allow static keyword before closure

PHP added this in 5.4 so that you can say your closure shouldn't capture ##$this##. https://wiki.php.net/rfc/closures

Should we add it? Many of their unit tests use it.

Instead of putting a boolean somewhere I used the same attr framework and set the static bit there. Thoughts? It only needs one change in the ##FPushFunc##.

hphp/compiler/analysis/block_scope.h

@@ -178,6 +178,7 @@ public:
   VariableTablePtr getVariables() { return m_variables;}
   ConstantTablePtr getConstants() { return m_constants;}
   ClassScopeRawPtr getContainingClass();
+  FunctionScopeRawPtr getContainingNonClosureFunction();
   FunctionScopeRawPtr getContainingFunction() const {
     return FunctionScopeRawPtr(is(FunctionScope) ?
                                (HPHP::FunctionScope*)this : 0);
@@ -341,8 +342,6 @@ protected:
   int m_updated;
   int m_runId;
 private:
-  FunctionScopeRawPtr getContainingNonClosureFunction();
-
   Marks m_mark;
   BlockScopeRawPtrFlagsPtrVec  m_orderedDeps;
   BlockScopeRawPtrFlagsVec     m_orderedUsers;

hphp/compiler/analysis/file_scope.cpp

@@ -396,6 +396,7 @@ FunctionScopePtr FileScope::createPseudoMain(AnalysisResultConstPtr ar) {
   StatementListPtr st = m_tree;
   FunctionStatementPtr f
     (new FunctionStatement(BlockScopePtr(), LocationPtr(),
+                           ModifierExpressionPtr(),
                            false, pseudoMainName(),
                            ExpressionListPtr(), st, 0, "",
                            ExpressionListPtr()));

hphp/compiler/analysis/function_scope.cpp

@@ -331,6 +331,11 @@ bool FunctionScope::needsActRec() const {
   return res;
 }
 
+bool FunctionScope::mayContainThis() {
+  return inPseudoMain() || getContainingClass() ||
+    (isClosure() && !m_modifiers->isStatic());
+}
+
 bool FunctionScope::isClosure() const {
   return ParserBase::IsClosureName(name());
 }

hphp/compiler/analysis/function_scope.h

@@ -109,6 +109,7 @@ public:
   bool hasImpl() const;
   void setDirectInvoke() { m_directInvoke = true; }
   bool hasDirectInvoke() const { return m_directInvoke; }
+  bool mayContainThis();
   bool isClosure() const;
   bool isGenerator() const;
   bool isGeneratorFromClosure() const;

hphp/compiler/expression/closure_expression.cpp

@@ -172,6 +172,13 @@ void ClosureExpression::analyzeProgram(AnalysisResultPtr ar) {
       }
     }
   }
+
+  FunctionScopeRawPtr container = 
+    getFunctionScope()->getContainingNonClosureFunction();
+  if (container && container->isStatic()) {
+    m_func->getModifiers()->add(T_STATIC);
+  }
+
 }
 
 TypePtr ClosureExpression::inferTypes(AnalysisResultPtr ar, TypePtr type,

hphp/compiler/expression/simple_variable.cpp

@@ -146,7 +146,7 @@ void SimpleVariable::analyzeProgram(AnalysisResultPtr ar) {
 
   if (ar->getPhase() == AnalysisResult::AnalyzeAll) {
     if (FunctionScopePtr func = getFunctionScope()) {
-      if (m_name == "this" && (func->inPseudoMain() || getClassScope())) {
+      if (m_name == "this" && func->mayContainThis()) {
         func->setContainsThis();
         m_this = true;
         if (!hasContext(ObjectContext)) {

hphp/compiler/parser/parser.cpp

@@ -789,8 +789,13 @@ void Parser::fixStaticVars() {
   m_staticVars.pop_back();
 }
 
-void Parser::onFunction(Token &out, Token &ret, Token &ref, Token &name,
-                        Token &params, Token &stmt, Token *attr) {
+void Parser::onFunction(Token &out, Token *modifiers, Token &ret, Token &ref, 
+                        Token &name, Token &params, Token &stmt, Token *attr) {
+  
+  ModifierExpressionPtr exp = modifiers?
+    dynamic_pointer_cast<ModifierExpression>(modifiers->exp)
+    : NEW_EXP0(ModifierExpression);
+
   const string &retType = ret.text();
   if (!retType.empty() && !ret.check()) {
     PARSE_ERROR("Return type hint is not supported yet");
@@ -825,7 +830,7 @@ void Parser::onFunction(Token &out, Token &ret, Token &ref, Token &name,
     Token new_params;
     prepare_generator(this, stmt, new_params, funcContext.numYields);
 
-    func = NEW_STMT(FunctionStatement, ref->num(), closureName,
+    func = NEW_STMT(FunctionStatement, exp, ref->num(), closureName,
                     dynamic_pointer_cast<ExpressionList>(new_params->exp),
                     dynamic_pointer_cast<StatementList>(stmt->stmt),
                     attribute, comment, ExpressionListPtr());
@@ -876,7 +881,7 @@ void Parser::onFunction(Token &out, Token &ret, Token &ref, Token &name,
       attrList = dynamic_pointer_cast<ExpressionList>(attr->exp);
     }
 
-    func = NEW_STMT(FunctionStatement, ref->num(), funcName,
+    func = NEW_STMT(FunctionStatement, exp, ref->num(), funcName,
                     old_params, dynamic_pointer_cast<StatementList>(stmt->stmt),
                     attribute, comment, attrList);
     out->stmt = func;
@@ -1540,10 +1545,16 @@ void Parser::onClosureStart(Token &name) {
   onFunctionStart(name, true);
 }
 
-void Parser::onClosure(Token &out, Token &ret, Token &ref, Token &params,
-                       Token &cparams, Token &stmts) {
-  Token func, name;
-  onFunction(func, ret, ref, name, params, stmts, 0);
+void Parser::onClosure(Token &out, Token &ret, Token &ref, Token &params, 
+                       Token &cparams, Token &stmts, bool is_static) {
+  Token func, name, modifiers;
+  
+  ModifierExpressionPtr modifier_exp = NEW_EXP0(ModifierExpression);
+  modifiers->exp = modifier_exp;
+  if (is_static) {
+    modifier_exp->add(T_STATIC);
+  }
+  onFunction(func, &modifiers, ret, ref, name, params, stmts, 0);
 
   out.reset();
   out->exp = NEW_EXP(ClosureExpression,

hphp/compiler/parser/parser.h

@@ -167,8 +167,8 @@ public:
   void onClassConst(Token &out, Token &cls, Token &name, bool text);
   void fixStaticVars();
   void onFunctionStart(Token &name, bool doPushComment = true);
-  void onFunction(Token &out, Token &ret, Token &ref, Token &name,
-                  Token &params, Token &stmt, Token *attr);
+  void onFunction(Token &out, Token *modifier, Token &ret, Token &ref, 
+                  Token &name, Token &params, Token &stmt, Token *attr);
   void onParam(Token &out, Token *params, Token &type, Token &var,
                bool ref, Token *defValue, Token *attr);
   void onClassStart(int type, Token &name);
@@ -230,7 +230,7 @@ public:
 
   void onClosureStart(Token &name);
   void onClosure(Token &out, Token &ret, Token &ref, Token &params,
-                 Token &cparams, Token &stmts);
+                 Token &cparams, Token &stmts, bool is_static);
   void onClosureParam(Token &out, Token *params, Token &param, bool ref);
   void onLabel(Token &out, Token &label);
   void onGoto(Token &out, Token &label, bool limited);

hphp/compiler/statement/function_statement.cpp

@@ -35,11 +35,11 @@ using namespace HPHP;
 
 FunctionStatement::FunctionStatement
 (STATEMENT_CONSTRUCTOR_PARAMETERS,
- bool ref, const std::string &name, ExpressionListPtr params,
- StatementListPtr stmt, int attr, const std::string &docComment,
- ExpressionListPtr attrList)
+ ModifierExpressionPtr modifiers, bool ref, const std::string &name, 
+ ExpressionListPtr params, StatementListPtr stmt, int attr, const 
+ std::string &docComment, ExpressionListPtr attrList)
   : MethodStatement(STATEMENT_CONSTRUCTOR_PARAMETER_VALUES(FunctionStatement),
-                    ModifierExpressionPtr(), ref, name, params, stmt, attr,
+                    modifiers, ref, name, params, stmt, attr,
                     docComment, attrList, false), m_ignored(false) {
 }
 

hphp/compiler/statement/function_statement.h

@@ -31,9 +31,9 @@ DECLARE_BOOST_TYPES(FunctionStatement);
 class FunctionStatement : public MethodStatement {
 public:
   FunctionStatement(STATEMENT_CONSTRUCTOR_PARAMETERS,
-                    bool ref, const std::string &name,
-                    ExpressionListPtr params, StatementListPtr stmt,
-                    int attr,
+                    ModifierExpressionPtr modifiers, bool ref, 
+                    const std::string &name, ExpressionListPtr params, 
+                    StatementListPtr stmt, int attr,
                     const std::string &docComment,
                     ExpressionListPtr attrList);
 

hphp/runtime/ext/ext_closure.cpp

@@ -41,18 +41,25 @@ void c_Closure::t___construct() {
     VM::ActRec* childClosure = context->getPrevVMState(me);
     ar = context->getPrevVMState(childClosure);
   }
+  
+  static StringData* invokeName = StringData::GetStaticString("__invoke");
+  VM::Func* invokeFunc = getVMClass()->lookupMethod(invokeName);
 
-  // I don't care if it is a $this or a late bound class because we will just
-  // put it back in the same place on an ActRec.
-  m_thisOrClass = ar->m_this;
-  if (ar->hasThis()) {
-    ar->getThis()->incRefCount();
+  if (invokeFunc->attrs() & VM::AttrStatic) {
+    // Only set the class for static closures
+    m_thisOrClass = (ObjectData*)(intptr_t(ar->m_func->cls()) | 1LL);
+  } else {
+    // I don't care if it is a $this or a late bound class because we will just
+    // put it back in the same place on an ActRec.
+    m_thisOrClass = ar->m_this;
+    if (ar->hasThis()) {
+      ar->getThis()->incRefCount();
+    }
   }
 
   // Change my __invoke's m_cls to be the same as my creator's
-  static StringData* invokeName = StringData::GetStaticString("__invoke");
   VM::Class* scope = ar->m_func->cls();
-  m_func = getVMClass()->lookupMethod(invokeName)->cloneAndSetClass(scope);
+  m_func = invokeFunc->cloneAndSetClass(scope);
 }
 
 ObjectData* c_Closure::clone() {

hphp/runtime/vm/bytecode.cpp

@@ -5582,7 +5582,7 @@ inline void OPTBLD_INLINE VMExecutionContext::iopFPushFunc(PC& pc) {
   ar->m_func = func;
   arSetSfp(ar, m_fp);
   if (origObj) {
-    if (func->attrs() & AttrStatic) {
+    if (func->attrs() & AttrStatic && !func->isClosureBody()) {
       ar->setClass(origObj->getVMClass());
       decRefObj(origObj);
     } else {

hphp/runtime/vm/translator/hopt/irtranslator.cpp

@@ -1160,7 +1160,8 @@ void
 TranslatorX64::irTranslateThis(const Tracelet &t,
                              const NormalizedInstruction &i) {
   assert(i.outStack && !i.outLocal);
-  assert(curFunc()->isPseudoMain() || curFunc()->cls());
+  assert(curFunc()->isPseudoMain() || curFunc()->cls() ||
+         curFunc()->isClosureBody());
 
   HHIR_EMIT(This);
 }
@@ -1169,7 +1170,8 @@ void
 TranslatorX64::irTranslateBareThis(const Tracelet &t,
                                   const NormalizedInstruction &i) {
   assert(i.outStack && !i.outLocal);
-  assert(curFunc()->isPseudoMain() || curFunc()->cls());
+  assert(curFunc()->isPseudoMain() || curFunc()->cls() ||
+         curFunc()->isClosureBody());
 
   HHIR_EMIT(BareThis, (i.imm[0].u_OA));
 }

hphp/runtime/vm/translator/translator-x64.cpp

@@ -9377,7 +9377,8 @@ TranslatorX64::translateThis(const Tracelet &t,
   }
 
   assert(!i.outLocal);
-  assert(curFunc()->isPseudoMain() || curFunc()->cls());
+  assert(curFunc()->isPseudoMain() || curFunc()->cls() || 
+         curFunc()->isClosureBody());
   m_regMap.allocOutputRegs(i);
   PhysReg out = getReg(i.outStack->location);
   a.   load_reg64_disp_reg64(rVmFp, AROFF(m_this), out);
@@ -9396,7 +9397,7 @@ TranslatorX64::translateBareThis(const Tracelet &t,
     return;
   }
   assert(!i.outLocal);
-  assert(curFunc()->cls());
+  assert(curFunc()->cls() || curFunc()->isClosureBody());
   ScratchReg outScratch(m_regMap);
   PhysReg out = r(outScratch);
   PhysReg base;

hphp/test/vm/closure_recursive_bad.php.exp

@@ -1,2 +1 @@
-HipHop Notice:  Undefined variable: this in hphp/test/vm/closure_recursive_bad.php on line 6
-HipHop Fatal error: Uncaught exception 'BadMethodCallException' with message 'Call to a member function d() on a non-object' in hphp/test/vm/closure_recursive_bad.php:6\nStack trace:\n#0 hphp/test/vm/closure_recursive_bad.php(17): {closure}()\n#1 {main}
+HipHop Fatal error: $this is null in hphp/test/vm/closure_recursive_bad.php on line 6

hphp/test/vm/closure_static.php

@@ -0,0 +1,32 @@
+<?php
+
+class A {
+  private $c = 1;
+
+  function b() {
+    $a = function () {
+      var_dump($this);
+    };
+    $a();
+
+    $a = static function () {
+      var_dump($this);
+    };
+    $a();
+  }
+
+  static function c() {
+    $a = function () {
+      var_dump($this);
+    };
+    $a();
+
+    $a = static function () {
+      var_dump($this);
+    };
+    $a();
+  }
+}
+
+(new A)->b();
+(new A)->c();

hphp/test/vm/closure_static.php.exp

@@ -0,0 +1,10 @@
+object(A)#1 (1) {
+  ["c":"A":private]=>
+  int(1)
+}
+HipHop Notice:  Undefined variable: this in hphp/test/vm/closure_static.php on line 13
+NULL
+HipHop Notice:  Undefined variable: this in hphp/test/vm/closure_static.php on line 20
+NULL
+HipHop Notice:  Undefined variable: this in hphp/test/vm/closure_static.php on line 25
+NULL

hphp/test/vm/closure_static.php.filter

@@ -0,0 +1 @@
+filepath.filter

hphp/util/parser/hphp.y

@@ -310,7 +310,7 @@ void create_generator(Parser *_p, Token &out, Token &params,
     _p->finishStatement(out, stmts2); out = 1;
   } else {
     out.reset();
-    _p->onFunction(out, ret, ref, name, params, scont, attr);
+    _p->onFunction(out, modifiers, ret, ref, name, params, scont, attr);
     origGenFunc = out;
   }
 }
@@ -1139,7 +1139,7 @@ function_declaration_statement:
     '(' parameter_list ')'
     sm_opt_return_type
     '{' inner_statement_list '}'       { Token t; t.reset();
-                                         _p->onFunction($$,t,$2,$3,$6,$10,0);
+                                         _p->onFunction($$,0,t,$2,$3,$6,$10,0);
                                          _p->popLabelInfo();
                                          _p->popTypeScope();}
   | non_empty_user_attributes function_loc
@@ -1149,7 +1149,7 @@ function_declaration_statement:
     '(' parameter_list ')'
     sm_opt_return_type
     '{' inner_statement_list '}'       { Token t; t.reset();
-                                         _p->onFunction($$,t,$3,$4,$7,$11,&$1);
+                                         _p->onFunction($$,0,t,$3,$4,$7,$11,&$1);
                                          _p->popLabelInfo();
                                          _p->popTypeScope();}
 ;
@@ -1717,12 +1717,21 @@ expr_no_variable:
   | array_literal                      { $$ = $1;}
   | '`' backticks_expr '`'             { _p->onEncapsList($$,'`',$2);}
   | T_PRINT expr                       { UEXP($$,$2,T_PRINT,1);}
-  | function_loc is_reference '('      { Token t; _p->onClosureStart(t);
+  | function_loc 
+    is_reference '('                   { Token t; _p->onClosureStart(t);
                                          _p->pushLabelInfo();}
     parameter_list ')'
     sm_opt_return_type lexical_vars
     '{' inner_statement_list '}'       { Token u; u.reset();
-                                         _p->onClosure($$,u,$2,$5,$8,$10);
+                                         _p->onClosure($$,u,$2,$5,$8,$10,0);
+                                         _p->popLabelInfo();}
+  | T_STATIC function_loc 
+    is_reference '('                   { Token t; _p->onClosureStart(t);
+                                         _p->pushLabelInfo();}
+    parameter_list ')'
+    sm_opt_return_type lexical_vars
+    '{' inner_statement_list '}'       { Token u; u.reset();
+                                         _p->onClosure($$,u,$3,$6,$9,$11,1);
                                          _p->popLabelInfo();}
   | xhp_tag                            { $$ = $1;}
   | dim_expr                           { $$ = $1;}

hphp/util/parser/test/parser.h

@@ -316,9 +316,9 @@ struct Parser : ParserBase {
     X(name);
   }
 
-  void onFunction(Token& out, Token& ret, Token& ref, Token& name,
-                  Token& params, Token& stmt, Token* attr) {
-    X(ret, ref, name, params, stmt, attr);
+  void onFunction(Token& out, Token* modifiers, Token& ret, Token& ref, 
+                  Token& name, Token& params, Token& stmt, Token* attr) {
+    X(modifiers, ret, ref, name, params, stmt, attr);
   }
 
   void onParam(Token &out, Token *params, Token &type, Token &var,
@@ -482,9 +482,9 @@ struct Parser : ParserBase {
 
   void onThrow(Token &out, Token &expr) { X(expr); }
 
-  void onClosure(Token &out, Token &ret, Token &ref, Token &params,
-                 Token &cparams, Token &stmts) {
-    X(ret, ref, params, cparams, stmts);
+  void onClosure(Token &out, Token &ret, Token &ref, Token &params, 
+                 Token &cparams, Token &stmts, bool is_static) {
+    X(ret, ref, params, cparams, stmts, is_static);
   }
 
   void onClosureParam(Token &out, Token *params, Token &param, bool ref) {