Reviewers: fschneider,
Message:
PTAL.
Description:
Tune context allocation for variables accessed from inner scopes.
After introduction of with scopes we have enough static information to omit
context allocation in the case that a variable is accessed from a nested
block
or catch scope of the same function. Only variables accessed from the
inside of
a nested function or with scope are forced to be allocated in the context.
This essentially reverts
http://code.google.com/p/v8/source/detail?r=9281 .
which in turn reverted an earlier change.
Please review this at http://codereview.chromium.org/8431001/
SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files:
M src/scopes.cc
M src/variables.h
M src/variables.cc
Index: src/scopes.cc
diff --git a/src/scopes.cc b/src/scopes.cc
index
3167c4d0926f916dbe443dc5c3019e79ca74399b..78233d5a3f4430a33753a9abb6d7b0f76dc9fee5
100644
--- a/src/scopes.cc
+++ b/src/scopes.cc
@@ -707,9 +707,9 @@ static void PrintVar(int indent, Variable* var) {
PrintName(var->name());
PrintF("; // ");
PrintLocation(var);
- if (var->is_accessed_from_inner_scope()) {
+ if (var->has_forced_context_allocation()) {
if (!var->IsUnallocated()) PrintF(", ");
- PrintF("inner scope access");
+ PrintF("forced context allocation");
}
PrintF("\n");
}
@@ -848,7 +848,9 @@ Variable* Scope::LookupRecursive(Handle<String> name,
*binding_kind = BOUND;
} else if (outer_scope_ != NULL) {
var = outer_scope_->LookupRecursive(name, context, binding_kind);
- if (*binding_kind == BOUND) var->MarkAsAccessedFromInnerScope();
+ if (*binding_kind == BOUND && (is_function_scope() ||
is_with_scope())) {
+ var->ForceContextAllocation();
+ }
}
if (is_with_scope()) {
@@ -980,7 +982,7 @@ bool Scope::MustAllocate(Variable* var) {
// via an eval() call. This is only possible if the variable has a
// visible name.
if ((var->is_this() || var->name()->length() > 0) &&
- (var->is_accessed_from_inner_scope() ||
+ (var->has_forced_context_allocation() ||
scope_calls_eval_ ||
inner_scope_calls_eval_ ||
scope_contains_with_ ||
@@ -1003,7 +1005,7 @@ bool Scope::MustAllocateInContext(Variable* var) {
// catch-bound variables are always allocated in a context.
if (var->mode() == TEMPORARY) return false;
if (is_catch_scope() || is_block_scope()) return true;
- return var->is_accessed_from_inner_scope() ||
+ return var->has_forced_context_allocation() ||
scope_calls_eval_ ||
inner_scope_calls_eval_ ||
scope_contains_with_ ||
@@ -1067,9 +1069,8 @@ void Scope::AllocateParameterLocals() {
Variable* var = params_[i];
ASSERT(var->scope() == this);
if (uses_nonstrict_arguments) {
- // Give the parameter a use from an inner scope, to force allocation
- // to the context.
- var->MarkAsAccessedFromInnerScope();
+ // Force context allocation of the parameter.
+ var->ForceContextAllocation();
}
if (MustAllocate(var)) {
Index: src/variables.cc
diff --git a/src/variables.cc b/src/variables.cc
index
d85e1b270ab30d452a3db4f84811a73458521c3b..d6129b1e43e1a4357b78fa15d37b184a46a238f1
100644
--- a/src/variables.cc
+++ b/src/variables.cc
@@ -67,7 +67,7 @@ Variable::Variable(Scope* scope,
index_(-1),
local_if_not_shadowed_(NULL),
is_valid_LHS_(is_valid_LHS),
- is_accessed_from_inner_scope_(false),
+ force_context_allocation_(false),
is_used_(false) {
// names must be canonicalized for fast equality checks
ASSERT(name->IsSymbol());
Index: src/variables.h
diff --git a/src/variables.h b/src/variables.h
index
e23e00bd38081da8a1805955230859e52644615f..b09adb45101a9286e4adfd4a6f9c9cbaed152231
100644
--- a/src/variables.h
+++ b/src/variables.h
@@ -92,12 +92,12 @@ class Variable: public ZoneObject {
Handle<String> name() const { return name_; }
VariableMode mode() const { return mode_; }
- bool is_accessed_from_inner_scope() const {
- return is_accessed_from_inner_scope_;
+ bool has_forced_context_allocation() const {
+ return force_context_allocation_;
}
- void MarkAsAccessedFromInnerScope() {
+ void ForceContextAllocation() {
ASSERT(mode_ != TEMPORARY);
- is_accessed_from_inner_scope_ = true;
+ force_context_allocation_ = true;
}
bool is_used() { return is_used_; }
void set_is_used(bool flag) { is_used_ = flag; }
@@ -172,7 +172,7 @@ class Variable: public ZoneObject {
bool is_valid_LHS_;
// Usage info.
- bool is_accessed_from_inner_scope_; // set by variable resolver
+ bool force_context_allocation_; // set by variable resolver
bool is_used_;
};
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