labath created this revision.
labath added a reviewer: jasonmolenda.
labath added a subscriber: lldb-commits.
This adds the knowledge of the DW_CFA_GNU_args_size instruction to the eh_frame
parsing code.
Right now it is ignored as I am unsure how is it supposed to be handled, but
now we are at least
able to parse the rest of the FDE containing this instruction.
I also add a fix for a bug which was exposed by this instruction. Namely, a
mismatched sequence
of remember/restore instructions in the input could cause us to pop an empty
stack and crash. Now
we just log the error and ignore the offending instruction.
http://reviews.llvm.org/D22266
Files:
source/Symbol/DWARFCallFrameInfo.cpp
Index: source/Symbol/DWARFCallFrameInfo.cpp
===================================================================
--- source/Symbol/DWARFCallFrameInfo.cpp
+++ source/Symbol/DWARFCallFrameInfo.cpp
@@ -408,6 +408,7 @@
bool
DWARFCallFrameInfo::FDEToUnwindPlan (dw_offset_t dwarf_offset, Address
startaddr, UnwindPlan& unwind_plan)
{
+ Log *log = GetLogIfAllCategoriesSet(LIBLLDB_LOG_UNWIND);
lldb::offset_t offset = dwarf_offset;
lldb::offset_t current_entry = offset;
@@ -648,13 +649,32 @@
// the stack and place them in the current row. (This
operation is
// useful for compilers that move epilogue code into
the body of a
// function.)
+ if (stack.empty())
+ {
+ if (log)
+ log->Printf(
+ "DWARFCallFrameInfo::%s(dwarf_offset: %"
PRIx32 ", startaddr: %" PRIx64
+ " encountered DW_CFA_restore_state but
state stack is empty. Corrupt unwind info?",
+ __FUNCTION__, dwarf_offset,
startaddr.GetFileAddress());
+ break;
+ }
lldb::addr_t offset = row->GetOffset ();
row = stack.back ();
stack.pop_back ();
row->SetOffset (offset);
break;
}
+ case DW_CFA_GNU_args_size: // 0x2e
+ {
+ // The DW_CFA_GNU_args_size instruction takes an
unsigned LEB128 operand
+ // representing an argument size. This instruction
specifies the total of
+ // the size of the arguments which have been pushed
onto the stack.
+
+ // TODO: Figure out how we should handle this.
+ m_cfi_data.GetULEB128(&offset);
+ }
+
case DW_CFA_val_offset : // 0x14
case DW_CFA_val_offset_sf : // 0x15
default:
Index: source/Symbol/DWARFCallFrameInfo.cpp
===================================================================
--- source/Symbol/DWARFCallFrameInfo.cpp
+++ source/Symbol/DWARFCallFrameInfo.cpp
@@ -408,6 +408,7 @@
bool
DWARFCallFrameInfo::FDEToUnwindPlan (dw_offset_t dwarf_offset, Address startaddr, UnwindPlan& unwind_plan)
{
+ Log *log = GetLogIfAllCategoriesSet(LIBLLDB_LOG_UNWIND);
lldb::offset_t offset = dwarf_offset;
lldb::offset_t current_entry = offset;
@@ -648,13 +649,32 @@
// the stack and place them in the current row. (This operation is
// useful for compilers that move epilogue code into the body of a
// function.)
+ if (stack.empty())
+ {
+ if (log)
+ log->Printf(
+ "DWARFCallFrameInfo::%s(dwarf_offset: %" PRIx32 ", startaddr: %" PRIx64
+ " encountered DW_CFA_restore_state but state stack is empty. Corrupt unwind info?",
+ __FUNCTION__, dwarf_offset, startaddr.GetFileAddress());
+ break;
+ }
lldb::addr_t offset = row->GetOffset ();
row = stack.back ();
stack.pop_back ();
row->SetOffset (offset);
break;
}
+ case DW_CFA_GNU_args_size: // 0x2e
+ {
+ // The DW_CFA_GNU_args_size instruction takes an unsigned LEB128 operand
+ // representing an argument size. This instruction specifies the total of
+ // the size of the arguments which have been pushed onto the stack.
+
+ // TODO: Figure out how we should handle this.
+ m_cfi_data.GetULEB128(&offset);
+ }
+
case DW_CFA_val_offset : // 0x14
case DW_CFA_val_offset_sf : // 0x15
default:
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