[Lldb-commits] [lldb] r225431 - Have AssemblyParse_x86::get_non_call_site_unwind_plan track
Jason Molenda
jmolenda at apple.com
Wed Jan 7 22:41:12 PST 2015
Author: jmolenda
Date: Thu Jan 8 00:41:12 2015
New Revision: 225431
URL: http://llvm.org/viewvc/llvm-project?rev=225431&view=rev
Log:
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>
Modified:
lldb/trunk/source/Plugins/UnwindAssembly/x86/UnwindAssembly-x86.cpp
Modified: lldb/trunk/source/Plugins/UnwindAssembly/x86/UnwindAssembly-x86.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/UnwindAssembly/x86/UnwindAssembly-x86.cpp?rev=225431&r1=225430&r2=225431&view=diff
==============================================================================
--- lldb/trunk/source/Plugins/UnwindAssembly/x86/UnwindAssembly-x86.cpp (original)
+++ lldb/trunk/source/Plugins/UnwindAssembly/x86/UnwindAssembly-x86.cpp Thu Jan 8 00:41:12 2015
@@ -638,6 +638,12 @@ AssemblyParse_x86::get_non_call_site_unw
*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_unw
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_unw
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;
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