--gpc-rts=-trap-on-error - Gpc

19 Dec 2005

The below patch adds --gpc-rts=-trap-on-error (aka --gpc-rts=-t) to  
the gpc runtime lib.
This is quite useful
* when debugging with gdb
* when debugging with visual front-ends to gdb
* on systems where WriteStackDump does nothing
* on systems that automatically report and log backtraces (like Darwin).
diff -ur gcc-3.4.5-orig/gcc/p/rts/error.pas gcc-3.4.5/gcc/p/rts/ 
error.pas

--- gcc-3.4.5-orig/gcc/p/rts/error.pas	2005-12-15 17:41:59.000000000  
+0100
+++ gcc-3.4.5/gcc/p/rts/error.pas	2005-12-19 17:09:15.000000000 +0100
@@ -95,6 +95,7 @@
    RTSOptions: Integer = 0; attribute (name = '_p_RTSOptions');
    RTSWarnFlag: Boolean = False; attribute (name = '_p_RTSWarnFlag');
    AbortOnError: Boolean = False; attribute (name = '_p_AbortOnError');
+  TrapOnError: Boolean = False; attribute (name = '_p_TrapOnError');
CurrentReturnAddr: Pointer = nil; attribute (name =  
'_p_CurrentReturnAddr');
    CurrentReturnAddrCounter: Integer = 0; attribute (name =  
'_p_CurrentReturnAddrCounter');
@@ -890,6 +891,19 @@
  {$endlocal}
  end;
+procedure TrapError; attribute (inline);
+begin
+{$ifdef __i386__}
+  asm("int3")
+{$else}
+{$ifdef __ppc__}
+  asm("trap")
+{$else}
+  BuiltinTrap;
+{$endif}
+{$endif}
+end;
+
  procedure EndRuntimeError (n: Integer); attribute (noreturn, name =  
'_p_EndRuntimeError');
  begin
    FinishErrorMessage (n);
@@ -898,6 +912,8 @@
    Finalize1;
    RestoreReturnAddress;
    if (RTSErrorFD >= 0) then Discard (CloseHandle (RTSErrorFD));   
{ just to be sure }
+  if TrapOnError then
+    TrapError;
    ExitProgram (RuntimeErrorExitValue, AbortOnError)
  end;
diff -ur gcc-3.4.5-orig/gcc/p/rts/init.pas gcc-3.4.5/gcc/p/rts/init.pas
--- gcc-3.4.5-orig/gcc/p/rts/init.pas	2005-12-15 17:41:59.000000000  
+0100
+++ gcc-3.4.5/gcc/p/rts/init.pas	2005-12-19 15:34:26.000000000 +0100
@@ -94,6 +94,7 @@
  -h, --help                Display this help and exit
  -v, --version             Output RTS version information and exit
  -a, --abort-on-error      Abort with SIGABRT on runtime error
+-t, --trap-on-error       Trap or break into debugger on runtime error
  -e, --eoln-hack           Toggle EOLn hack right after Reset for  
terminals
  -i LINE, --input LINE     Implicitly add LINE to the beginning of  
Input
  -n INTERNAL_NAME:EXTERNAL_NAME, --file-name[=] 
INTERNAL_NAME:EXTERNAL_NAME
@@ -117,11 +118,12 @@
function DoOption: Boolean;
    const
-    LongOptions: array [1 .. 12] of OptionType =
+    LongOptions: array [1 .. 13] of OptionType =
        ((Prefix,               NoArgument,       nil, '='),
         ('help',               NoArgument,       nil, 'h'),
         ('version',            NoArgument,       nil, 'v'),
         ('abort-on-error',     NoArgument,       nil, 'a'),
+       ('trap-on-error',      NoArgument,       nil, 't'),
         ('eoln-hack',          NoArgument,       nil, 'e'),
         ('input',              RequiredArgument, nil, 'i'),
         ('file-name',          RequiredArgument, nil, 'n'),
@@ -167,6 +169,7 @@
               Halt
             end;
        'a': AbortOnError := True;
+      't': TrapOnError := True;
        'e': EOLnResetHack := not EOLnResetHack;
        'i': begin
               { Strings written to CurrentStdIn, given as first  
standard input to user program }
diff -ur gcc-3.4.5-orig/gcc/p/rts/rts.c gcc-3.4.5/gcc/p/rts/rts.c
--- gcc-3.4.5-orig/gcc/p/rts/rts.c	2005-12-15 17:41:59.000000000 +0100
+++ gcc-3.4.5/gcc/p/rts/rts.c	2005-12-19 17:02:50.000000000 +0100
@@ -2599,6 +2599,13 @@
    #endif
  }
+GLOBAL (void _p_BuiltinTrap (void))
+{
+#if (__GNUC__ >= 3)
+  __builtin_trap();
+#endif
+}
+
  GLOBAL_ATTR (void _p_ExitProgram (int Status, Boolean AbortFlag  
UNUSED), noreturn)
  {
    #ifdef HAVE_ABORT
diff -ur gcc-3.4.5-orig/gcc/p/rts/rtsc.pas gcc-3.4.5/gcc/p/rts/rtsc.pas
--- gcc-3.4.5-orig/gcc/p/rts/rtsc.pas	2005-12-15 17:41:59.000000000  
+0100
+++ gcc-3.4.5/gcc/p/rts/rtsc.pas	2005-12-19 17:11:07.000000000 +0100
@@ -414,6 +414,7 @@
  function  CGetPwEnt (var Entries: PCPasswordEntries): CInteger;  
external name '_p_CGetPwEnt';
  procedure InitMisc; external name '_p_InitMisc';
  procedure InitMalloc (procedure WarnProc (Msg: CString)); external  
name '_p_InitMalloc';
+procedure BuiltinTrap; external name '_p_BuiltinTrap';
  procedure ExitProgram (Status: CInteger; AbortFlag: Boolean);  
attribute (noreturn); external name '_p_ExitProgram';
  {@endinternal}
Note that the Linux kernel (in bug.h) works around problems with  
__builtin_trap for some versions of gcc in combination with sparc or  
ia-64. This is done by directly emitting assembly code, just like  
TrapError does in the diff. However, I can't test sparc and ia-64, so  
something similar has not (yet) been implemented. I  did implement a  
workaround for __i386__ where __builtin_trap emits int5 instead of  
int3 (or at least that is what it does on i386-apple-darwin and that  
is what i386.md describes in gcc-3.4.5).
I hope this is useful.
Regards,
Adriaan  van Os

    