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Add support for frameless function compact unwind encodings on x86_64/i386. 

This completes the compact unwind support for x86 targets.  

I'm still skipping the UNWIND_X86_64_MODE_STACK_IND encodings for
x86_64 right now because clang was emitting bad data for this form
until it was fixed in r217020 circa Sep 2014.

arm64 parsing still needs to be added.

llvm-svn: 224698
This commit is contained in:
Jason Molenda 2014-12-22 11:02:02 +00:00
parent 732b128129
commit 19ba9fbf27
1 changed files with 214 additions and 46 deletions
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260
lldb/source/Symbol/CompactUnwindInfo.cpp
View File

@ -759,46 +759,63 @@ CompactUnwindInfo::CreateUnwindPlan_x86_64 (Target &target, FunctionInfo &functi
case UNWIND_X86_64_MODE_STACK_IND:
{
// The clang in Xcode 6 is emitting incorrect compact unwind encodings for this
// style of unwind. It was fixed in llvm r217020 although the algorith being
// used to compute this style of unwind in generateCompactUnwindEncodingImpl()
// isn't as foolproof as I'm comfortable with -- if any instructions other than
// a push are scheduled before the subq, it will give bogus encoding results.
// The target and pc_or_function_start arguments will be needed to handle this
// encoding style correctly -- to find the start address of the function and
// read memory offset from there.
// style of unwind. It was fixed in llvm r217020.
return false;
}
break;
#if 0
case UNWIND_X86_64_MODE_STACK_IMMD:
{
uint32_t stack_size = EXTRACT_BITS (encoding, UNWIND_X86_64_FRAMELESS_STACK_SIZE);
uint32_t register_count = EXTRACT_BITS (encoding, UNWIND_X86_64_FRAMELESS_STACK_REG_COUNT);
uint32_t permutation = EXTRACT_BITS (encoding, UNWIND_X86_64_FRAMELESS_STACK_REG_PERMUTATION);
uint32_t stack_size = EXTRACT_BITS (function_info.encoding, UNWIND_X86_64_FRAMELESS_STACK_SIZE);
uint32_t register_count = EXTRACT_BITS (function_info.encoding, UNWIND_X86_64_FRAMELESS_STACK_REG_COUNT);
uint32_t permutation = EXTRACT_BITS (function_info.encoding, UNWIND_X86_64_FRAMELESS_STACK_REG_PERMUTATION);
if (mode == UNWIND_X86_64_MODE_STACK_IND && function_start)
if (mode == UNWIND_X86_64_MODE_STACK_IND && function_info.valid_range_offset_start != 0)
{
uint32_t stack_adjust = EXTRACT_BITS (encoding, UNWIND_X86_64_FRAMELESS_STACK_ADJUST);
uint32_t stack_adjust = EXTRACT_BITS (function_info.encoding, UNWIND_X86_64_FRAMELESS_STACK_ADJUST);
// offset into the function instructions; 0 == beginning of first instruction
uint32_t offset_to_subl_insn = EXTRACT_BITS (encoding, UNWIND_X86_64_FRAMELESS_STACK_SIZE);
uint32_t offset_to_subl_insn = EXTRACT_BITS (function_info.encoding, UNWIND_X86_64_FRAMELESS_STACK_SIZE);
stack_size = *((uint32_t*) (function_start + offset_to_subl_insn));
stack_size += stack_adjust * 8;
printf ("large stack ");
SectionList *sl = m_objfile.GetSectionList ();
if (sl)
{
ProcessSP process_sp = target.GetProcessSP();
if (process_sp)
{
Address subl_payload_addr (function_info.valid_range_offset_start, sl);
subl_payload_addr.Slide (offset_to_subl_insn);
Error error;
uint64_t large_stack_size = process_sp->ReadUnsignedIntegerFromMemory (subl_payload_addr.GetLoadAddress (&target),
4, 0, error);
if (large_stack_size != 0 && error.Success ())
{
// Got the large stack frame size correctly - use it
stack_size = large_stack_size + (stack_adjust * wordsize);
}
else
{
return false;
}
}
else
{
return false;
}
}
else
{
return false;
}
}
printf ("frameless function: stack size %d, register count %d ", stack_size * 8, register_count);
if (register_count == 0)
{
printf (" no registers saved");
}
else
row->SetCFARegister (x86_64_eh_regnum::rsp);
row->SetCFAOffset (stack_size * wordsize);
row->SetOffset (0);
row->SetRegisterLocationToAtCFAPlusOffset (x86_64_eh_regnum::rip, wordsize * -1, true);
row->SetRegisterLocationToIsCFAPlusOffset (x86_64_eh_regnum::rsp, 0, true);
if (register_count > 0)
{
// We need to include (up to) 6 registers in 10 bits.
@ -887,11 +904,7 @@ CompactUnwindInfo::CreateUnwindPlan_x86_64 (Target &target, FunctionInfo &functi
}
}
printf (" CFA is rsp+%d ", stack_size * 8);
uint32_t saved_registers_offset = 1;
printf (" rip=[CFA-%d]", saved_registers_offset * 8);
saved_registers_offset++;
for (int i = (sizeof (registers) / sizeof (int)) - 1; i >= 0; i--)
@ -901,32 +914,21 @@ CompactUnwindInfo::CreateUnwindPlan_x86_64 (Target &target, FunctionInfo &functi
case UNWIND_X86_64_REG_NONE:
break;
case UNWIND_X86_64_REG_RBX:
printf (" rbx=[CFA-%d]", saved_registers_offset * 8);
break;
case UNWIND_X86_64_REG_R12:
printf (" r12=[CFA-%d]", saved_registers_offset * 8);
break;
case UNWIND_X86_64_REG_R13:
printf (" r13=[CFA-%d]", saved_registers_offset * 8);
break;
case UNWIND_X86_64_REG_R14:
printf (" r14=[CFA-%d]", saved_registers_offset * 8);
break;
case UNWIND_X86_64_REG_R15:
printf (" r15=[CFA-%d]", saved_registers_offset * 8);
break;
case UNWIND_X86_64_REG_RBP:
printf (" rbp=[CFA-%d]", saved_registers_offset * 8);
break;
row->SetRegisterLocationToAtCFAPlusOffset (translate_to_eh_frame_regnum_x86_64 (registers[i]), wordsize * -saved_registers_offset, true);
break;
}
saved_registers_offset++;
}
}
unwind_plan.AppendRow (row);
return true;
}
break;
#endif
case UNWIND_X86_64_MODE_DWARF:
{
@ -1037,6 +1039,172 @@ CompactUnwindInfo::CreateUnwindPlan_i386 (Target &target, FunctionInfo &function
case UNWIND_X86_MODE_STACK_IND:
case UNWIND_X86_MODE_STACK_IMMD:
{
uint32_t stack_size = EXTRACT_BITS (function_info.encoding, UNWIND_X86_FRAMELESS_STACK_SIZE);
uint32_t register_count = EXTRACT_BITS (function_info.encoding, UNWIND_X86_FRAMELESS_STACK_REG_COUNT);
uint32_t permutation = EXTRACT_BITS (function_info.encoding, UNWIND_X86_FRAMELESS_STACK_REG_PERMUTATION);
if (mode == UNWIND_X86_MODE_STACK_IND && function_info.valid_range_offset_start != 0)
{
uint32_t stack_adjust = EXTRACT_BITS (function_info.encoding, UNWIND_X86_FRAMELESS_STACK_ADJUST);
// offset into the function instructions; 0 == beginning of first instruction
uint32_t offset_to_subl_insn = EXTRACT_BITS (function_info.encoding, UNWIND_X86_FRAMELESS_STACK_SIZE);
SectionList *sl = m_objfile.GetSectionList ();
if (sl)
{
ProcessSP process_sp = target.GetProcessSP();
if (process_sp)
{
Address subl_payload_addr (function_info.valid_range_offset_start, sl);
subl_payload_addr.Slide (offset_to_subl_insn);
Error error;
uint64_t large_stack_size = process_sp->ReadUnsignedIntegerFromMemory (subl_payload_addr.GetLoadAddress (&target),
4, 0, error);
if (large_stack_size != 0 && error.Success ())
{
// Got the large stack frame size correctly - use it
stack_size = large_stack_size + (stack_adjust * wordsize);
}
else
{
return false;
}
}
else
{
return false;
}
}
else
{
return false;
}
}
row->SetCFARegister (i386_eh_regnum::esp);
row->SetCFAOffset (stack_size * wordsize);
row->SetOffset (0);
row->SetRegisterLocationToAtCFAPlusOffset (i386_eh_regnum::eip, wordsize * -1, true);
row->SetRegisterLocationToIsCFAPlusOffset (i386_eh_regnum::esp, 0, true);
if (register_count > 0)
{
// We need to include (up to) 6 registers in 10 bits.
// That would be 18 bits if we just used 3 bits per reg to indicate
// the order they're saved on the stack.
//
// This is done with Lehmer code permutation, e.g. see
// http://stackoverflow.com/questions/1506078/fast-permutation-number-permutation-mapping-algorithms
int permunreg[6];
// This decodes the variable-base number in the 10 bits
// and gives us the Lehmer code sequence which can then
// be decoded.
switch (register_count)
{
case 6:
permunreg[0] = permutation/120; // 120 == 5!
permutation -= (permunreg[0]*120);
permunreg[1] = permutation/24; // 24 == 4!
permutation -= (permunreg[1]*24);
permunreg[2] = permutation/6; // 6 == 3!
permutation -= (permunreg[2]*6);
permunreg[3] = permutation/2; // 2 == 2!
permutation -= (permunreg[3]*2);
permunreg[4] = permutation; // 1 == 1!
permunreg[5] = 0;
break;
case 5:
permunreg[0] = permutation/120;
permutation -= (permunreg[0]*120);
permunreg[1] = permutation/24;
permutation -= (permunreg[1]*24);
permunreg[2] = permutation/6;
permutation -= (permunreg[2]*6);
permunreg[3] = permutation/2;
permutation -= (permunreg[3]*2);
permunreg[4] = permutation;
break;
case 4:
permunreg[0] = permutation/60;
permutation -= (permunreg[0]*60);
permunreg[1] = permutation/12;
permutation -= (permunreg[1]*12);
permunreg[2] = permutation/3;
permutation -= (permunreg[2]*3);
permunreg[3] = permutation;
break;
case 3:
permunreg[0] = permutation/20;
permutation -= (permunreg[0]*20);
permunreg[1] = permutation/4;
permutation -= (permunreg[1]*4);
permunreg[2] = permutation;
break;
case 2:
permunreg[0] = permutation/5;
permutation -= (permunreg[0]*5);
permunreg[1] = permutation;
break;
case 1:
permunreg[0] = permutation;
break;
}
// Decode the Lehmer code for this permutation of
// the registers v. http://en.wikipedia.org/wiki/Lehmer_code
int registers[6];
bool used[7] = { false, false, false, false, false, false, false };
for (int i = 0; i < register_count; i++)
{
int renum = 0;
for (int j = 1; j < 7; j++)
{
if (used[j] == false)
{
if (renum == permunreg[i])
{
registers[i] = j;
used[j] = true;
break;
}
renum++;
}
}
}
uint32_t saved_registers_offset = 1;
saved_registers_offset++;
for (int i = (sizeof (registers) / sizeof (int)) - 1; i >= 0; i--)
{
switch (registers[i])
{
case UNWIND_X86_REG_NONE:
break;
case UNWIND_X86_REG_EBX:
case UNWIND_X86_REG_ECX:
case UNWIND_X86_REG_EDX:
case UNWIND_X86_REG_EDI:
case UNWIND_X86_REG_ESI:
case UNWIND_X86_REG_EBP:
row->SetRegisterLocationToAtCFAPlusOffset (translate_to_eh_frame_regnum_i386 (registers[i]), wordsize * -saved_registers_offset, true);
break;
}
saved_registers_offset++;
}
}
unwind_plan.AppendRow (row);
return true;
}
break;
case UNWIND_X86_MODE_DWARF:
{
return false;