[Guile-commits] GNU Guile branch, master, updated. release_1-9-12-94-g99765ed

[Ludovic Courtès]

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- Log -----------------------------------------------------------------
commit 99765ed17245b7c54789c01702806bf27b161cb7
Author: Ludovic Courtès <address@hidden>
Date:   Mon Sep 27 01:28:49 2010 +0200

    Remove `scm_t_aligned_cell'.
    
    * libguile/_scm.h (scm_aligned_cell, scm_t_aligned_cell): Remove.  The
      whole approach was misguided as the compiler can't guarantee absolute
      alignment on the stack.

commit 8e4c60ff2902363b41f4c23e686ad65c17e90196
Author: Ludovic Courtès <address@hidden>
Date:   Sun Sep 26 16:24:35 2010 +0200

    Fix argument passing in VM hooks.
    
    * libguile/vm.c (vm_dispatch_hook): Take care of FRAME's alignment
      explicitly so that it's correct even if the current stack frame isn't
      8-byte aligned (as can be the case on i686--the SysV i386 ABI just
      says that the stack is word-aligned.)

commit 8684029d210be37775e32f7f4b4ca499bb1f1c56
Author: Ludovic Courtès <address@hidden>
Date:   Sun Sep 26 16:23:53 2010 +0200

    Have address@hidden' honor VM changes by winds.
    
    * libguile/control.c (scm_c_abort): Update VM after the `scm_dowinds'
      call.
    
    * test-suite/tests/control.test ("the-vm"): New test prefix.

-----------------------------------------------------------------------

Summary of changes:
 libguile/_scm.h               |   30 ------------------------------
 libguile/control.c            |    6 +++++-
 libguile/vm.c                 |   13 +++++++++----
 test-suite/tests/control.test |   26 ++++++++++++++++++++++++++
 4 files changed, 40 insertions(+), 35 deletions(-)

diff --git a/libguile/_scm.h b/libguile/_scm.h
index b04752c..0d86fe1 100644
--- a/libguile/_scm.h
+++ b/libguile/_scm.h
@@ -197,36 +197,6 @@
 #define SCM_OBJCODE_COOKIE                              \
   "GOOF-" SCM_OBJCODE_MACHINE_VERSION_STRING "---"
 
-
-/* Cells have to be 8-byte aligned.  Use `scm_t_aligned_cell' when not
-   allocating on the heap to have this guarantee.  This is similar to the
-   `SCM_ALIGNED' macro but provides an option likely to work with compilers
-   other than GCC.  */
-
-#ifdef __GNUC__
-
-struct scm_aligned_cell
-{
-  scm_t_cell cell __attribute__ ((__aligned__ (8)));
-};
-
-typedef struct scm_aligned_cell scm_t_aligned_cell;
-
-#else /* !__GNUC__ */
-
-union scm_aligned_cell
-{
-  double alignment;
-  scm_t_cell cell;
-};
-
-typedef union scm_aligned_cell scm_t_aligned_cell;
-
-#endif /* !__GNUC__ */
-
-/* Make sure we get the right alignment.  */
-verify (alignof (scm_t_aligned_cell) >= 8);
-
 #endif  /* SCM__SCM_H */
 
 /*
diff --git a/libguile/control.c b/libguile/control.c
index 99bc846..a696895 100644
--- a/libguile/control.c
+++ b/libguile/control.c
@@ -211,10 +211,14 @@ scm_c_abort (SCM vm, SCM tag, size_t n, SCM *argv, 
scm_t_int64 cookie)
 
   /* Unwind once more, beyond the prompt. */
   winds = SCM_CDR (winds), delta++;
-  
+
   /* Unwind */
   scm_dowinds (winds, delta);
 
+  /* Unwinding may have changed the current thread's VM, so use the
+     new one.  */
+  vm = scm_the_vm ();
+
   /* Restore VM regs */
   SCM_VM_DATA (vm)->fp = SCM_PROMPT_REGISTERS (prompt)->fp;
   SCM_VM_DATA (vm)->sp = SCM_PROMPT_REGISTERS (prompt)->sp;
diff --git a/libguile/vm.c b/libguile/vm.c
index 7512d10..17ad96d 100644
--- a/libguile/vm.c
+++ b/libguile/vm.c
@@ -191,7 +191,7 @@ vm_dispatch_hook (SCM vm, int hook_num)
   struct scm_vm *vp;
   SCM hook;
   struct scm_frame c_frame;
-  scm_t_aligned_cell frame;
+  scm_t_cell *frame;
   SCM args[1];
   int saved_trace_level;
 
@@ -218,9 +218,14 @@ vm_dispatch_hook (SCM vm, int hook_num)
   c_frame.sp = vp->sp;
   c_frame.ip = vp->ip;
   c_frame.offset = 0;
-  frame.cell.word_0 = SCM_PACK (scm_tc7_frame);
-  frame.cell.word_1 = PTR2SCM (&c_frame);
-  args[0] = PTR2SCM (&frame);
+
+  /* Arrange for FRAME to be 8-byte aligned, like any other cell.  */
+  frame = alloca (sizeof (*frame) + 8);
+  frame = (scm_t_cell *) ROUND_UP ((scm_t_uintptr) frame, 8UL);
+
+  frame->word_0 = SCM_PACK (scm_tc7_frame);
+  frame->word_1 = PTR2SCM (&c_frame);
+  args[0] = PTR2SCM (frame);
 
   scm_c_run_hookn (hook, args, 1);
 
diff --git a/test-suite/tests/control.test b/test-suite/tests/control.test
index b3ab707..a4173ff 100644
--- a/test-suite/tests/control.test
+++ b/test-suite/tests/control.test
@@ -19,6 +19,7 @@
 
 (define-module (test-suite test-control)
   #:use-module (ice-9 control)
+  #:use-module (system vm vm)
   #:use-module (srfi srfi-11)
   #:use-module (test-suite lib))
 
@@ -225,3 +226,28 @@
 (with-test-prefix "abort to unknown prompt"
   (pass-if-exception "foo" '(misc-error . "^Abort to unknown prompt")
                      (abort-to-prompt 'does-not-exist)))
+
+(with-test-prefix "the-vm"
+
+  (pass-if "unwind changes VMs"
+    (let ((new-vm  (make-vm))
+          (prev-vm (the-vm))
+          (proc    (lambda (x y)
+                     (expt x y)))
+          (call    (lambda (p x y)
+                     (p x y))))
+      (catch 'foo
+        (lambda ()
+          (dynamic-wind
+            (lambda ()
+              (set-thread-vm! (current-thread) new-vm))
+            (lambda ()
+              (vm-apply new-vm
+                        (lambda () (throw 'foo (the-vm)))
+                        '()))
+            (lambda ()
+              (set-thread-vm! (current-thread) prev-vm))))
+        (lambda (key vm)
+          (and (eq? key 'foo)
+               (eq? vm new-vm)
+               (eq? (the-vm) prev-vm)))))))


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