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dwarf-assembly
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Use max(uintptr_t) as error, not assert(0)

This commit is contained in:
Théophile Bastian 2018-06-13 19:13:33 +02:00
parent d53fcd22c6
commit 81b3419690
2 changed files with 41 additions and 12 deletions
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50
src/CodeGenerator.cpp
View File

@ -4,9 +4,13 @@
#include <algorithm>
#include <limits>
#include <exception>
#include <sstream>
using namespace std;
class UnhandledRegister: public std::exception {};
static const char* PRELUDE =
"#include <assert.h>\n"
"\n"
@ -24,6 +28,16 @@ CodeGenerator::CodeGenerator(
}
}
static std::string undefined_register() {
static std::string val = "";
if(val.empty()) {
std::ostringstream oss;
oss << std::numeric_limits<uintptr_t>::max() << "ull";
val = oss.str();
}
return val;
}
void CodeGenerator::generate() {
gen_of_dwarf();
}
@ -77,7 +91,11 @@ void CodeGenerator::gen_unwind_func_header(const std::string& name) {
}
void CodeGenerator::gen_unwind_func_footer() {
os << "\t\tdefault: assert(0);\n"
os << "\t\tdefault:\n"
<< "\t\t\tout_ctx.rsp = " << undefined_register() << ";\n"
<< "\t\t\tout_ctx.rbp = " << undefined_register() << ";\n"
<< "\t\t\tout_ctx.rip = " << undefined_register() << ";\n"
<< "\t\t\treturn out_ctx;"
<< "\t}\n"
<< "}" << endl;
}
@ -109,17 +127,24 @@ void CodeGenerator::gen_of_row(
{
gen_case(row.ip, row_end);
os << "\t\t\t" << "out_ctx.rsp = ";
gen_of_reg(row.cfa);
os << ';' << endl;
try {
os << "\t\t\t" << "out_ctx.rsp = ";
gen_of_reg(row.cfa);
os << ';' << endl;
os << "\t\t\t" << "out_ctx.rbp = ";
gen_of_reg(row.rbp);
os << ';' << endl;
os << "\t\t\t" << "out_ctx.rbp = ";
gen_of_reg(row.rbp);
os << ';' << endl;
os << "\t\t\t" << "out_ctx.rip = ";
gen_of_reg(row.ra);
os << ';' << endl;
os << "\t\t\t" << "out_ctx.rip = ";
gen_of_reg(row.ra);
os << ';' << endl;
} catch(const UnhandledRegister& exn) {
os << ";\n"
<< "\t\t\tout_ctx.rip = " << undefined_register() << ";\n"
<< "\t\t\tout_ctx.rsp = " << undefined_register() << ";\n"
<< "\t\t\tout_ctx.rbp = " << undefined_register() << ";\n";
}
os << "\t\t\treturn " << "out_ctx" << ";" << endl;
}
@ -166,7 +191,7 @@ static const char* ctx_of_dw_name(SimpleDwarf::MachineRegister reg) {
void CodeGenerator::gen_of_reg(const SimpleDwarf::DwRegister& reg) {
switch(reg.type) {
case SimpleDwarf::DwRegister::REG_UNDEFINED:
os << std::numeric_limits<uintptr_t>::max() << "ull";
os << undefined_register();
break;
case SimpleDwarf::DwRegister::REG_REGISTER:
os << ctx_of_dw_name(reg.reg)
@ -186,7 +211,8 @@ void CodeGenerator::gen_of_reg(const SimpleDwarf::DwRegister& reg) {
break;
}
case SimpleDwarf::DwRegister::REG_NOT_IMPLEMENTED:
os << "0; assert(0)";
os << "0";
throw UnhandledRegister();
break;
}
}

3
stack_walker/stack_walker.cpp
View File

@ -228,6 +228,9 @@ bool unwind_context(unwind_context_t& ctx) {
uintptr_t tr_pc = ctx.rip - mmap_entry->beg;
ctx = fde_func(ctx, tr_pc);
if(ctx.rip + 1 == 0 && ctx.rsp + 1 == 0 && ctx.rbp + 1 == 0) // no entry
return false;
return true;
}