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Have AssemblyParse_x86::get_non_call_site_unwind_plan track 

which registers have been spilled (saved to the stack) - and
if we see that same register being saved to the stack again,
don't record that, it's something specific to this stack frame.

I found a code sequence for i386 where clang did a push %esi
and then later in the function it did movl %esi, -0x7c(%ebp)
and that second save of a scratch value overrode the original
push location.

<rdar://problem/19171178> 

llvm-svn: 225431
This commit is contained in:
Jason Molenda 2015-01-08 06:41:12 +00:00
parent a257ab0803
commit 4535ecb1f3
1 changed files with 13 additions and 2 deletions
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15
lldb/source/Plugins/UnwindAssembly/x86/UnwindAssembly-x86.cpp
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@ -638,6 +638,12 @@ AssemblyParse_x86::get_non_call_site_unwind_plan (UnwindPlan &unwind_plan)
*newrow = *row.get();
row.reset(newrow);
// Track which registers have been saved so far in the prologue.
// If we see another push of that register, it's not part of the prologue.
// The register numbers used here are the machine register #'s
// (i386_register_numbers, x86_64_register_numbers).
std::vector<bool> saved_registers(32, false);
const bool prefer_file_cache = true;
Target *target = m_exe_ctx.GetTargetPtr();
@ -707,12 +713,15 @@ AssemblyParse_x86::get_non_call_site_unwind_plan (UnwindPlan &unwind_plan)
row->SetCFAOffset (current_sp_bytes_offset_from_cfa);
}
// record where non-volatile (callee-saved, spilled) registers are saved on the stack
if (nonvolatile_reg_p (machine_regno) && machine_regno_to_lldb_regno (machine_regno, lldb_regno))
if (nonvolatile_reg_p (machine_regno)
&& machine_regno_to_lldb_regno (machine_regno, lldb_regno)
&& saved_registers[machine_regno] == false)
{
need_to_push_row = true;
UnwindPlan::Row::RegisterLocation regloc;
regloc.SetAtCFAPlusOffset (-current_sp_bytes_offset_from_cfa);
row->SetRegisterInfo (lldb_regno, regloc);
saved_registers[machine_regno] = true;
}
if (need_to_push_row)
{
@ -728,8 +737,10 @@ AssemblyParse_x86::get_non_call_site_unwind_plan (UnwindPlan &unwind_plan)
if (mov_reg_to_local_stack_frame_p (machine_regno, stack_offset) && nonvolatile_reg_p (machine_regno))
{
if (machine_regno_to_lldb_regno (machine_regno, lldb_regno))
if (machine_regno_to_lldb_regno (machine_regno, lldb_regno) && saved_registers[machine_regno] == false)
{
saved_registers[machine_regno] = true;
row->SetOffset (current_func_text_offset + insn_len);
UnwindPlan::Row::RegisterLocation regloc;