!state->object_info)
92 return MC_EXPRESSION_E_NO_BASE_ADDRESS;
93 if(state->stack_size==MC_EXPRESSION_STACK_SIZE)
94 return MC_EXPRESSION_E_STACK_OVERFLOW;
95 error = mc_dwarf_push_value(state, (Dwarf_Off)MC_object_base_address(state->object_info) + op->number);
108 if(state->stack_size==MC_EXPRESSION_STACK_SIZE)
109 return MC_EXPRESSION_E_STACK_OVERFLOW;
110 error = mc_dwarf_push_value(state, op->number);
113 // Stack manipulation:
115 // Push the value at the top of the stack:
117 if(state->stack_size==0)
118 return MC_EXPRESSION_E_STACK_UNDERFLOW;
120 error = mc_dwarf_push_value(state, state->stack[state->stack_size-1]);
124 if(state->stack_size==0)
125 return MC_EXPRESSION_E_STACK_UNDERFLOW;
131 if(state->stack_size<2)
132 return MC_EXPRESSION_E_STACK_UNDERFLOW;
134 uintptr_t temp = state->stack[state->stack_size-2];
135 state->stack[state->stack_size-2] = state->stack[state->stack_size-1];
136 state->stack[state->stack_size-1] = temp;
141 if(state->stack_size<2)
142 return MC_EXPRESSION_E_STACK_UNDERFLOW;
143 error = mc_dwarf_push_value(state, state->stack[state->stack_size-2]);
149 if(state->stack_size<2)
150 return MC_EXPRESSION_E_STACK_UNDERFLOW;
152 uintptr_t result = state->stack[state->stack_size-2] + state->stack[state->stack_size-1];
153 state->stack[state->stack_size-2] = result;
159 if(state->stack_size<2)
160 return MC_EXPRESSION_E_STACK_UNDERFLOW;
162 uintptr_t result = state->stack[state->stack_size-2] - state->stack[state->stack_size-1];
163 state->stack[state->stack_size-2] = result;
168 case DW_OP_plus_uconst:
169 if(state->stack_size==0)
170 return MC_EXPRESSION_E_STACK_UNDERFLOW;
171 state->stack[state->stack_size-1] += op->number;
175 if(state->stack_size==0)
176 return MC_EXPRESSION_E_STACK_UNDERFLOW;
177 state->stack[state->stack_size-1] = ~state->stack[state->stack_size-1];
181 if(state->stack_size==0)
182 return MC_EXPRESSION_E_STACK_UNDERFLOW;
184 intptr_t value = state->stack[state->stack_size-1];
185 if(value<0) value = -value;
186 state->stack[state->stack_size-1] = value;
191 if(state->stack_size<2)
192 return MC_EXPRESSION_E_STACK_UNDERFLOW;
194 uintptr_t result = state->stack[state->stack_size-2] - state->stack[state->stack_size-1];
195 state->stack[state->stack_size-2] = result;
201 if(state->stack_size<2)
202 return MC_EXPRESSION_E_STACK_UNDERFLOW;
204 uintptr_t result = state->stack[state->stack_size-2] & state->stack[state->stack_size-1];
205 state->stack[state->stack_size-2] = result;
211 if(state->stack_size<2)
212 return MC_EXPRESSION_E_STACK_UNDERFLOW;
214 uintptr_t result = state->stack[state->stack_size-2] | state->stack[state->stack_size-1];
215 state->stack[state->stack_size-2] = result;
221 if(state->stack_size<2)
222 return MC_EXPRESSION_E_STACK_UNDERFLOW;
224 uintptr_t result = state->stack[state->stack_size-2] ^ state->stack[state->stack_size-1];
225 state->stack[state->stack_size-2] = result;
234 case DW_OP_deref_size:
235 return MC_EXPRESSION_E_UNSUPPORTED_OPERATION;
238 if(state->stack_size==0)
239 return MC_EXPRESSION_E_STACK_UNDERFLOW;
242 uintptr_t address = (uintptr_t) state->stack[state->stack_size-1];
243 uintptr_t* p = (uintptr_t*)mc_translate_address(address, state->snapshot);
244 state->stack[state->stack_size-1] = *p;
250 return MC_EXPRESSION_E_UNSUPPORTED_OPERATION;
253 if(error) return error;
260 /** \brief Resolve a location expression
261 * \deprecated Use mc_dwarf_resolve_expression
263 Dwarf_Off mc_dwarf_resolve_location(mc_expression_t expression, mc_object_info_t object_info, unw_cursor_t* c, void* frame_pointer_address, mc_snapshot_t snapshot) {
264 s_mc_expression_state_t state;
265 memset(&state, 0, sizeof(s_mc_expression_state_t));
266 state.frame_base = frame_pointer_address;
268 state.snapshot = snapshot;
269 state.object_info = object_info;
271 if(mc_dwarf_execute_expression(expression->size, expression->ops, &state))
272 xbt_die("Error evaluating DWARF expression");
273 if(state.stack_size==0)
274 xbt_die("No value on the stack");
276 return (Dwarf_Off) state.stack[state.stack_size-1];
279 Dwarf_Off mc_dwarf_resolve_locations(mc_location_list_t locations, mc_object_info_t object_info, unw_cursor_t* c, void* frame_pointer_address, mc_snapshot_t snapshot) {
283 if(unw_get_reg(c, UNW_REG_IP, &ip))
284 xbt_die("Could not resolve IP");
287 for(size_t i=0; i!=locations->size; ++i) {
288 mc_expression_t expression = locations->locations + i;
289 if( (expression->lowpc==NULL && expression->highpc==NULL)
290 || (c && ip >= (unw_word_t) expression->lowpc && ip < (unw_word_t) expression->highpc)) {
291 return mc_dwarf_resolve_location(expression, object_info, c, frame_pointer_address, snapshot);
294 xbt_die("Could not resolve location");
297 /** \brief Find the frame base of a given frame
302 void* mc_find_frame_base(dw_frame_t frame, mc_object_info_t object_info, unw_cursor_t* unw_cursor) {
303 return (void*) mc_dwarf_resolve_locations(&frame->frame_base, object_info, unw_cursor, NULL, NULL);
306 void mc_dwarf_expression_clear(mc_expression_t expression) {
307 free(expression->ops);
308 expression->ops = NULL;
309 expression->size = 0;
310 expression->lowpc = NULL;
311 expression->highpc = NULL;
314 void mc_dwarf_location_list_clear(mc_location_list_t list) {
315 for(size_t i=0; i!=list->size; ++i) {
316 mc_dwarf_expression_clear(list->locations + i);
318 free(list->locations);
319 list->locations = NULL;
323 void mc_dwarf_expression_init(mc_expression_t expression, size_t len, Dwarf_Op* ops) {
324 if(expression->ops) {
325 free(expression->ops);
327 expression->lowpc = NULL;
328 expression->highpc = NULL;
329 expression->size = len;
330 expression->ops = xbt_malloc(len*sizeof(Dwarf_Op));
331 memcpy(expression->ops, ops, len*sizeof(Dwarf_Op));
334 void mc_dwarf_location_list_init_from_expression(mc_location_list_t target, size_t len, Dwarf_Op* ops) {
335 if(target->locations) {
336 mc_dwarf_location_list_clear(target);
339 target->locations = (mc_expression_t) xbt_malloc(sizeof(s_mc_expression_t));
340 mc_dwarf_expression_init(target->locations, len, ops);
343 void mc_dwarf_location_list_init(mc_location_list_t list, mc_object_info_t info, Dwarf_Die* die, Dwarf_Attribute* attr) {
344 if(list->locations) {
345 mc_dwarf_location_list_clear(list);
349 ptrdiff_t offset = 0;
350 Dwarf_Addr base, start, end;
356 offset = dwarf_getlocations(attr, offset, &base, &start, &end, &ops, &len);
360 xbt_die("Error while loading location list");
364 list->locations = (mc_expression_t) realloc(list->locations, list->size*sizeof(s_mc_expression_t));
365 mc_expression_t expression = list->locations + i;
367 void* base = info->flags & MC_OBJECT_INFO_EXECUTABLE ? 0 : MC_object_base_address(info);
368 mc_dwarf_expression_init(expression, len, ops);
370 // If start == 0, this is not a location list:
371 expression->lowpc = start == 0 ? NULL : (char*) base + start;
372 expression->highpc = start == 0 ? NULL : (char*) base + end;