add comments

From-SVN: r50805
This commit is contained in:
Jason Merrill 2002-03-15 05:18:21 -05:00
parent 98ef4163bc
commit 81a60e6ca0
2 changed files with 19 additions and 2 deletions

View File

@ -48,7 +48,9 @@
#define PRE_GCC3_DWARF_FRAME_REGISTERS DWARF_FRAME_REGISTERS
#endif
/* This is the register and unwind state for a particular frame. */
/* This is the register and unwind state for a particular frame. This
provides the information necessary to unwind up past a frame and return
to its caller. */
struct _Unwind_Context
{
void *reg[DWARF_FRAME_REGISTERS+1];
@ -889,6 +891,11 @@ execute_cfa_program (const unsigned char *insn_ptr,
}
}
/* Given the _Unwind_Context CONTEXT for a stack frame, look up the FDE for
its caller and decode it into FS. This function also sets the
args_size and lsda members of CONTEXT, as they are really information
about the caller's frame. */
static _Unwind_Reason_Code
uw_frame_state_for (struct _Unwind_Context *context, _Unwind_FrameState *fs)
{
@ -1083,6 +1090,11 @@ uw_update_context_1 (struct _Unwind_Context *context, _Unwind_FrameState *fs)
}
}
/* CONTEXT describes the unwind state for a frame, and FS describes the FDE
of its caller. Update CONTEXT to refer to the caller as well. Note
that the args_size and lsda members are not updated here, but later in
uw_frame_state_for. */
static void
uw_update_context (struct _Unwind_Context *context, _Unwind_FrameState *fs)
{

View File

@ -72,7 +72,6 @@ _Unwind_RaiseException_Phase2(struct _Unwind_Exception *exc,
return code;
}
/* Raise an exception, passing along the given exception object. */
_Unwind_Reason_Code
@ -81,6 +80,7 @@ _Unwind_RaiseException(struct _Unwind_Exception *exc)
struct _Unwind_Context this_context, cur_context;
_Unwind_Reason_Code code;
/* Set up this_context to describe the current stack frame. */
uw_init_context (&this_context);
cur_context = this_context;
@ -90,6 +90,8 @@ _Unwind_RaiseException(struct _Unwind_Exception *exc)
{
_Unwind_FrameState fs;
/* Set up fs to describe the FDE for the caller of cur_context. The
first time through the loop, that means __cxa_throw. */
code = uw_frame_state_for (&cur_context, &fs);
if (code == _URC_END_OF_STACK)
@ -112,6 +114,7 @@ _Unwind_RaiseException(struct _Unwind_Exception *exc)
return _URC_FATAL_PHASE1_ERROR;
}
/* Update cur_context to describe the same frame as fs. */
uw_update_context (&cur_context, &fs);
}
@ -144,6 +147,7 @@ _Unwind_ForcedUnwind_Phase2(struct _Unwind_Exception *exc,
_Unwind_FrameState fs;
int action;
/* Set up fs to describe the FDE for the caller of cur_context. */
code = uw_frame_state_for (context, &fs);
if (code != _URC_NO_REASON && code != _URC_END_OF_STACK)
return _URC_FATAL_PHASE2_ERROR;
@ -172,6 +176,7 @@ _Unwind_ForcedUnwind_Phase2(struct _Unwind_Exception *exc,
return _URC_FATAL_PHASE2_ERROR;
}
/* Update cur_context to describe the same frame as fs. */
uw_update_context (context, &fs);
}