backtrace: add support for windows and for llvm (via libbacktrace).

16 files changed, 393 insertions, 30 deletions

diff --git a/src/ghdldrv/ghdlrun.adb b/src/ghdldrv/ghdlrun.adb
index eac0702..9249f2c 100644
--- a/src/ghdldrv/ghdlrun.adb
+++ b/src/ghdldrv/ghdlrun.adb
@@ -59,6 +59,7 @@ with Grt.Values;
 with Grt.Names;
 with Grt.Std_Logic_1164;
 with Grt.Errors;
+with Grt.Backtraces.Jit;
 
 with Ghdlcomp;
 with Foreigns;
@@ -591,7 +592,7 @@ package body Ghdlrun is
 
       Grtlink.Flag_String := Flags.Flag_String;
 
-      Grt.Errors.Symbolizer := Ortho_Jit.Symbolize'Access;
+      Grt.Backtraces.Jit.Symbolizer_Proc := Ortho_Jit.Symbolize'Access;
 
       Elaborate_Proc :=
         Conv (Ortho_Jit.Get_Address (Trans_Decls.Ghdl_Elaborate));
diff --git a/src/grt/Makefile.inc b/src/grt/Makefile.inc
index af217e1..f8a4d32 100644
--- a/src/grt/Makefile.inc
+++ b/src/grt/Makefile.inc
@@ -28,6 +28,8 @@
 # target: GCC target
 # GRT_FLAGS: common (Ada + C + asm) compilation flags.
 # GRT_ADAFLAGS: compilation flags for Ada
+#
+# LIBBACKTRACE: if set, path to libbacktrace.a (from gcc)
 
 # Convert the target variable into a space separated list of architecture,
 # manufacturer, and operating system and assign each of those to its own
@@ -69,6 +71,9 @@ GRT_FST_OBJS := fstapi.o lz4.o fastlz.o
 # Additionnal object files (C or asm files).
 GRT_ADD_OBJS:=$(GRT_TARGET_OBJS) grt-cbinding.o grt-cvpi.o $(GRT_FST_OBJS)
 
+# Source files create by grt.
+GRT_SRC_DEPS:=grt-backtraces-impl.ads
+
 #GRT_USE_PTHREADS=y
 ifeq ($(GRT_USE_PTHREADS),y)
  GRT_CFLAGS+=-DUSE_THREADS
@@ -76,13 +81,18 @@ ifeq ($(GRT_USE_PTHREADS),y)
  GRT_EXTRA_LIB+=-lpthread
 endif
 
+GRT_LIBBACKTRACE=
+ifneq ($(LIBBACKTRACE),)
+  GRT_LIBBACKTRACE=libbacktrace.a
+endif
+
 # Configuration pragmas.
 GRT_PRAGMA_FLAG=-gnatec$(GRTSRCDIR)/grt.adc -gnat05
 
 # Rule to compile an Ada file.
 GRT_ADACOMPILE=$(ADAC) -c $(GRT_FLAGS) $(GRT_PRAGMA_FLAG) -o $@ $<
 
-grt-all: libgrt.a grt.lst
+grt-all: libgrt.a $(GRT_LIBBACKTRACE) grt.lst
 
 libgrt.a: $(GRT_ADD_OBJS) run-bind.o main.o grt-files
 	$(RM) -f $@
@@ -90,7 +100,7 @@ libgrt.a: $(GRT_ADD_OBJS) run-bind.o main.o grt-files
 	 run-bind.o main.o
 	$(GRT_RANLIB) $@
 
-run-bind.adb: grt-force
+run-bind.adb: $(GRT_SRC_DEPS) grt-force
 	gnatmake -c -aI$(GRTSRCDIR) $(GRT_PRAGMA_FLAG) \
 	  ghdl_main $(GRT_ADAFLAGS) -cargs $(GRT_FLAGS)
 	gnatbind -Lgrt_ -o run-bind.adb -n ghdl_main.ali
@@ -142,6 +152,15 @@ fastlz.o: $(GRTSRCDIR)/fst/fastlz.c
 chkstk.o: $(GRTSRCDIR)/config/chkstk.S
 	$(CC) -c $(GRT_FLAGS) -o $@ $<
 
+grt-backtraces-impl.ads:
+ifneq ($(GRT_LIBBACKTRACE),)
+	echo "with Grt.Backtraces.Gcc;" > $@
+	echo "package Grt.Backtraces.Impl renames Grt.Backtraces.Gcc;" >> $@
+else
+	echo "with Grt.Backtraces.Jit;" > $@
+	echo "package Grt.Backtraces.Impl renames Grt.Backtraces.Jit;" >> $@
+endif
+
 grt-disp-config:
 	@echo "target: $(target)"
 	@echo "targ: $(targ)"
@@ -166,11 +185,22 @@ grt.lst: grt-files.in
 ifdef GRT_EXTRA_LIB
 	for i in $(GRT_EXTRA_LIB); do echo $$i >> $@; done
 endif
+ifneq ($(LIBBACKTRACE),)
+	echo "@/libbacktrace.a" >> $@
+endif
 	cat $< >> $@
 
-grt-install: libgrt.a grt.lst
+ifneq ($(GRT_LIBBACKTRACE),)
+$(GRT_LIBBACKTRACE): $(LIBBACKTRACE)
+	cp $< $@
+endif
+
+grt-install: libgrt.a $(GRT_LIBBACKTRACE) grt.lst
 	$(INSTALL_DATA) libgrt.a $(DESTDIR)$(grt_libdir)/libgrt.a
 	$(INSTALL_DATA) grt.lst $(DESTDIR)$(grt_libdir)/grt.lst
+ifneq ($(GRT_LIBBACKTRACE),)
+	$(INSTALL_DATA) $(GRT_LIBBACKTRACE) $(DESTDIR)$(grt_libdir)/libbacktrace.a
+endif
 
 grt-force:
 
diff --git a/src/grt/config/clock.c b/src/grt/config/clock.c
index 242af60..8f5d26f 100644
--- a/src/grt/config/clock.c
+++ b/src/grt/config/clock.c
@@ -34,8 +34,6 @@ grt_get_clk_tck (void)
 void
 grt_get_times (int *wall, int *user, int *sys)
 {
-  clock_t res;
-
   *wall = clock ();
   *user = 0;
   *sys = 0;
diff --git a/src/grt/config/jumps.c b/src/grt/config/jumps.c
index 00e17d3..2170943 100644
--- a/src/grt/config/jumps.c
+++ b/src/grt/config/jumps.c
@@ -81,10 +81,10 @@ static JMP_BUF run_env;
 #define NEED_SIGBUS_HANDLER
 #endif
 
-static struct sigaction prev_sigfpe_act;
+static struct sigaction prev_sigsegv_act;
 
 #ifdef NEED_SIGFPE_HANDLER
-static struct sigaction prev_sigsegv_act;
+static struct sigaction prev_sigfpe_act;
 #endif
 #ifdef NEED_SIGBUS_HANDLER
 static struct sigaction prev_sigbus_act;
@@ -105,15 +105,27 @@ get_bt_from_ucontext (void *uctxt, struct backtrace_addrs *bt)
 #endif
 
 #if defined (__linux__) && defined (__x86_64__)
-  ucontext *u = (ucontext *)uctxt;
+  ucontext_t *u = (ucontext_t *)uctxt;
   pc = (void *)u->uc_mcontext.gregs[REG_RIP];
 #endif
+#if defined (__linux__) && defined (__i386__)
+  ucontext_t *u = (ucontext_t *)uctxt;
+  pc = (void *)u->uc_mcontext.gregs[REG_EIP];
+#endif
 #if defined (__APPLE__) && defined (__i386__)
   ucontext_t *u = (ucontext_t *)uctxt;
   pc = (void *)u->uc_mcontext->__ss.__eip;
   bt->skip = 3;  /* This frame + sighandler + trampoline + marker - pc.  */
   bt->addrs[3] = pc;
+  return;
 #endif
+
+  for (i = 0; i < bt->size; i++)
+    if (bt->addrs[i] == pc)
+      {
+        bt->skip = i;
+        break;
+      }
 }
 
 /* Handler for SIGFPE signal.
diff --git a/src/grt/config/win32.c b/src/grt/config/win32.c
index 63d11a2..79935e6 100644
--- a/src/grt/config/win32.c
+++ b/src/grt/config/win32.c
@@ -25,6 +25,8 @@
 */
 
 #include <windows.h>
+#include <winbase.h>
+#include <dbghelp.h>
 #include <stdio.h>
 #include <setjmp.h>
 #include <assert.h>
@@ -47,19 +49,74 @@ struct exception_registration
   void *handler;
 };
 
+/* Save bactktrace from CTXT to BT, the first SKIP frames are skipped.
+   We need to use StackWalk64 as apparently CaptureStackBackTrace doesn't
+   work over JIT'ed code.  I suppose it checks whether PC belongs to the text
+   section of an image.  */
+
+static void
+get_bt_from_context (struct backtrace_addrs *bt, CONTEXT *ctxt, int skip)
+{
+  STACKFRAME64 frame;
+  unsigned mach;
+
+  bt->size = 0;
+  bt->skip = 0;
+  memset (&frame, 0, sizeof (frame));
+
+#ifdef __i386__
+  mach = IMAGE_FILE_MACHINE_I386;
+
+  frame.AddrPC.Offset = ctxt->Eip;
+  frame.AddrPC.Mode = AddrModeFlat;
+  frame.AddrFrame.Offset = ctxt->Ebp;
+  frame.AddrFrame.Mode = AddrModeFlat;
+  frame.AddrStack.Offset = ctxt->Esp;
+  frame.AddrStack.Mode = AddrModeFlat;
+
+#elif defined (__x86_64__)
+  mach = IMAGE_FILE_MACHINE_AMD64;
+
+  frame.AddrPC.Offset = ctxt->Rip;
+  frame.AddrPC.Mode = AddrModeFlat;
+  frame.AddrFrame.Offset = ctx->Rsp;
+  frame.AddrFrame.Mode = AddrModeFlat;
+  frame.AddrStack.Offset = ctx->Rsp;
+  frame.AddrStack.Mode = AddrModeFlat;
+
+#else
+#  warning "platform not supported"
+  return;
+#endif
+
+  while (bt->size < sizeof (bt->addrs) / sizeof (bt->addrs[0]))
+    {
+      if (skip > 0)
+	skip--;
+      else
+	bt->addrs[bt->size++] = (void *) frame.AddrPC.Offset;
+
+      if (!StackWalk64 (mach, GetCurrentProcess (), GetCurrentThread (),
+			&frame, ctxt, NULL, NULL, NULL, NULL))
+	break;
+    }
+}
+
 static EXCEPTION_DISPOSITION
 ghdl_SEH_handler (struct _EXCEPTION_RECORD* ExceptionRecord,
 		  void *EstablisherFrame,
 		  struct _CONTEXT* ContextRecord,
 		  void *DispatcherContext)
 {
+  struct backtrace_addrs bt;
   const char *msg = "";
 
   switch (ExceptionRecord->ExceptionCode)
     {
     case EXCEPTION_ACCESS_VIOLATION:
       /* Pc is ExceptionRecord->ExceptionAddress.  */
-      grt_null_access_error (NULL);
+      get_bt_from_context (&bt, ContextRecord, 1);
+      grt_null_access_error (&bt);
       break;
 
     case EXCEPTION_FLT_DENORMAL_OPERAND:
@@ -76,7 +133,8 @@ ghdl_SEH_handler (struct _EXCEPTION_RECORD* ExceptionRecord,
       break;
 
     case EXCEPTION_INT_OVERFLOW:
-      grt_overflow_error (NULL);
+      get_bt_from_context (&bt, ContextRecord, 1);
+      grt_overflow_error (&bt);
       break;
 
     case EXCEPTION_STACK_OVERFLOW:
@@ -134,7 +192,10 @@ __ghdl_run_through_longjump (int (*func)(void))
 void
 grt_save_backtrace (struct backtrace_addrs *bt, int skip)
 {
-  bt->size = 0;
+  CONTEXT ctxt;
+
+  RtlCaptureContext (&ctxt);
+  get_bt_from_context (bt, &ctxt, skip + 1);
 }
 
 #include <math.h>
@@ -165,4 +226,3 @@ void __gnat_raise_program_error(void)
    abort ();
 }
 #endif
-
diff --git a/src/grt/grt-backtraces-gcc.adb b/src/grt/grt-backtraces-gcc.adb
new file mode 100644
index 0000000..3ac412b
--- /dev/null
+++ b/src/grt/grt-backtraces-gcc.adb
@@ -0,0 +1,131 @@
+--  GHDL Run Time (GRT) - Symbolization using gcc libbacktrace.
+--  Copyright (C) 2015 Tristan Gingold
+--
+--  GHDL is free software; you can redistribute it and/or modify it under
+--  the terms of the GNU General Public License as published by the Free
+--  Software Foundation; either version 2, or (at your option) any later
+--  version.
+--
+--  GHDL is distributed in the hope that it will be useful, but WITHOUT ANY
+--  WARRANTY; without even the implied warranty of MERCHANTABILITY or
+--  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+--  for more details.
+--
+--  You should have received a copy of the GNU General Public License
+--  along with GCC; see the file COPYING.  If not, write to the Free
+--  Software Foundation, 59 Temple Place - Suite 330, Boston, MA
+--  02111-1307, USA.
+--
+--  As a special exception, if other files instantiate generics from this
+--  unit, or you link this unit with other files to produce an executable,
+--  this unit does not by itself cause the resulting executable to be
+--  covered by the GNU General Public License. This exception does not
+--  however invalidate any other reasons why the executable file might be
+--  covered by the GNU Public License.
+
+with System; use System;
+
+package body Grt.Backtraces.Gcc is
+   --  From backtrace.h
+   type Backtrace_Error_Callback is access procedure
+     (Data : System.Address; Msg : Address; Errnum : Integer);
+   pragma Convention (C, Backtrace_Error_Callback);
+
+   type Backtrace_State is null record;
+   pragma Convention (C, Backtrace_State);
+
+   type Backtrace_State_Acc is access all Backtrace_State;
+   pragma Convention (C, Backtrace_State_Acc);
+
+   function Backtrace_Create_State (Filename : Address;
+                                    Threaded : Integer;
+                                    Error_Callback : Backtrace_Error_Callback;
+                                    Data : System.Address)
+                                   return Backtrace_State_Acc;
+   pragma Import (C, Backtrace_Create_State);
+
+   type Backtrace_Full_Callback is access function
+     (Data : System.Address;
+      Pc : Address;
+      Filename : System.Address;
+      Lineno : Integer;
+      Function_Name : System.Address)
+     return Integer;
+   pragma Convention (C, Backtrace_Full_Callback);
+
+
+   function Backtrace_Pcinfo (State : Backtrace_State_Acc;
+                              Pc : Address;
+                              Callback : Backtrace_Full_Callback;
+                              Error_Callback : Backtrace_Error_Callback;
+                              Data : System.Address)
+                             return Integer;
+   pragma Import (C, Backtrace_Pcinfo);
+
+   State : Backtrace_State_Acc;
+   Initialized : Boolean := False;
+
+   Res_Filename : System.Address;
+   Res_Lineno : Natural;
+   Res_Subprg : System.Address;
+
+   procedure Error_Cb
+     (Data : Address; Msg : Address; Errnum : Integer);
+   pragma Convention (C, Error_Cb);
+
+   procedure Error_Cb
+     (Data : Address; Msg : Address; Errnum : Integer) is
+   begin
+      null;
+   end Error_Cb;
+
+   function Cb (Data : System.Address;
+                Pc : Address;
+                Filename : System.Address;
+                Lineno : Integer;
+                Function_Name : System.Address)
+               return Integer;
+   pragma Convention (C, Cb);
+
+   function Cb (Data : System.Address;
+                Pc : Address;
+                Filename : System.Address;
+                Lineno : Integer;
+                Function_Name : System.Address)
+               return Integer is
+   begin
+      if Res_Filename = Null_Address then
+         Res_Filename := Filename;
+         Res_Lineno := Lineno;
+         Res_Subprg := Function_Name;
+      end if;
+      return 0;
+   end Cb;
+
+   procedure Symbolizer (Pc : System.Address;
+                         Filename : out System.Address;
+                         Lineno : out Natural;
+                         Subprg : out System.Address)
+   is
+      Res : Integer;
+   begin
+      if not Initialized then
+         Initialized := True;
+         State := Backtrace_Create_State
+           (Null_Address, 0, Error_Cb'Access, Null_Address);
+      end if;
+
+      Res_Filename := Null_Address;
+      Res_Lineno := 0;
+      Res_Subprg := Null_Address;
+
+      if State /= null then
+         Res := Backtrace_Pcinfo
+           (State, Pc, Cb'access, Error_Cb'Access, Null_Address);
+      end if;
+
+      Filename := Res_Filename;
+      Lineno := Res_Lineno;
+      Subprg := Res_Subprg;
+   end Symbolizer;
+end Grt.Backtraces.Gcc;
diff --git a/src/grt/grt-backtraces-gcc.ads b/src/grt/grt-backtraces-gcc.ads
new file mode 100644
index 0000000..b5b35ff
--- /dev/null
+++ b/src/grt/grt-backtraces-gcc.ads
@@ -0,0 +1,35 @@
+--  GHDL Run Time (GRT) - Symbolization using gcc libbacktrace.
+--  Copyright (C) 2015 Tristan Gingold
+--
+--  GHDL is free software; you can redistribute it and/or modify it under
+--  the terms of the GNU General Public License as published by the Free
+--  Software Foundation; either version 2, or (at your option) any later
+--  version.
+--
+--  GHDL is distributed in the hope that it will be useful, but WITHOUT ANY
+--  WARRANTY; without even the implied warranty of MERCHANTABILITY or
+--  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+--  for more details.
+--
+--  You should have received a copy of the GNU General Public License
+--  along with GCC; see the file COPYING.  If not, write to the Free
+--  Software Foundation, 59 Temple Place - Suite 330, Boston, MA
+--  02111-1307, USA.
+--
+--  As a special exception, if other files instantiate generics from this
+--  unit, or you link this unit with other files to produce an executable,
+--  this unit does not by itself cause the resulting executable to be
+--  covered by the GNU General Public License. This exception does not
+--  however invalidate any other reasons why the executable file might be
+--  covered by the GNU Public License.
+
+with System;
+
+package Grt.Backtraces.Gcc is
+   pragma Preelaborate (Grt.Backtraces.Gcc);
+
+   procedure Symbolizer (Pc : System.Address;
+                         Filename : out System.Address;
+                         Lineno : out Natural;
+                         Subprg : out System.Address);
+end Grt.Backtraces.Gcc;
diff --git a/src/grt/grt-backtraces-jit.adb b/src/grt/grt-backtraces-jit.adb
new file mode 100644
index 0000000..dec546c
--- /dev/null
+++ b/src/grt/grt-backtraces-jit.adb
@@ -0,0 +1,42 @@
+--  GHDL Run Time (GRT) - Symbolization using jit interface.
+--  Copyright (C) 2015 Tristan Gingold
+--
+--  GHDL is free software; you can redistribute it and/or modify it under
+--  the terms of the GNU General Public License as published by the Free
+--  Software Foundation; either version 2, or (at your option) any later
+--  version.
+--
+--  GHDL is distributed in the hope that it will be useful, but WITHOUT ANY
+--  WARRANTY; without even the implied warranty of MERCHANTABILITY or
+--  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+--  for more details.
+--
+--  You should have received a copy of the GNU General Public License
+--  along with GCC; see the file COPYING.  If not, write to the Free
+--  Software Foundation, 59 Temple Place - Suite 330, Boston, MA
+--  02111-1307, USA.
+--
+--  As a special exception, if other files instantiate generics from this
+--  unit, or you link this unit with other files to produce an executable,
+--  this unit does not by itself cause the resulting executable to be
+--  covered by the GNU General Public License. This exception does not
+--  however invalidate any other reasons why the executable file might be
+--  covered by the GNU Public License.
+
+with System; use System;
+
+package body Grt.Backtraces.Jit is
+   procedure Symbolizer (Pc : System.Address;
+                         Filename : out Address;
+                         Lineno : out Natural;
+                         Subprg : out Address) is
+   begin
+      if Symbolizer_Proc = null then
+         Filename := Null_Address;
+         Lineno := 0;
+         Subprg := Null_Address;
+      else
+         Symbolizer_Proc.all (Pc, Filename, Lineno, Subprg);
+      end if;
+   end Symbolizer;
+end Grt.Backtraces.Jit;
diff --git a/src/grt/grt-backtraces-jit.ads b/src/grt/grt-backtraces-jit.ads
new file mode 100644
index 0000000..77afdfd
--- /dev/null
+++ b/src/grt/grt-backtraces-jit.ads
@@ -0,0 +1,44 @@
+--  GHDL Run Time (GRT) - Symbolization using jit interface.
+--  Copyright (C) 2015 Tristan Gingold
+--
+--  GHDL is free software; you can redistribute it and/or modify it under
+--  the terms of the GNU General Public License as published by the Free
+--  Software Foundation; either version 2, or (at your option) any later
+--  version.
+--
+--  GHDL is distributed in the hope that it will be useful, but WITHOUT ANY
+--  WARRANTY; without even the implied warranty of MERCHANTABILITY or
+--  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+--  for more details.
+--
+--  You should have received a copy of the GNU General Public License
+--  along with GCC; see the file COPYING.  If not, write to the Free
+--  Software Foundation, 59 Temple Place - Suite 330, Boston, MA
+--  02111-1307, USA.
+--
+--  As a special exception, if other files instantiate generics from this
+--  unit, or you link this unit with other files to produce an executable,
+--  this unit does not by itself cause the resulting executable to be
+--  covered by the GNU General Public License. This exception does not
+--  however invalidate any other reasons why the executable file might be
+--  covered by the GNU Public License.
+
+with System;
+
+package Grt.Backtraces.Jit is
+   pragma Preelaborate (Grt.Backtraces.Jit);
+
+   procedure Symbolizer (Pc : System.Address;
+                         Filename : out System.Address;
+                         Lineno : out Natural;
+                         Subprg : out System.Address);
+
+   --  In order to keep the package preelaborated, use an indirection.
+   type Symbolizer_Acc is access procedure (Pc : System.Address;
+                                            Filename : out System.Address;
+                                            Lineno : out Natural;
+                                            Subprg : out System.Address);
+
+   Symbolizer_Proc : Symbolizer_Acc;
+
+end Grt.Backtraces.Jit;
diff --git a/src/grt/grt-backtraces.adb b/src/grt/grt-backtraces.adb
index 8b779a7..d365ada 100644
--- a/src/grt/grt-backtraces.adb
+++ b/src/grt/grt-backtraces.adb
@@ -26,6 +26,7 @@
 with System;
 with Grt.Types; use Grt.Types;
 with Grt.Hooks; use Grt.Hooks;
+with Grt.Backtraces.Impl;
 
 package body Grt.Backtraces is
    --  If true, disp address in backtraces.
@@ -162,7 +163,6 @@ package body Grt.Backtraces is
    begin
       if Bt.Size = 0
         or else Bt.Skip >= Bt.Size
-        or else Symbolizer = null
       then
          --  No backtrace or no symbolizer.
          return;
@@ -170,15 +170,21 @@ package body Grt.Backtraces is
 
       Unknown := False;
       for I in Bt.Skip .. Bt.Size loop
-         Symbolizer.all (To_Address (Bt.Addrs (I)),
-                         Filename, Lineno, Subprg);
+         Backtraces.Impl.Symbolizer (To_Address (Bt.Addrs (I)),
+                                     Filename, Lineno, Subprg);
          if Subprg = Null_Address
            and (Filename = Null_Address or Lineno = 0)
          then
             Unknown := True;
+         elsif Subprg /= Null_Address
+           and then To_Ghdl_C_String (Subprg) (1 .. 5) = "grt__"
+         then
+            --  In the runtime.  Stop now.
+            exit;
          else
             if Unknown then
                Put_Err ("  from: [unknown caller]");
+               Newline_Err;
                Unknown := False;
             end if;
             Put_Err ("  from:");
diff --git a/src/grt/grt-backtraces.ads b/src/grt/grt-backtraces.ads
index 697b9dd..301131f 100644
--- a/src/grt/grt-backtraces.ads
+++ b/src/grt/grt-backtraces.ads
@@ -28,6 +28,7 @@ with Grt.Errors; use Grt.Errors;
 package Grt.Backtraces is
    pragma Preelaborate (Grt.Backtraces);
 
+   --  Display a backtrace on standard error, or nothing if not available.
    procedure Put_Err_Backtrace (Bt : Backtrace_Addrs);
 
    procedure Register;
diff --git a/src/grt/grt-errors.ads b/src/grt/grt-errors.ads
index cd7c3dc..25900da 100644
--- a/src/grt/grt-errors.ads
+++ b/src/grt/grt-errors.ads
@@ -22,7 +22,6 @@
 --  covered by the GNU General Public License. This exception does not
 --  however invalidate any other reasons why the executable file might be
 --  covered by the GNU Public License.
-with System;
 with Grt.Types; use Grt.Types;
 with Grt.Hooks;
 
@@ -78,13 +77,8 @@ package Grt.Errors is
 
    type Backtrace_Addrs_Acc is access Backtrace_Addrs;
 
-   type Symbolizer_Acc is access procedure (Pc : System.Address;
-                                            Filename : out System.Address;
-                                            Lineno : out Natural;
-                                            Subprg : out System.Address);
-
-   Symbolizer : Symbolizer_Acc := null;
-
+   --  Save the current backtrace to BT, but skip SKIP frame.  0 means that
+   --  the caller of this procedure will be in the backtrace.
    procedure Save_Backtrace (Bt : out Backtrace_Addrs; Skip : Natural);
    pragma Import (C, Save_Backtrace, "grt_save_backtrace");
 
diff --git a/src/ortho/mcode/binary_file-memory.adb b/src/ortho/mcode/binary_file-memory.adb
index 9797cd6..c9bb8ae 100644
--- a/src/ortho/mcode/binary_file-memory.adb
+++ b/src/ortho/mcode/binary_file-memory.adb
@@ -1,5 +1,5 @@
 --  Binary file execute in memory handler.
---  Copyright (C) 2006 Tristan Gingold
+--  Copyright (C) 2006 - 2015 Tristan Gingold
 --
 --  GHDL is free software; you can redistribute it and/or modify it under
 --  the terms of the GNU General Public License as published by the Free
@@ -95,10 +95,10 @@ package body Binary_File.Memory is
       end loop;
    end Write_Memory_Relocate;
 
-   function Get_Section_Base (Sect : Section_Acc) return System.Address is
+   function Get_Section_Addr (Sect : Section_Acc) return System.Address is
    begin
       return Sect.Data (0)'Address;
-   end Get_Section_Base;
+   end Get_Section_Addr;
 
    function Get_Section_Size (Sect : Section_Acc) return Pc_Type is
    begin
diff --git a/src/ortho/mcode/binary_file-memory.ads b/src/ortho/mcode/binary_file-memory.ads
index cc2b7e3..6775502 100644
--- a/src/ortho/mcode/binary_file-memory.ads
+++ b/src/ortho/mcode/binary_file-memory.ads
@@ -1,5 +1,5 @@
 --  Binary file execute in memory handler.
---  Copyright (C) 2006 Tristan Gingold
+--  Copyright (C) 2006-2015 Tristan Gingold
 --
 --  GHDL is free software; you can redistribute it and/or modify it under
 --  the terms of the GNU General Public License as published by the Free
@@ -21,13 +21,18 @@ package Binary_File.Memory is
 
    --  Must be called before set_symbol_address.
    procedure Write_Memory_Init;
+
+   --  Give a value to an undefined or external symbol.
    procedure Set_Symbol_Address (Sym : Symbol; Addr : System.Address);
 
+   --  Do the real work: resolve relocations.
    procedure Write_Memory_Relocate (Error : out Boolean);
 
-   function Get_Section_Base (Sect : Section_Acc) return System.Address;
+   --  Read the result: get address and size of a section.
+   function Get_Section_Addr (Sect : Section_Acc) return System.Address;
    function Get_Section_Size (Sect : Section_Acc) return Pc_Type;
 
+   --  Helpers.
    function To_Pc_Type is new Ada.Unchecked_Conversion
      (Source => System.Address, Target => Pc_Type);
    function To_Address is new Ada.Unchecked_Conversion
diff --git a/src/ortho/mcode/ortho_jit.adb b/src/ortho/mcode/ortho_jit.adb
index f01c8fa..6f4fa37 100644
--- a/src/ortho/mcode/ortho_jit.adb
+++ b/src/ortho/mcode/ortho_jit.adb
@@ -120,6 +120,7 @@ package body Ortho_Jit is
       use Ada.Text_IO;
    begin
       Put_Line (" -g             Generate debugging informations");
+      Put_Line (" -g0            Do not generate any debugging informations");
       Put_Line (" --debug-be=X   Set X internal debugging flags");
       Put_Line (" --snap=FILE    Write memory snapshot to FILE");
    end Disp_Help;
@@ -145,7 +146,7 @@ package body Ortho_Jit is
          if Sect = null then
             return (Null_Address, 0);
          else
-            Addr := Get_Section_Base (Sect);
+            Addr := Get_Section_Addr (Sect);
             Size := Get_Section_Size (Sect);
             return (Addr, Storage_Offset (Size));
          end if;
diff --git a/src/ortho/ortho_jit.ads b/src/ortho/ortho_jit.ads
index 76a3f29..a47cdc9 100644
--- a/src/ortho/ortho_jit.ads
+++ b/src/ortho/ortho_jit.ads
@@ -40,6 +40,9 @@ package Ortho_Jit is
    --  Return the name of the code generator, to be displayed by --version.
    function Get_Jit_Name return String;
 
+   --  Symbolizer: convert PC to a filename (a NUL terminated string), line
+   --  number and subprogram name (NUL terminated).
+   --  Unresolved values are Null_Address and 0.
    procedure Symbolize (Pc : Address;
                         Filename : out Address;
                         Lineno : out Natural;