Changeset 38047 in webkit for trunk/JavaScriptCore/VM/CodeGenerator.cpp

Timestamp:

Oct 31, 2008, 12:59:08 PM (17 years ago)

Author:

[email protected]

Message:

2008-10-30 Geoffrey Garen <​[email protected]>

Reviewed by Oliver Hunt.

Fixed a small bit of ​https://bugs.webkit.org/show_bug.cgi?id=21962
AST uses way too much memory

Removed a word from StatementNode by nixing LabelStack and turning it
into a compile-time data structure managed by CodeGenerator.

v8 tests and SunSpider, run by Gavin, report no change.

• GNUmakefile.am:
• JavaScriptCore.order:
• JavaScriptCore.pri:
• JavaScriptCore.vcproj/JavaScriptCore/JavaScriptCore.vcproj:
• JavaScriptCore.xcodeproj/project.pbxproj:
• kjs/AllInOneFile.cpp:
• JavaScriptCoreSources.bkl: I sure hope this builds!

• VM/CodeGenerator.cpp: (JSC::CodeGenerator::CodeGenerator): (JSC::CodeGenerator::newLabelScope): (JSC::CodeGenerator::breakTarget): (JSC::CodeGenerator::continueTarget):
• VM/CodeGenerator.h: Nixed the JumpContext system because it depended on a LabelStack in the AST, and it was a little cumbersome on the client side. Replaced with LabelScope, which tracks all break / continue information in the CodeGenerator, just like we track LabelIDs and other stacks of compile-time data.

• kjs/LabelScope.h: Added. (JSC::LabelScope::): (JSC::LabelScope::LabelScope): (JSC::LabelScope::ref): (JSC::LabelScope::deref): (JSC::LabelScope::refCount): (JSC::LabelScope::breakTarget): (JSC::LabelScope::continueTarget): (JSC::LabelScope::type): (JSC::LabelScope::name): (JSC::LabelScope::scopeDepth): Simple abstraction for holding everything you might want to know about a break-able / continue-able scope.

• kjs/LabelStack.cpp: Removed.
• kjs/LabelStack.h: Removed.

• kjs/grammar.y: No need to push labels at parse time -- we don't store LabelStacks in the AST anymore.

• kjs/nodes.cpp: (JSC::DoWhileNode::emitCode): (JSC::WhileNode::emitCode): (JSC::ForNode::emitCode): (JSC::ForInNode::emitCode): (JSC::ContinueNode::emitCode): (JSC::BreakNode::emitCode): (JSC::SwitchNode::emitCode): (JSC::LabelNode::emitCode):
• kjs/nodes.h: (JSC::StatementNode::): (JSC::LabelNode::): Use LabelScope where we used to use JumpContext. Simplified a bunch of code. Touched up label-related error messages a bit.

• kjs/nodes2string.cpp: (JSC::LabelNode::streamTo): Updated for rename.

File:

• trunk/JavaScriptCore/VM/CodeGenerator.cpp (modified) (5 diffs)

trunk/JavaScriptCore/VM/CodeGenerator.cpp

@@ -205 +205 @@
     , m_dynamicScopeDepth(0)
     , m_codeType(GlobalCode)
-    , m_continueDepth(0)
     , m_nextGlobal(-1)
     , m_globalData(&scopeChain.globalObject()->globalExec()->globalData())
@@ -283 +282 @@
     , m_dynamicScopeDepth(0)
     , m_codeType(FunctionCode)
-    , m_continueDepth(0)
     , m_globalData(&scopeChain.globalObject()->globalExec()->globalData())
     , m_lastOpcodeID(op_end)
@@ -354 +352 @@
     , m_dynamicScopeDepth(0)
     , m_codeType(EvalCode)
-    , m_continueDepth(0)
     , m_globalData(&scopeChain.globalObject()->globalExec()->globalData())
     , m_lastOpcodeID(op_end)
@@ -450 +447 @@
         newRegister();
     return &m_calleeRegisters.last();
+}
+
+PassRefPtr<LabelScope> CodeGenerator::newLabelScope(LabelScope::Type type, const Identifier* name)
+{
+    // Reclaim free label scopes.
+    while (m_labelScopes.size() && !m_labelScopes.last().refCount())
+        m_labelScopes.removeLast();
+
+    // Allocate new label scope.
+    LabelScope scope(type, name, scopeDepth(), newLabel(), type == LabelScope::Loop ? newLabel() : 0); // Only loops have continue targets.
+    m_labelScopes.append(scope);
+    return &m_labelScopes.last();
 }
 
@@ -1357 +1366 @@
 }
 
-void CodeGenerator::pushJumpContext(LabelStack* labels, LabelID* continueTarget, LabelID* breakTarget, bool isValidUnlabeledBreakTarget)
-{
-    JumpContext context = { labels, continueTarget, breakTarget, scopeDepth(), isValidUnlabeledBreakTarget };
-    m_jumpContextStack.append(context);
-    if (continueTarget)
-        m_continueDepth++;
-}
-
-void CodeGenerator::popJumpContext()
-{
-    ASSERT(m_jumpContextStack.size());
-    if (m_jumpContextStack.last().continueTarget)
-        m_continueDepth--;
-    m_jumpContextStack.removeLast();
-}
-
-JumpContext* CodeGenerator::jumpContextForContinue(const Identifier& label)
-{
-    if(!m_jumpContextStack.size())
+LabelScope* CodeGenerator::breakTarget(const Identifier& name)
+{
+    // Reclaim free label scopes.
+    while (m_labelScopes.size() && !m_labelScopes.last().refCount())
+        m_labelScopes.removeLast();
+
+    if (!m_labelScopes.size())
         return 0;
 
-    if (label.isEmpty()) {
-        for (int i = m_jumpContextStack.size() - 1; i >= 0; i--) {
-            JumpContext* scope = &m_jumpContextStack[i];
-            if (scope->continueTarget)
+    // We special-case the following, which is a syntax error in Firefox:
+    // label:
+    //     break;
+    if (name.isEmpty()) {
+        for (int i = m_labelScopes.size() - 1; i >= 0; --i) {
+            LabelScope* scope = &m_labelScopes[i];
+            if (scope->type() != LabelScope::NamedLabel) {
+                ASSERT(scope->breakTarget());
                 return scope;
+            }
         }
         return 0;
     }
 
-    for (int i = m_jumpContextStack.size() - 1; i >= 0; i--) {
-        JumpContext* scope = &m_jumpContextStack[i];
-        if (scope->labels->contains(label))
+    for (int i = m_labelScopes.size() - 1; i >= 0; --i) {
+        LabelScope* scope = &m_labelScopes[i];
+        if (scope->name() && *scope->name() == name) {
+            ASSERT(scope->breakTarget());
             return scope;
+        }
     }
     return 0;
 }
 
-JumpContext* CodeGenerator::jumpContextForBreak(const Identifier& label)
-{
-    if(!m_jumpContextStack.size())
+LabelScope* CodeGenerator::continueTarget(const Identifier& name)
+{
+    // Reclaim free label scopes.
+    while (m_labelScopes.size() && !m_labelScopes.last().refCount())
+        m_labelScopes.removeLast();
+
+    if (!m_labelScopes.size())
         return 0;
 
-    if (label.isEmpty()) {
-        for (int i = m_jumpContextStack.size() - 1; i >= 0; i--) {
-            JumpContext* scope = &m_jumpContextStack[i];
-            if (scope->isValidUnlabeledBreakTarget)
+    if (name.isEmpty()) {
+        for (int i = m_labelScopes.size() - 1; i >= 0; --i) {
+            LabelScope* scope = &m_labelScopes[i];
+            if (scope->type() == LabelScope::Loop) {
+                ASSERT(scope->continueTarget());
                 return scope;
+            }
         }
         return 0;
     }
 
-    for (int i = m_jumpContextStack.size() - 1; i >= 0; i--) {
-        JumpContext* scope = &m_jumpContextStack[i];
-        if (scope->labels->contains(label))
-            return scope;
+    // Continue to the loop nested nearest to the label scope that matches
+    // 'name'.
+    LabelScope* result = 0;
+    for (int i = m_labelScopes.size() - 1; i >= 0; --i) {
+        LabelScope* scope = &m_labelScopes[i];
+        if (scope->type() == LabelScope::Loop) {
+            ASSERT(scope->continueTarget());
+            result = scope;
+        }
+        if (scope->name() && *scope->name() == name)
+            return result; // may be 0
     }
     return 0;