[PATCH] avoid redundant zero-ing in proc/env alloc

[Eric Wong <e@80x24.org>]

* proc.c (rb_proc_alloc): do not zero memory,
  callers must be careful not to trigger GC before filling out
  rb_proc_t

* proc.c (proc_dup): initialize proc->is_from_method

* vm.c (vm_make_env_each): inline env_alloc to simplify reading.
  We must be careful about invoking GC while rb_env_t is
  uninitialized.

* vm.c (env_alloc): remove

* vm.c (rb_vm_make_proc): initialize proc->{is_from_method,is_lambda}
---
 proc.c |  5 +++--
 vm.c   | 32 ++++++++++++++++----------------
 2 files changed, 19 insertions(+), 18 deletions(-)

diff --git a/proc.c b/proc.c
index 63e2319..c793c01 100644
--- a/proc.c
+++ b/proc.c
@@ -86,8 +86,8 @@ static const rb_data_type_t proc_data_type = {
 VALUE
 rb_proc_alloc(VALUE klass)
 {
-    rb_proc_t *proc;
-    return TypedData_Make_Struct(klass, rb_proc_t, &proc_data_type, proc);
+    rb_proc_t *proc = ALLOC(rb_proc_t);
+    return TypedData_Wrap_Struct(klass, &proc_data_type, proc);
 }
 
 VALUE
@@ -115,6 +115,7 @@ proc_dup(VALUE self)
     dst->blockprocval = src->blockprocval;
     dst->envval = src->envval;
     dst->safe_level = src->safe_level;
+    dst->is_from_method = 0;
     dst->is_lambda = src->is_lambda;
 
     return procval;
diff --git a/vm.c b/vm.c
index 7738220..0a4adc5 100644
--- a/vm.c
+++ b/vm.c
@@ -404,18 +404,6 @@ static const rb_data_type_t env_data_type = {
     NULL, NULL, RUBY_TYPED_FREE_IMMEDIATELY
 };
 
-static VALUE
-env_alloc(int local_size)
-{
-    rb_env_t *env;
-
-    env = xcalloc(1, sizeof(rb_env_t) + ((local_size + 1) * sizeof(VALUE)));
-    env->env_size = local_size + 1 + 1;
-    env->local_size = local_size;
-
-    return TypedData_Wrap_Struct(rb_cEnv, &env_data_type, env);
-}
-
 static VALUE check_env_value(VALUE envval);
 
 static int
@@ -488,10 +476,9 @@ vm_make_env_each(const rb_thread_t *const th, rb_control_frame_t *const cfp,
     }
 
     /* allocate env */
-    envval = env_alloc(local_size);
-    GetEnvPtr(envval, env);
-
-    env->prev_envval = penvval;
+    env = xmalloc(sizeof(rb_env_t) + ((local_size + 1) * sizeof(VALUE)));
+    env->env_size = local_size + 1 + 1;
+    env->local_size = local_size;
 
     for (i = 0; i <= local_size; i++) {
 	env->env[i] = envptr[-local_size + i];
@@ -504,6 +491,15 @@ vm_make_env_each(const rb_thread_t *const th, rb_control_frame_t *const cfp,
 #endif
     }
 
+    /* be careful not to trigger GC after this */
+    envval = TypedData_Wrap_Struct(rb_cEnv, &env_data_type, env);
+
+   /*
+    * must happen after TypedData_Wrap_Struct to ensure penvval is markable
+    * in case object allocation triggers GC and clobbers penvval.
+    */
+    env->prev_envval = penvval;
+
     *envptr = envval;		/* GC mark */
     nenvptr = &env->env[i - 1];
     nenvptr[1] = envval;	/* frame self */
@@ -513,8 +509,10 @@ vm_make_env_each(const rb_thread_t *const th, rb_control_frame_t *const cfp,
 
     /* as Binding */
     env->block.self = cfp->self;
+    env->block.klass = 0;
     env->block.ep = cfp->ep;
     env->block.iseq = cfp->iseq;
+    env->block.proc = 0;
 
     if (!RUBY_VM_NORMAL_ISEQ_P(cfp->iseq)) {
 	/* TODO */
@@ -679,6 +677,8 @@ rb_vm_make_proc(rb_thread_t *th, const rb_block_t *block, VALUE klass)
     proc->block.proc = procval;
     proc->envval = envval;
     proc->safe_level = th->safe_level;
+    proc->is_from_method = 0;
+    proc->is_lambda = 0;
 
     if (VMDEBUG) {
 	if (th->stack < block->ep && block->ep < th->stack + th->stack_size) {
-- 
EW