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use two stage unwinding: 1st is simply detection of function name using

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libunwind and save functions cursor. 2nd - use dwarf information to cath
as more info as possible. this approach also allows to dereference
DW_OP_GNU_value operation since it need access to caller frame from
callee context
This commit is contained in:
nnosov
2020-01-16 14:54:42 +04:00
parent f044133d8a
commit 1cddd773bc
2 changed files with 73 additions and 36 deletions
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framework/sysutils.cpp
+58 -27
View File
@@ -19,9 +19,9 @@
#include "sysutils.h"
#include "logger/log.h"
#define USEI_LIBUNWIND
#define USE_LIBUNWIND
#ifdef USEI_LIBUNWIND
#ifdef USE_LIBUNWIND
#include <libunwind.h>
#endif
@@ -396,9 +396,31 @@ pst_parameter* __pst_function::next_param(pst_parameter* p)
bool __pst_function::print_dwarf()
{
ctx->print("%s:%u: ", file.c_str(), line);
char* at = NULL;
if(!asprintf(&at, " at %s:%d (%p)", file.c_str(), line, (void*)pc)) {
return false;
}
if(at[4] == ':' && at[5] == '-') {
free(at);
if(!asprintf(&at, " at %p", (void*)pc)) {
return false;
}
}
//ctx->print("%s:%d: ", file.c_str(), line);
// handle return parameter and be safe if function haven't parameters (for example, dwar info for function is absent)
pst_parameter* param = next_param(NULL);
if(param && param->is_return) {
// print return value type, function name and start list of parameters
param->print_dwarf();
ctx->print(" %s(", name.c_str());
param = next_param(param);
} else {
ctx->print("%s(", name.c_str());
}
bool first = true; bool start_variable = false;
for(pst_parameter* param = next_param(NULL); param; param = next_param(param)) {
for(; param; param = next_param(param)) {
if(param->is_return) {
// print return value type, function name and start list of parameters
param->print_dwarf();
@@ -408,7 +430,7 @@ bool __pst_function::print_dwarf()
if(param->is_variable) {
if(!start_variable) {
ctx->print(")\n");
ctx->print(")%s\n", at);
ctx->print("{\n");
start_variable = true;
}
@@ -430,17 +452,19 @@ bool __pst_function::print_dwarf()
}
if(!start_variable) {
ctx->print(");\n");
ctx->print(");%s\n", at);
} else {
ctx->print("}\n");
}
free(at);
return true;
}
bool __pst_function::handle_dwarf(Dwarf_Die* d)
{
die = d;
ctx->cursor = cursor;
Dwarf_Attribute attr_mem;
Dwarf_Attribute* attr;
@@ -455,9 +479,9 @@ bool __pst_function::handle_dwarf(Dwarf_Die* d)
// }
unw_proc_info_t info;
unw_get_proc_info(&ctx->cursor, &info);
unw_get_proc_info(&cursor, &info);
unw_word_t sp;
unw_get_reg(&ctx->cursor, UNW_REG_SP, &sp);
unw_get_reg(&cursor, UNW_REG_SP, &sp);
ctx->log(SEVERITY_DEBUG, "Found function in debug info. name = %s(...), PC = 0x%lX, LOW_PC = 0x%lX, HIGH_PC = 0x%lX, offset from base address: 0x%lX, BASE_PC = 0x%lX, offset from start of function: 0x%lX, stack address: 0x%lX",
dwarf_diename(d), pc, lowpc, highpc, pc - ctx->base_addr, info.start_ip, info.start_ip - ctx->base_addr, sp);
@@ -553,7 +577,7 @@ bool __pst_function::handle_dwarf(Dwarf_Die* d)
{
case DW_TAG_GNU_call_site_parameter: {
Dwarf_Addr pc;
unw_get_reg(&ctx->cursor, UNW_REG_IP, &pc);
unw_get_reg(&cursor, UNW_REG_IP, &pc);
dwarf_stack stack(ctx); char str[1024]; uint64_t value;
if(dwarf_hasattr(&child, DW_AT_location)) {
@@ -562,7 +586,9 @@ bool __pst_function::handle_dwarf(Dwarf_Die* d)
attr = dwarf_attr(&child, DW_AT_location, &attr_mem);
if(handle_location(ctx, attr, stack, pc, str, sizeof(str))) {
if(stack.get_value(value)) {
ctx->log(SEVERITY_DEBUG, "%s:%d", __PRETTY_FUNCTION__, __LINE__);
ctx->log(SEVERITY_DEBUG, "Call site Location: %s ==> 0x%lX", str, value);
ctx->log(SEVERITY_DEBUG, "%s:%d", __PRETTY_FUNCTION__, __LINE__);
}
}
}
@@ -726,7 +752,9 @@ bool __pst_handler::get_dwarf_function(pst_function* fun)
int tag = dwarf_tag(&result);
if(tag == DW_TAG_subprogram || tag == DW_TAG_entry_point || tag == DW_TAG_inlined_subroutine) {
if(!strcmp(fun->name.c_str(), dwarf_diename(&result))) {
ctx.log(SEVERITY_DEBUG, "%s:%d", __PRETTY_FUNCTION__, __LINE__);
return fun->handle_dwarf(&result);
ctx.log(SEVERITY_DEBUG, "%s:%d", __PRETTY_FUNCTION__, __LINE__);
}
}
} while(dwarf_siblingof(&result, &result) == 0);
@@ -734,9 +762,9 @@ bool __pst_handler::get_dwarf_function(pst_function* fun)
return nret;
}
pst_function* __pst_handler::add_function()
pst_function* __pst_handler::add_function(__pst_function* fun)
{
pst_function* f = new pst_function(&ctx);
pst_function* f = new pst_function(&ctx, fun);
functions.InsertLast(f);
return f;
@@ -768,6 +796,15 @@ pst_function* __pst_handler::next_function(pst_function* f)
return next;
}
bool __pst_handler::handle_dwarf()
{
for(pst_function* fun = next_function(NULL); fun; fun = next_function(fun)) {
get_dwarf_function(fun);
}
return true;
}
void __pst_handler::print_dwarf()
{
ctx.offset = 0;
@@ -809,6 +846,7 @@ bool __pst_handler::unwind()
#else
# error "unknown architecture!"
#endif
ctx.offset = 0;
handle = dlopen(NULL, RTLD_NOW);
Dl_info info;
@@ -817,12 +855,12 @@ bool __pst_handler::unwind()
ctx.log(SEVERITY_INFO, "Process address information: base address: %p, object name: %s", info.dli_fbase, info.dli_fname);
int skipped = 0;
#ifndef USEI_LIBUNWIND
#ifndef USE_LIBUNWIND
int size = 0;
void * array[50];
size = backtrace(array, 50);
for(int i = 0; i < size && array[i] != caller_address; ++i, ++skipped);
print("Stack trace(caller = %p. Total stack frames: %d, skipped: %d):\n", caller_address, size, skipped);
for(int i = 0; i < size && array[i] != caller; ++i, ++skipped);
ctx.print("Stack trace(caller = %p. Total stack frames: %d, skipped: %d):\n", caller, size, skipped);
#else
unw_word_t pc;
@@ -850,9 +888,10 @@ bool __pst_handler::unwind()
return false;
}
#ifndef USEI_LIBUNWIND
#ifndef USE_LIBUNWIND
for (int i = skipped, idx = 0; i < size ; ++i, ++idx) {
print("[%-2d] ", idx);
uint64_t pc = (uint64_t)array[i];
ctx.print("[%-2d] ", idx);
Dwarf_Addr addr = (uintptr_t)array[i];
#else
for (int i = skipped, idx = 0; true ; ++i, ++idx) {
@@ -862,25 +901,17 @@ bool __pst_handler::unwind()
#endif
module = dwfl_addrmodule(dwfl, addr);
get_frame();
pst_function* fun = add_function();
if(fun->unwind(dwfl, module, pc)) {
if(!get_dwarf_function(fun)) {
del_function(fun);
}
} else {
pst_function* fun = add_function(next_function(NULL)/* first element */);
if(!fun->unwind(dwfl, module, pc)) {
del_function(fun);
}
ctx.print("\n");
#ifdef USEI_LIBUNWIND
#ifdef USE_LIBUNWIND
if(unw_step(&ctx.cursor) <= 0) {
break;
}
#endif
}
// for(int op = DW_OP_breg0; op <= DW_OP_breg16; op++ ) {
// printf("{0x%X, 0x%X, \"%s\"},\n", op, op - DW_OP_breg0, unw_regname(op - DW_OP_breg0));
// }
return true;
}
framework/sysutils.h
+15 -9
View File
@@ -73,7 +73,7 @@ typedef struct __pst_parameter : public SC_ListNode {
void* loc; // pointer to location of parameter's value
bool is_return; // whether this parameter is return value of the function
bool is_variable;// whether this parameter is function variable or argument of function
bool has_value;
bool has_value; // whether we got value of parameter or not
uint64_t value; // value of parameter
pst_context* ctx;
} pst_parameter;
@@ -81,12 +81,15 @@ typedef struct __pst_parameter : public SC_ListNode {
typedef struct __pst_handler pst_handler;
typedef struct __pst_function : public SC_ListNode {
__pst_function(pst_context* ctx) : ctx(ctx) {
__pst_function(pst_context* _ctx, __pst_function* _parent) : ctx(_ctx) {
pc = 0;
line = -1;
die = NULL;
lowpc = 0;
highpc = 0;
parent = NULL;
cursor = _ctx->cursor;
parent = _parent;
}
~__pst_function() {
@@ -102,15 +105,17 @@ typedef struct __pst_function : public SC_ListNode {
bool handle_dwarf(Dwarf_Die* d);
bool print_dwarf();
Dwarf_Addr lowpc;
Dwarf_Addr highpc;
Dwarf_Addr lowpc; // start of the function
Dwarf_Addr highpc; // next address after the end of the function
Dwarf_Die* die; // DWARF DIE containing definition of the function
std::string name; // function's name
SC_ListHead params; // array of function's parameters
unw_word_t pc; // pointer to the start of the function
SC_ListHead params; // function's parameters
unw_word_t pc; // address between lowpc & highpc (plus base address offset). actually, currently executed command
unw_cursor_t cursor; // copy of stack state of the function
int line; // line in code where function is defined
std::string file; // file name (DWARF Compilation Unit) where is function defined
pst_context* ctx;
std::string file; // file name (DWARF Compilation Unit) where function is defined
pst_function* parent; // parent function in call trace (caller)
pst_context* ctx; // context of unwinding
} pst_function;
typedef struct __pst_handler {
@@ -134,10 +139,11 @@ typedef struct __pst_handler {
}
void clear();
pst_function* add_function();
pst_function* add_function(__pst_function* fun);
void del_function(pst_function* f);
pst_function* next_function(pst_function* f);
bool handle_dwarf();
void print_dwarf();
bool unwind();
bool get_frame();