diff options
Diffstat (limited to 'gcc/ada/s-mastop.ads')
| -rw-r--r-- | gcc/ada/s-mastop.ads | 69 |
1 files changed, 2 insertions, 67 deletions
diff --git a/gcc/ada/s-mastop.ads b/gcc/ada/s-mastop.ads index 8ee412c2ff1..95f0da5da8b 100644 --- a/gcc/ada/s-mastop.ads +++ b/gcc/ada/s-mastop.ads @@ -6,7 +6,7 @@ -- -- -- S p e c -- -- -- --- Copyright (C) 1999-2001 Free Software Foundation, Inc. -- +-- Copyright (C) 1999-2005 Free Software Foundation, Inc. -- -- -- -- GNAT is free software; you can redistribute it and/or modify it under -- -- terms of the GNU General Public License as published by the Free Soft- -- @@ -36,7 +36,6 @@ pragma Polling (Off); -- elaboration circularities with System.Exception_Tables. with System.Storage_Elements; -with System.Exceptions; package System.Machine_State_Operations is @@ -79,65 +78,11 @@ package System.Machine_State_Operations is -- outer level, or some other frame for which no information can be -- provided. - procedure Pop_Frame - (M : Machine_State; - Info : System.Exceptions.Subprogram_Info_Type); + procedure Pop_Frame (M : Machine_State); -- This procedure pops the machine state M so that it represents the -- call point, as though the current subprogram had returned. It -- changes only the value referenced by M, and does not affect -- the current stack environment. - -- - -- The Info parameter represents information generated by the backend - -- (see description of Subprogram_Info node in sinfo.ads). This - -- information is stored as static data during compilation. The - -- caller then passes this information to Pop_Frame, which will - -- use it to determine what must be changed in the machine state - -- (e.g. which save-over-call registers must be restored, and from - -- where on the stack frame they must be restored). - -- - -- A value of No_Info for Info means either that the backend provided - -- no information for current frame, or that the current frame is an - -- other language frame for which no information exists, or that this - -- is an outer level subprogram. In any case, Pop_Frame sets the code - -- location to Null_Address when it pops past such a frame, and this - -- is taken as an indication that the exception is unhandled. - - -- Note: at the current time, Info, if present is always a copy of - -- the entry point of the procedure, as found by searching the - -- subprogram table. For the case where a procedure is indeed in - -- the table (either it is an Ada procedure, or a foreign procedure - -- which is registered using pragma Propagate_Exceptions), then the - -- entry point information will indeed be correct. It may well be - -- possible for Pop_Frame to avoid using the Info parameter (for - -- example if it consults auxiliary Dwarf tables to do its job). - -- This is desirable if it can be done, because it means that it - -- will work fine to propagate exceptions through unregistered - -- foreign procedures. What will happen is that the search in the - -- Ada subprogram table will find a junk entry. Even if this junk - -- entry has an exception table, none of them will apply to the - -- current location, so they will be ignored, and then Pop_Frame - -- will be called to pop the frame. The Info parameter for this - -- call will be junk, but if it is not used that does not matter. - -- Note that the address recorded in the traceback table is of - -- the exception location, so the traceback will be correct even - -- in this case. - - procedure Enter_Handler - (M : Machine_State; - Handler : System.Exceptions.Handler_Loc); - -- When Propagate_Handler locates an applicable exception handler, it - -- calls Enter_Handler, passing it two parameters. The first is the - -- machine state that corresponds to what is required for entry to - -- the handler, as computed by repeated Pop_Frame calls to reach the - -- handler to be entered. The second is the code location for the - -- handler itself which is the address of the label at the start of - -- the handler code. - -- - -- Note: The machine state M is likely stored on the part of the - -- stack that will be popped by the call, so care must be taken - -- not to pop the stack until the Machine_State is entirely read. - -- The value passed as Handler was obtained from elaboration of - -- an N_Handler_Loc node by the backend. function Fetch_Code (Loc : Code_Loc) return Code_Loc; -- Some architectures (notably VMS) use a descriptor to describe @@ -150,14 +95,4 @@ package System.Machine_State_Operations is -- This routine sets M from the current machine state. It is called -- when an exception is initially signalled to initialize the state. - procedure Set_Signal_Machine_State - (M : Machine_State; - Context : System.Address); - -- This routine sets M from the machine state that corresponds to the - -- point in the code where a signal was raised. The parameter Context - -- is a pointer to a structure created by the operating system when a - -- signal is raised, and made available to the signal handler. The - -- format of this context block, and the manner in which it is made - -- available to the handler, are implementation dependent. - end System.Machine_State_Operations; |