diff options
Diffstat (limited to 'gcc/frame.c')
| -rw-r--r-- | gcc/frame.c | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/gcc/frame.c b/gcc/frame.c index b3d30c86f5e..b5f643e7043 100644 --- a/gcc/frame.c +++ b/gcc/frame.c @@ -46,7 +46,6 @@ Boston, MA 02111-1307, USA. */ #include "defaults.h" #ifdef DWARF2_UNWIND_INFO -#include "gansidecl.h" #include "dwarf2.h" #include <stddef.h> #include "frame.h" @@ -71,6 +70,25 @@ typedef unsigned int uaddr __attribute__ ((mode (pointer))); typedef int saddr __attribute__ ((mode (pointer))); typedef unsigned char ubyte; +/* Terminology: + CIE - Common Information Element + FDE - Frame Descriptor Element + + There is one per function, and it describes where the function code + is located, and what the register lifetimes and stack layout are + within the function. + + The data structures are defined in the DWARF specfication, although + not in a very readable way (see LITERATURE). + + Every time an exception is thrown, the code needs to locate the FDE + for the current function, and starts to look for exception regions + from that FDE. This works in a two-level search: + a) in a linear search, find the shared image (i.e. DLL) containing + the PC + b) using the FDE table for that shared object, locate the FDE using + binary search (which requires the sorting). */ + /* The first few fields of a CIE. The CIE_id field is 0 for a CIE, to distinguish it from a valid FDE. FDEs are aligned to an addressing unit boundary, but the fields within are unaligned. */ |