PreParsing inner funcs: make scope analysis more complete.

This adds tracking the following:
- Declarations created by catch (potentially destructuring)
- Declarations created by for-each (potentially destructuring)
- Class declarations

BUG=v8:5501, v8:5516

Review-Url: https://codereview.chromium.org/2617923003
Cr-Commit-Position: refs/heads/master@{#42129}

src/ast/scopes.cc

@@ -1032,11 +1032,14 @@ void Scope::DeclareVariableName(const AstRawString* name, VariableMode mode) {
   if (mode == VAR && !is_declaration_scope()) {
     return GetDeclarationScope()->DeclareVariableName(name, mode);
   }
-  DCHECK(!is_catch_scope());
   DCHECK(!is_with_scope());
   DCHECK(!is_eval_scope());
-  DCHECK(is_declaration_scope() ||
-         (IsLexicalVariableMode(mode) && is_block_scope()));
+  // Unlike DeclareVariable, DeclareVariableName allows declaring variables in
+  // catch scopes: Parser::RewriteCatchPattern bypasses DeclareVariable by
+  // calling DeclareLocal directly, and it doesn't make sense to add a similar
+  // bypass mechanism for PreParser.
+  DCHECK(is_declaration_scope() || (IsLexicalVariableMode(mode) &&
+                                    (is_block_scope() || is_catch_scope())));
   DCHECK(scope_info_.is_null());
 
   // Declare the variable in the declaration scope.

src/parsing/parser.cc

@@ -1892,6 +1892,7 @@ void Parser::DesugarBindingInForEachStatement(ForInfo* for_info,
                                               Block** body_block,
                                               Expression** each_variable,
                                               bool* ok) {
+  DCHECK(for_info->parsing_result.declarations.length() == 1);
   DeclarationParsingResult::Declaration& decl =
       for_info->parsing_result.declarations[0];
   Variable* temp = NewTemporary(ast_value_factory()->dot_for_string());

src/parsing/preparser.h

@@ -1049,7 +1049,22 @@ class PreParser : public ParserBase<PreParser> {
       PreParserStatementList cases, Scope* scope) {
     return PreParserStatement::Default();
   }
-  V8_INLINE void RewriteCatchPattern(CatchInfo* catch_info, bool* ok) {}
+
+  V8_INLINE void RewriteCatchPattern(CatchInfo* catch_info, bool* ok) {
+    if (track_unresolved_variables_) {
+      if (catch_info->name.string_ != nullptr) {
+        // Unlike in the parser, we need to declare the catch variable as LET
+        // variable, so that it won't get hoisted out of the scope.
+        catch_info->scope->DeclareVariableName(catch_info->name.string_, LET);
+      }
+      if (catch_info->pattern.variables_ != nullptr) {
+        for (auto variable : *catch_info->pattern.variables_) {
+          scope()->DeclareVariableName(variable->raw_name(), LET);
+        }
+      }
+    }
+  }
+
   V8_INLINE void ValidateCatchBlock(const CatchInfo& catch_info, bool* ok) {}
   V8_INLINE PreParserStatement RewriteTryStatement(
       PreParserStatement try_block, PreParserStatement catch_block,
@@ -1084,6 +1099,12 @@ class PreParser : public ParserBase<PreParser> {
   DeclareClass(PreParserIdentifier variable_name, PreParserExpression value,
                ZoneList<const AstRawString*>* names, int class_token_pos,
                int end_pos, bool* ok) {
+    // Preparser shouldn't be used in contexts where we need to track the names.
+    DCHECK_NULL(names);
+    if (variable_name.string_ != nullptr) {
+      DCHECK(track_unresolved_variables_);
+      scope()->DeclareVariableName(variable_name.string_, LET);
+    }
     return PreParserStatement::Default();
   }
   V8_INLINE void DeclareClassVariable(PreParserIdentifier name,
@@ -1264,9 +1285,18 @@ class PreParser : public ParserBase<PreParser> {
   V8_INLINE PreParserStatement RewriteForVarInLegacy(const ForInfo& for_info) {
     return PreParserStatement::Null();
   }
+
   V8_INLINE void DesugarBindingInForEachStatement(
       ForInfo* for_info, PreParserStatement* body_block,
-      PreParserExpression* each_variable, bool* ok) {}
+      PreParserExpression* each_variable, bool* ok) {
+    if (track_unresolved_variables_) {
+      DCHECK(for_info->parsing_result.declarations.length() == 1);
+      DeclareAndInitializeVariables(
+          PreParserStatement::Default(), &for_info->parsing_result.descriptor,
+          &for_info->parsing_result.declarations[0], nullptr, ok);
+    }
+  }
+
   V8_INLINE PreParserStatement CreateForEachStatementTDZ(
       PreParserStatement init_block, const ForInfo& for_info, bool* ok) {
     return init_block;

test/cctest/test-parsing.cc

@@ -8805,62 +8805,76 @@ TEST(NoPessimisticContextAllocation) {
       {"function inner() { ({y, x: my_var}) => { }}", false},
       {"function inner() { ({y, x: my_var} = {y: 0, x: 0}) => my_var;}", false},
       {"function inner() { ({y, x: my_var} = {y: 0, x: 0}) => { }}", false},
+      {"function inner() { try { } catch (my_var) { my_var; } }", false},
+      {"function inner() { try { } catch ([a, my_var, b]) { my_var; } }",
+       false},
+      {"function inner() { try { } catch ({x: my_var}) { my_var; } }", false},
+      {"function inner() { try { } catch ({y, x: my_var}) { my_var; } }",
+       false},
+      {"function inner() { try { } catch ({my_var}) { my_var; } }", false},
+      {"function inner() { for (let my_var in {}) { my_var; } }", false},
+      {"function inner() { for (let my_var in {}) { } }", false},
+      {"function inner() { for (let my_var of []) { my_var; } }", false},
+      {"function inner() { for (let my_var of []) { } }", false},
+      {"function inner() { for (let [a, my_var, b] in {}) { my_var; } }",
+       false},
+      {"function inner() { for (let [a, my_var, b] of []) { my_var; } }",
+       false},
+      {"function inner() { for (let {x: my_var} in {}) { my_var; } }", false},
+      {"function inner() { for (let {x: my_var} of []) { my_var; } }", false},
+      {"function inner() { for (let {my_var} in {}) { my_var; } }", false},
+      {"function inner() { for (let {my_var} of []) { my_var; } }", false},
+      {"function inner() { for (let {y, x: my_var} in {}) { my_var; } }",
+       false},
+      {"function inner() { for (let {y, x: my_var} of []) { my_var; } }",
+       false},
+      {"function inner() { for (let {a, my_var} in {}) { my_var; } }", false},
+      {"function inner() { for (let {a, my_var} of []) { my_var; } }", false},
+      {"function inner() { for (var my_var in {}) { my_var; } }", false},
+      {"function inner() { for (var my_var in {}) { } }", false},
+      {"function inner() { for (var my_var of []) { my_var; } }", false},
+      {"function inner() { for (var my_var of []) { } }", false},
+      {"function inner() { for (var [a, my_var, b] in {}) { my_var; } }",
+       false},
+      {"function inner() { for (var [a, my_var, b] of []) { my_var; } }",
+       false},
+      {"function inner() { for (var {x: my_var} in {}) { my_var; } }", false},
+      {"function inner() { for (var {x: my_var} of []) { my_var; } }", false},
+      {"function inner() { for (var {my_var} in {}) { my_var; } }", false},
+      {"function inner() { for (var {my_var} of []) { my_var; } }", false},
+      {"function inner() { for (var {y, x: my_var} in {}) { my_var; } }",
+       false},
+      {"function inner() { for (var {y, x: my_var} of []) { my_var; } }",
+       false},
+      {"function inner() { for (var {a, my_var} in {}) { my_var; } }", false},
+      {"function inner() { for (var {a, my_var} of []) { my_var; } }", false},
+      {"function inner() { for (var my_var in {}) { } my_var; }", false},
+      {"function inner() { for (var my_var of []) { } my_var; }", false},
+      {"function inner() { for (var [a, my_var, b] in {}) { } my_var; }",
+       false},
+      {"function inner() { for (var [a, my_var, b] of []) { } my_var; }",
+       false},
+      {"function inner() { for (var {x: my_var} in {}) { } my_var; }", false},
+      {"function inner() { for (var {x: my_var} of []) { } my_var; }", false},
+      {"function inner() { for (var {my_var} in {}) { } my_var; }", false},
+      {"function inner() { for (var {my_var} of []) { } my_var; }", false},
+      {"function inner() { for (var {y, x: my_var} in {}) { } my_var; }",
+       false},
+      {"function inner() { for (var {y, x: my_var} of []) { } my_var; }",
+       false},
+      {"function inner() { for (var {a, my_var} in {}) { } my_var; }", false},
+      {"function inner() { for (var {a, my_var} of []) { } my_var; }", false},
+      {"function inner() { class my_var {}; my_var }", false},
       // In the following cases we still context allocate pessimistically:
       {"function inner() { function my_var() {} my_var; }", true},
       {"function inner() { if (true) { function my_var() {} }  my_var; }",
        true},
-      {"function inner() { try { } catch (my_var) { my_var; } }", true},
-      {"function inner() { try { } catch ([a, my_var, b]) { my_var; } }", true},
-      {"function inner() { try { } catch ({x: my_var}) { my_var; } }", true},
-      {"function inner() { try { } catch ({y, x: my_var}) { my_var; } }", true},
-      {"function inner() { try { } catch ({my_var}) { my_var; } }", true},
       {"function inner() { for (let my_var = 0; my_var < 1; ++my_var) { my_var "
        "} }",
        true},
       {"function inner() { for (let a = 0, my_var = 0; my_var < 1; ++my_var) { "
        "my_var } }",
        true},
-      {"function inner() { for (let my_var in {}) { my_var; } }", true},
-      {"function inner() { for (let my_var in {}) { } }", true},
-      {"function inner() { for (let my_var of []) { my_var; } }", true},
-      {"function inner() { for (let my_var of []) { } }", true},
-      {"function inner() { for (let [a, my_var, b] in {}) { my_var; } }", true},
-      {"function inner() { for (let [a, my_var, b] of []) { my_var; } }", true},
-      {"function inner() { for (let {x: my_var} in {}) { my_var; } }", true},
-      {"function inner() { for (let {x: my_var} of []) { my_var; } }", true},
-      {"function inner() { for (let {my_var} in {}) { my_var; } }", true},
-      {"function inner() { for (let {my_var} of []) { my_var; } }", true},
-      {"function inner() { for (let {y, x: my_var} in {}) { my_var; } }", true},
-      {"function inner() { for (let {y, x: my_var} of []) { my_var; } }", true},
-      {"function inner() { for (let {a, my_var} in {}) { my_var; } }", true},
-      {"function inner() { for (let {a, my_var} of []) { my_var; } }", true},
-      {"function inner() { for (var my_var in {}) { my_var; } }", true},
-      {"function inner() { for (var my_var in {}) { } }", true},
-      {"function inner() { for (var my_var of []) { my_var; } }", true},
-      {"function inner() { for (var my_var of []) { } }", true},
-      {"function inner() { for (var [a, my_var, b] in {}) { my_var; } }", true},
-      {"function inner() { for (var [a, my_var, b] of []) { my_var; } }", true},
-      {"function inner() { for (var {x: my_var} in {}) { my_var; } }", true},
-      {"function inner() { for (var {x: my_var} of []) { my_var; } }", true},
-      {"function inner() { for (var {my_var} in {}) { my_var; } }", true},
-      {"function inner() { for (var {my_var} of []) { my_var; } }", true},
-      {"function inner() { for (var {y, x: my_var} in {}) { my_var; } }", true},
-      {"function inner() { for (var {y, x: my_var} of []) { my_var; } }", true},
-      {"function inner() { for (var {a, my_var} in {}) { my_var; } }", true},
-      {"function inner() { for (var {a, my_var} of []) { my_var; } }", true},
-      {"function inner() { for (var my_var in {}) { } my_var; }", true},
-      {"function inner() { for (var my_var of []) { } my_var; }", true},
-      {"function inner() { for (var [a, my_var, b] in {}) { } my_var; }", true},
-      {"function inner() { for (var [a, my_var, b] of []) { } my_var; }", true},
-      {"function inner() { for (var {x: my_var} in {}) { } my_var; }", true},
-      {"function inner() { for (var {x: my_var} of []) { } my_var; }", true},
-      {"function inner() { for (var {my_var} in {}) { } my_var; }", true},
-      {"function inner() { for (var {my_var} of []) { } my_var; }", true},
-      {"function inner() { for (var {y, x: my_var} in {}) { } my_var; }", true},
-      {"function inner() { for (var {y, x: my_var} of []) { } my_var; }", true},
-      {"function inner() { for (var {a, my_var} in {}) { } my_var; }", true},
-      {"function inner() { for (var {a, my_var} of []) { } my_var; }", true},
-      {"function inner() { class my_var {}; my_var }", true},
   };
 
   for (unsigned i = 0; i < arraysize(inners); ++i) {