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Bug #9609

[PATCH] vm_eval.c: fix misplaced RB_GC_GUARDs

Added by normalperson (Eric Wong) about 6 years ago. Updated about 2 years ago.

Status:
Rejected
Priority:
Normal
Target version:
-
ruby -v:
-
Backport:
[ruby-core:61359]

Description

RB_GC_GUARD needs to be placed after RARRAY_PTR usages to portably
prevent compilers from optimizing the VALUE away.


Files

0001-vm_eval.c-fix-misplaced-GC-guard.patch (1.46 KB) 0001-vm_eval.c-fix-misplaced-GC-guard.patch normalperson (Eric Wong), 03/07/2014 10:06 AM

Updated by ko1 (Koichi Sasada) about 6 years ago

  • ruby -v changed from ruby 2.2.0dev (2014-03-07 trunk 45281) [x86_64-linux] to -

(2014/03/07 19:09), normalperson@yhbt.net wrote:

RB_GC_GUARD needs to be placed after RARRAY_PTR usages to portably
prevent compilers from optimizing the VALUE away.

And also it should be RARRAY_CONST_PTR().

--
// SASADA Koichi at atdot dot net

Updated by normalperson (Eric Wong) about 6 years ago

SASADA Koichi ko1@atdot.net wrote:

And also it should be RARRAY_CONST_PTR().

Thanks (r45283). Btw, I noticed rb_apply uses RARRAY_PTR, too,
but also with OBJ_FREEZE.

Should we ignore WB unprotect for frozen objects?

Updated by ko1 (Koichi Sasada) about 6 years ago

(2014/03/07 19:38), Eric Wong wrote:

Thanks (r45283). Btw, I noticed rb_apply uses RARRAY_PTR, too,
but also with OBJ_FREEZE.

Should we ignore WB unprotect for frozen objects?

No relation between frozen and wb unprotected flag. We can use
RARRAY_CONST_PTR() for this case. I'll commit it with other patches.

Index: enum.c
===================================================================
--- enum.c  (revision 45283)
+++ enum.c  (working copy)
@@ -1163,7 +1163,7 @@ static void
 nmin_filter(struct nmin_data *data)
 {
     long n;
-    VALUE *beg;
+    const VALUE *beg;
     int eltsize;
     long numelts;

@@ -1175,7 +1175,7 @@ nmin_filter(struct nmin_data *data)
    return;

     n = data->n;
-    beg = RARRAY_PTR(data->buf);
+    beg = RARRAY_CONST_PTR(data->buf);
     eltsize = data->by ? 2 : 1;
     numelts = data->curlen;

Index: enumerator.c
===================================================================
--- enumerator.c    (revision 45283)
+++ enumerator.c    (working copy)
@@ -422,13 +422,13 @@ static VALUE
 enumerator_block_call(VALUE obj, rb_block_call_func *func, VALUE arg)
 {
     int argc = 0;
-    VALUE *argv = 0;
+    const VALUE *argv = 0;
     const struct enumerator *e = enumerator_ptr(obj);
     ID meth = e->meth;

     if (e->args) {
    argc = RARRAY_LENINT(e->args);
-   argv = RARRAY_PTR(e->args);
+   argv = RARRAY_CONST_PTR(e->args);
     }
     return rb_block_call(e->obj, meth, argc, argv, func, arg);
 }
Index: internal.h
===================================================================
--- internal.h  (revision 45283)
+++ internal.h  (working copy)
@@ -963,9 +963,9 @@ VALUE rb_int_positive_pow(long x, unsign
 /* process.c */
 int rb_exec_async_signal_safe(const struct rb_execarg *e, char *errmsg, size_t errmsg_buflen);
 rb_pid_t rb_fork_async_signal_safe(int *status, int (*chfunc)(void*, char *, size_t), void *charg, VALUE fds, char *errmsg, size_t errmsg_buflen);
-VALUE rb_execarg_new(int argc, VALUE *argv, int accept_shell);
+VALUE rb_execarg_new(int argc, const VALUE *argv, int accept_shell);
 struct rb_execarg *rb_execarg_get(VALUE execarg_obj); /* dangerous. needs GC guard. */
-VALUE rb_execarg_init(int argc, VALUE *argv, int accept_shell, VALUE execarg_obj);
+VALUE rb_execarg_init(int argc, const VALUE *argv, int accept_shell, VALUE execarg_obj);
 int rb_execarg_addopt(VALUE execarg_obj, VALUE key, VALUE val);
 void rb_execarg_fixup(VALUE execarg_obj);
 int rb_execarg_run_options(const struct rb_execarg *e, struct rb_execarg *s, char* errmsg, size_t errmsg_buflen);
Index: io.c
===================================================================
--- io.c    (revision 45283)
+++ io.c    (working copy)
@@ -6227,7 +6227,7 @@ rb_io_s_popen(int argc, VALUE *argv, VAL
 #endif
    tmp = rb_ary_dup(tmp);
    RBASIC_CLEAR_CLASS(tmp);
-   execarg_obj = rb_execarg_new((int)len, RARRAY_PTR(tmp), FALSE);
+   execarg_obj = rb_execarg_new((int)len, RARRAY_CONST_PTR(tmp), FALSE);
    rb_ary_clear(tmp);
     }
     else {
Index: numeric.c
===================================================================
--- numeric.c   (revision 45283)
+++ numeric.c   (working copy)
@@ -1887,7 +1887,7 @@ num_step_size(VALUE from, VALUE args, VA
     VALUE to, step, hash;
     int desc;
     int argc = args ? RARRAY_LENINT(args) : 0;
-    VALUE *argv = args ? RARRAY_PTR(args) : 0;
+    const VALUE *argv = args ? RARRAY_CONST_PTR(args) : 0;

     NUM_STEP_SCAN_ARGS(argc, argv, to, step, hash, desc);

Index: process.c
===================================================================
--- process.c   (revision 45283)
+++ process.c   (working copy)
@@ -2167,7 +2167,7 @@ rb_exec_fillarg(VALUE prog, int argc, VA
 }

 VALUE
-rb_execarg_new(int argc, VALUE *argv, int accept_shell)
+rb_execarg_new(int argc, const VALUE *argv, int accept_shell)
 {
     VALUE execarg_obj;
     struct rb_execarg *eargp;
@@ -2186,7 +2186,7 @@ rb_execarg_get(VALUE execarg_obj)
 }

 VALUE
-rb_execarg_init(int argc, VALUE *argv, int accept_shell, VALUE execarg_obj)
+rb_execarg_init(int argc, const VALUE *argv, int accept_shell, VALUE execarg_obj)
 {
     struct rb_execarg *eargp = rb_execarg_get(execarg_obj);
     VALUE prog, ret;
Index: vm_eval.c
===================================================================
--- vm_eval.c   (revision 45283)
+++ vm_eval.c   (working copy)
@@ -751,7 +751,7 @@ rb_apply(VALUE recv, ID mid, VALUE args)
    args = rb_ary_subseq(args, 0, argc);
    RBASIC_CLEAR_CLASS(args);
    OBJ_FREEZE(args);
-   ret = rb_call(recv, mid, argc, RARRAY_PTR(args), CALL_FCALL);
+   ret = rb_call(recv, mid, argc, RARRAY_CONST_PTR(args), CALL_FCALL);
    RB_GC_GUARD(args);
    return ret;
     }
@@ -1482,7 +1482,7 @@ rb_eval_cmd(VALUE cmd, VALUE arg, int le
    rb_set_safe_level_force(level);
    if ((state = EXEC_TAG()) == 0) {
        val = rb_funcall2(cmd, rb_intern("call"), RARRAY_LENINT(arg),
-                 RARRAY_PTR(arg));
+                 RARRAY_CONST_PTR(arg));
    }
    POP_TAG();


// SASADA Koichi at atdot dot net

Updated by ko1 (Koichi Sasada) about 6 years ago

(2014/03/07 20:03), SASADA Koichi wrote:

Should we ignore WB unprotect for frozen objects?
No relation between frozen and wb unprotected flag. We can use
RARRAY_CONST_PTR() for this case. I'll commit it with other patches.

Ah, I understand what you mean. As you say, we can ignore unprotect.
But I think the checking cost is bigger.

--
// SASADA Koichi at atdot dot net

#5

Updated by normalperson (Eric Wong) about 2 years ago

  • Backport deleted (1.9.3: REQUIRED, 2.0.0: REQUIRED, 2.1: REQUIRED)
  • Status changed from Open to Rejected

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