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Adds a DW_OP_call_frame_cfa handler when evaluating DWARF 3/4 expressions 

in LLDB that load the canonical frame address rather than a location list.

- Handles the simple case where a CFA can be pulled from the current stack frame.
- Fixes more than one hundred failing tests with gcc 4.8!

TODO: Use UnwindPlan::GetRowForFunctionOffset if the DWARFExpression needs
to be evaluated in a context analogous to a virtual unwind (perhaps using RegisterContextLLDB).

- Also adds some comments to DWARFCallFrameInfo whenever I got confused.

llvm-svn: 187361
This commit is contained in:
Ashok Thirumurthi 2013-07-29 16:05:11 +00:00
parent a3eede2cc2
commit 6e264d39dc
2 changed files with 34 additions and 1 deletions
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32
lldb/source/Expression/DWARFExpression.cpp
View File

@ -37,6 +37,7 @@
#include "lldb/Target/Process.h"
#include "lldb/Target/RegisterContext.h"
#include "lldb/Target/StackFrame.h"
#include "lldb/Target/StackID.h"
using namespace lldb;
using namespace lldb_private;
@ -2627,6 +2628,37 @@ DWARFExpression::Evaluate
case DW_OP_stack_value:
stack.back().SetValueType(Value::eValueTypeScalar);
break;
//----------------------------------------------------------------------
// OPCODE: DW_OP_call_frame_cfa
// OPERANDS: None
// DESCRIPTION: Specifies a DWARF expression that pushes the value of
// the canonical frame address consistent with the call frame information
// located in .debug_frame (or in the FDEs of the eh_frame section).
//----------------------------------------------------------------------
case DW_OP_call_frame_cfa:
if (frame)
{
// Note that we don't have to parse FDEs because this DWARF expression
// is commonly evaluated with a valid stack frame.
StackID id = frame->GetStackID();
addr_t cfa = id.GetCallFrameAddress();
if (cfa != LLDB_INVALID_ADDRESS)
{
stack.push_back(Scalar(cfa));
stack.back().SetValueType (Value::eValueTypeHostAddress);
}
else
if (error_ptr)
error_ptr->SetErrorString ("Stack frame does not include a canonical frame address for DW_OP_call_frame_cfa opcode.");
}
else
{
if (error_ptr)
error_ptr->SetErrorString ("Invalid stack frame in context for DW_OP_call_frame_cfa opcode.");
return false;
}
break;
}
}

3
lldb/source/Symbol/DWARFCallFrameInfo.cpp
View File

@ -155,7 +155,7 @@ DWARFCallFrameInfo::ParseCIE (const dw_offset_t cie_offset)
// cie.offset = cie_offset;
// cie.length = length;
// cie.cieID = cieID;
cie_sp->ptr_encoding = DW_EH_PE_absptr;
cie_sp->ptr_encoding = DW_EH_PE_absptr; // default
cie_sp->version = m_cfi_data.GetU8(&offset);
for (i=0; i<CFI_AUG_MAX_SIZE; ++i)
@ -233,6 +233,7 @@ DWARFCallFrameInfo::ParseCIE (const dw_offset_t cie_offset)
// Data shall include a 1 byte argument that
// represents the pointer encoding for the address
// pointers used in the FDE.
// Example: 0x1B == DW_EH_PE_pcrel | DW_EH_PE_sdata4
cie_sp->ptr_encoding = m_cfi_data.GetU8(&offset);
break;
}