[Sbcl-commits] CVS: sbcl/src/runtime x86-arch.c,1.39,1.40 bsd-os.h,1.17,1.18 x86-64-arch.c,1.11,1.12

[Juho S. <js...@us...>]

Update of /cvsroot/sbcl/sbcl/src/runtime
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv11561/src/runtime

Modified Files:
	x86-arch.c bsd-os.h x86-64-arch.c 
Log Message:
0.9.11.23:
        Oops. Realize why the single-stepping code deleted in .20 was actually
        necessary after all. Restore most of it, add a test, and fix the
        original problem (extra trace traps on Solaris) by munging the
        processor's single-step flag in a different way.


Index: x86-arch.c
===================================================================
RCS file: /cvsroot/sbcl/sbcl/src/runtime/x86-arch.c,v
retrieving revision 1.39
retrieving revision 1.40
diff -u -d -r1.39 -r1.40
--- x86-arch.c	7 Apr 2006 12:49:59 -0000	1.39
+++ x86-arch.c	7 Apr 2006 16:33:13 -0000	1.40
@@ -169,6 +169,14 @@
     *((char *)pc + 1) = (orig_inst & 0xff00) >> 8;
 }
 
+/* When single stepping, single_stepping holds the original instruction
+ * PC location. */
+unsigned int *single_stepping = NULL;
+#ifdef CANNOT_GET_TO_SINGLE_STEP_FLAG
+unsigned int  single_step_save1;
+unsigned int  single_step_save2;
+unsigned int  single_step_save3;
+#endif
 
 void
 arch_do_displaced_inst(os_context_t *context, unsigned int orig_inst)
@@ -178,24 +186,86 @@
     /* Put the original instruction back. */
     *((char *)pc) = orig_inst & 0xff;
     *((char *)pc + 1) = (orig_inst & 0xff00) >> 8;
+
+#ifdef CANNOT_GET_TO_SINGLE_STEP_FLAG
+    /* Install helper instructions for the single step:
+     * pushf; or [esp],0x100; popf. */
+    single_step_save1 = *(pc-3);
+    single_step_save2 = *(pc-2);
+    single_step_save3 = *(pc-1);
+    *(pc-3) = 0x9c909090;
+    *(pc-2) = 0x00240c81;
+    *(pc-1) = 0x9d000001;
+#else
+    *context_eflags_addr(context) |= 0x100;
+#endif
+
+    single_stepping = pc;
+
+#ifdef CANNOT_GET_TO_SINGLE_STEP_FLAG
+    *os_context_pc_addr(context) = (char *)pc - 9;
+#endif
 }
 
-
 void
 sigtrap_handler(int signal, siginfo_t *info, void *void_context)
 {
     os_context_t *context = (os_context_t*)void_context;
     unsigned int trap;
 
+#ifndef LISP_FEATURE_WIN32
+    if (single_stepping && (signal==SIGTRAP))
+    {
+        /* fprintf(stderr,"* single step trap %x\n", single_stepping); */
+
+#ifdef CANNOT_GET_TO_SINGLE_STEP_FLAG
+        /* Un-install single step helper instructions. */
+        *(single_stepping-3) = single_step_save1;
+        *(single_stepping-2) = single_step_save2;
+        *(single_stepping-1) = single_step_save3;
+#else
+        *context_eflags_addr(context) &= ~0x100;
+#endif
+        /* Re-install the breakpoint if possible. */
+        if (*os_context_pc_addr(context) == (int)single_stepping + 1) {
+            fprintf(stderr, "warning: couldn't reinstall breakpoint\n");
+        } else {
+            *((char *)single_stepping) = BREAKPOINT_INST;       /* x86 INT3 */
+            *((char *)single_stepping+1) = trap_Breakpoint;
+        }
+
+        single_stepping = NULL;
+        return;
+    }
+#endif
+
     /* This is just for info in case the monitor wants to print an
      * approximation. */
     current_control_stack_pointer =
         (lispobj *)*os_context_sp_addr(context);
 
+    /* FIXME: CMUCL puts the float control restoration code here.
+       Thus, it seems to me that single-stepping won't restore the
+       float control.  Since SBCL currently doesn't support
+       single-stepping (as far as I can tell) this is somewhat moot,
+       but it might be worth either moving this code up or deleting
+       the single-stepping code entirely.  -- CSR, 2002-07-15 */
 #ifdef LISP_FEATURE_LINUX
     os_restore_fp_control(context);
 #endif
 
+
+#ifdef LISP_FEATURE_SUNOS
+    /* For some reason the breakpoints that :ENCAPSULATE NIL tracing sets up
+     * cause a trace trap (i.e. processor single-stepping trap) on the following
+     * instruction on Solaris 10/x86. -- JES, 2006-04-07
+     */
+    if (info->si_code == TRAP_TRACE) {
+        lose("foo");
+        return;
+    }
+#endif
+
     /* On entry %eip points just after the INT3 byte and aims at the
      * 'kind' value (eg trap_Cerror). For error-trap and Cerror-trap a
      * number of bytes will follow, the first is the length of the byte

Index: bsd-os.h
===================================================================
RCS file: /cvsroot/sbcl/sbcl/src/runtime/bsd-os.h,v
retrieving revision 1.17
retrieving revision 1.18
diff -u -d -r1.17 -r1.18
--- bsd-os.h	7 Apr 2006 12:49:59 -0000	1.17
+++ bsd-os.h	7 Apr 2006 16:33:13 -0000	1.18
@@ -49,6 +49,11 @@
 
 #include <sys/ucontext.h>
 typedef ucontext_t os_context_t;
+/* As the sbcl-devel message from Raymond Wiker 2000-12-01, FreeBSD
+ * (unlike Linux and OpenBSD) doesn't let us tweak the CPU's single
+ * step flag bit by messing with the flags stored in a signal context,
+ * so we need to implement single stepping in a more roundabout way. */
+#define CANNOT_GET_TO_SINGLE_STEP_FLAG
 #define SIG_MEMORY_FAULT SIGSEGV
 /* Sometime in late 2005 FreeBSD was changed to signal SIGSEGV instead
  * of SIGBUS for memory faults, as required by POSIX. In order to

Index: x86-64-arch.c
===================================================================
RCS file: /cvsroot/sbcl/sbcl/src/runtime/x86-64-arch.c,v
retrieving revision 1.11
retrieving revision 1.12
diff -u -d -r1.11 -r1.12
--- x86-64-arch.c	7 Apr 2006 12:49:59 -0000	1.11
+++ x86-64-arch.c	7 Apr 2006 16:33:13 -0000	1.12
@@ -162,6 +162,9 @@
     *((char *)pc + 1) = (orig_inst & 0xff00) >> 8;
 }
 
+/* When single stepping, single_stepping holds the original instruction
+ * PC location. */
+unsigned int *single_stepping = NULL;
 
 void
 arch_do_displaced_inst(os_context_t *context, unsigned int orig_inst)
@@ -171,7 +174,12 @@
     /* Put the original instruction back. */
     *((char *)pc) = orig_inst & 0xff;
     *((char *)pc + 1) = (orig_inst & 0xff00) >> 8;
+
+    *context_eflags_addr(context) |= 0x100;
+
+    single_stepping = pc;
 }
+
 
 void
 sigtrap_handler(int signal, siginfo_t *info, void *void_context)
@@ -180,11 +188,33 @@
     os_context_t *context = (os_context_t*)void_context;
     unsigned int trap;
 
+    if (single_stepping && (signal==SIGTRAP))
+    {
+        *context_eflags_addr(context) ^= 0x100;
+
+        /* Re-install the breakpoint if possible. */
+        if (*os_context_pc_addr(context) == (int)single_stepping + 1) {
+            fprintf(stderr, "warning: couldn't reinstall breakpoint\n");
+        } else {
+            *((char *)single_stepping) = BREAKPOINT_INST;       /* x86 INT3 */
+            *((char *)single_stepping+1) = trap_Breakpoint;
+        }
+
+        single_stepping = NULL;
+        return;
+    }
+
     /* This is just for info in case the monitor wants to print an
      * approximation. */
     current_control_stack_pointer =
         (lispobj *)*os_context_sp_addr(context);
 
+    /* FIXME: CMUCL puts the float control restoration code here.
+       Thus, it seems to me that single-stepping won't restore the
+       float control.  Since SBCL currently doesn't support
+       single-stepping (as far as I can tell) this is somewhat moot,
+       but it might be worth either moving this code up or deleting
+       the single-stepping code entirely.  -- CSR, 2002-07-15 */
 #ifdef LISP_FEATURE_LINUX
     os_restore_fp_control(context);
 #endif