Safe navigation operator

* compile.c (iseq_peephole_optimize): peephole optimization for
  branchnil jumps.
* compile.c (iseq_compile_each): generate save navigation operator
  code.
* insns.def (branchnil): new opcode to pop the tos and branch if
  it is nil.
* parse.y (NEW_QCALL, call_op, parser_yylex): parse token '.?'.
  [Feature #11537]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@52214 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 47 insertions, 34 deletions

diff --git a/parse.y b/parse.y
index 21d6131bcf..243ec51a48 100644
--- a/parse.y
+++ b/parse.y
@@ -371,6 +371,9 @@ static int parser_yyerror(struct parser_params*, const char*);
 #define ruby_coverage		(parser->coverage)
 #endif
 
+#define NODE_CALL_Q(q) (((q) == tDOTQ) ? NODE_QCALL : NODE_CALL)
+#define NEW_QCALL(q,r,m,a) NEW_NODE(NODE_CALL_Q(q),r,m,a)
+
 static int yylex(YYSTYPE*, struct parser_params*);
 
 #ifndef RIPPER
@@ -457,8 +460,8 @@ static NODE *node_assign_gen(struct parser_params*,NODE*,NODE*);
 #define node_assign(node1, node2) node_assign_gen(parser, (node1), (node2))
 
 static NODE *new_op_assign_gen(struct parser_params *parser, NODE *lhs, ID op, NODE *rhs);
-static NODE *new_attr_op_assign_gen(struct parser_params *parser, NODE *lhs, ID attr, ID op, NODE *rhs);
-#define new_attr_op_assign(lhs, type, attr, op, rhs) new_attr_op_assign_gen(parser, (lhs), (attr), (op), (rhs))
+static NODE *new_attr_op_assign_gen(struct parser_params *parser, NODE *lhs, ID atype, ID attr, ID op, NODE *rhs);
+#define new_attr_op_assign(lhs, type, attr, op, rhs) new_attr_op_assign_gen(parser, (lhs), (type), (attr), (op), (rhs))
 static NODE *new_const_op_assign_gen(struct parser_params *parser, NODE *lhs, ID op, NODE *rhs);
 #define new_const_op_assign(lhs, op, rhs) new_const_op_assign_gen(parser, (lhs), (op), (rhs))
 
@@ -844,7 +847,7 @@ static void token_info_pop(struct parser_params*, const char *token, size_t len)
 %type <node> mlhs mlhs_head mlhs_basic mlhs_item mlhs_node mlhs_post mlhs_inner
 %type <id>   fsym keyword_variable user_variable sym symbol operation operation2 operation3
 %type <id>   cname fname op f_rest_arg f_block_arg opt_f_block_arg f_norm_arg f_bad_arg
-%type <id>   f_kwrest f_label f_arg_asgn
+%type <id>   f_kwrest f_label f_arg_asgn call_op
 /*%%%*/
 /*%
 %type <val> program reswords then do dot_or_colon
@@ -869,6 +872,7 @@ static void token_info_pop(struct parser_params*, const char *token, size_t len)
 %token tASET		RUBY_TOKEN(ASET)   "[]="
 %token tLSHFT		RUBY_TOKEN(LSHFT)  "<<"
 %token tRSHFT		RUBY_TOKEN(RSHFT)  ">>"
+%token tDOTQ		RUBY_TOKEN(DOTQ)   ".?"
 %token tCOLON2		"::"
 %token tCOLON3		":: at EXPR_BEG"
 %token <id> tOP_ASGN	/* +=, -=  etc. */
@@ -1260,15 +1264,15 @@ stmt		: keyword_alias fitem {lex_state = EXPR_FNAME;} fitem
 			$$ = dispatch3(opassign, $$, $5, $6);
 		    %*/
 		    }
-		| primary_value '.' tIDENTIFIER tOP_ASGN command_call
+		| primary_value call_op tIDENTIFIER tOP_ASGN command_call
 		    {
 			value_expr($5);
-			$$ = new_attr_op_assign($1, '.', $3, $4, $5);
+			$$ = new_attr_op_assign($1, $2, $3, $4, $5);
 		    }
-		| primary_value '.' tCONSTANT tOP_ASGN command_call
+		| primary_value call_op tCONSTANT tOP_ASGN command_call
 		    {
 			value_expr($5);
-			$$ = new_attr_op_assign($1, '.', $3, $4, $5);
+			$$ = new_attr_op_assign($1, $2, $3, $4, $5);
 		    }
 		| primary_value tCOLON2 tCONSTANT tOP_ASGN command_call
 		    {
@@ -1456,24 +1460,24 @@ command		: fcall command_args       %prec tLOWEST
 			$$ = method_add_block($$, $3);
 		    %*/
 		    }
-		| primary_value '.' operation2 command_args	%prec tLOWEST
+		| primary_value call_op operation2 command_args	%prec tLOWEST
 		    {
 		    /*%%%*/
-			$$ = NEW_CALL($1, $3, $4);
+			$$ = NEW_QCALL($2, $1, $3, $4);
 			fixpos($$, $1);
 		    /*%
-			$$ = dispatch4(command_call, $1, ripper_id2sym('.'), $3, $4);
+			$$ = dispatch4(command_call, $1, ripper_id2sym($2), $3, $4);
 		    %*/
 		    }
-		| primary_value '.' operation2 command_args cmd_brace_block
+		| primary_value call_op operation2 command_args cmd_brace_block
 		    {
 		    /*%%%*/
 			block_dup_check($4,$5);
-		        $5->nd_iter = NEW_CALL($1, $3, $4);
+		        $5->nd_iter = NEW_QCALL($2, $1, $3, $4);
 			$$ = $5;
 			fixpos($$, $1);
 		    /*%
-			$$ = dispatch4(command_call, $1, ripper_id2sym('.'), $3, $4);
+			$$ = dispatch4(command_call, $1, ripper_id2sym($2), $3, $4);
 			$$ = method_add_block($$, $5);
 		    %*/
 		   }
@@ -1713,12 +1717,12 @@ mlhs_node	: user_variable
 			$$ = dispatch2(aref_field, $1, escape_Qundef($3));
 		    %*/
 		    }
-		| primary_value '.' tIDENTIFIER
+		| primary_value call_op tIDENTIFIER
 		    {
 		    /*%%%*/
 			$$ = attrset($1, $3);
 		    /*%
-			$$ = dispatch3(field, $1, ripper_id2sym('.'), $3);
+			$$ = dispatch3(field, $1, ripper_id2sym($2), $3);
 		    %*/
 		    }
 		| primary_value tCOLON2 tIDENTIFIER
@@ -1729,12 +1733,12 @@ mlhs_node	: user_variable
 			$$ = dispatch2(const_path_field, $1, $3);
 		    %*/
 		    }
-		| primary_value '.' tCONSTANT
+		| primary_value call_op tCONSTANT
 		    {
 		    /*%%%*/
 			$$ = attrset($1, $3);
 		    /*%
-			$$ = dispatch3(field, $1, ripper_id2sym('.'), $3);
+			$$ = dispatch3(field, $1, ripper_id2sym($2), $3);
 		    %*/
 		    }
 		| primary_value tCOLON2 tCONSTANT
@@ -1804,12 +1808,12 @@ lhs		: user_variable
 			$$ = dispatch2(aref_field, $1, escape_Qundef($3));
 		    %*/
 		    }
-		| primary_value '.' tIDENTIFIER
+		| primary_value call_op tIDENTIFIER
 		    {
 		    /*%%%*/
 			$$ = attrset($1, $3);
 		    /*%
-			$$ = dispatch3(field, $1, ripper_id2sym('.'), $3);
+			$$ = dispatch3(field, $1, ripper_id2sym($2), $3);
 		    %*/
 		    }
 		| primary_value tCOLON2 tIDENTIFIER
@@ -1820,12 +1824,12 @@ lhs		: user_variable
 			$$ = dispatch3(field, $1, ID2SYM(idCOLON2), $3);
 		    %*/
 		    }
-		| primary_value '.' tCONSTANT
+		| primary_value call_op tCONSTANT
 		    {
 		    /*%%%*/
 			$$ = attrset($1, $3);
 		    /*%
-			$$ = dispatch3(field, $1, ripper_id2sym('.'), $3);
+			$$ = dispatch3(field, $1, ripper_id2sym($2), $3);
 		    %*/
 		    }
 		| primary_value tCOLON2 tCONSTANT
@@ -2064,15 +2068,15 @@ arg		: lhs '=' arg
 			$$ = dispatch3(opassign, $1, $5, $6);
 		    %*/
 		    }
-		| primary_value '.' tIDENTIFIER tOP_ASGN arg
+		| primary_value call_op tIDENTIFIER tOP_ASGN arg
 		    {
 			value_expr($5);
-			$$ = new_attr_op_assign($1, '.', $3, $4, $5);
+			$$ = new_attr_op_assign($1, $2, $3, $4, $5);
 		    }
-		| primary_value '.' tCONSTANT tOP_ASGN arg
+		| primary_value call_op tCONSTANT tOP_ASGN arg
 		    {
 			value_expr($5);
-			$$ = new_attr_op_assign($1, '.', $3, $4, $5);
+			$$ = new_attr_op_assign($1, $2, $3, $4, $5);
 		    }
 		| primary_value tCOLON2 tIDENTIFIER tOP_ASGN arg
 		    {
@@ -3648,7 +3652,7 @@ method_call	: fcall paren_args
 			$$ = method_arg(dispatch1(fcall, $1), $2);
 		    %*/
 		    }
-		| primary_value '.' operation2
+		| primary_value call_op operation2
 		    {
 		    /*%%%*/
 			$<num>$ = ruby_sourceline;
@@ -3657,10 +3661,10 @@ method_call	: fcall paren_args
 		  opt_paren_args
 		    {
 		    /*%%%*/
-			$$ = NEW_CALL($1, $3, $5);
+			$$ = NEW_QCALL($2, $1, $3, $5);
 			nd_set_line($$, $<num>4);
 		    /*%
-			$$ = dispatch3(call, $1, ripper_id2sym('.'), $3);
+			$$ = dispatch3(call, $1, ripper_id2sym($2), $3);
 			$$ = method_optarg($$, $5);
 		    %*/
 		    }
@@ -3688,7 +3692,7 @@ method_call	: fcall paren_args
 			$$ = dispatch3(call, $1, ID2SYM(idCOLON2), $3);
 		    %*/
 		    }
-		| primary_value '.'
+		| primary_value call_op
 		    {
 		    /*%%%*/
 			$<num>$ = ruby_sourceline;
@@ -3697,10 +3701,10 @@ method_call	: fcall paren_args
 		  paren_args
 		    {
 		    /*%%%*/
-			$$ = NEW_CALL($1, idCall, $4);
+			$$ = NEW_QCALL($2, $1, idCall, $4);
 			nd_set_line($$, $<num>3);
 		    /*%
-			$$ = dispatch3(call, $1, ripper_id2sym('.'),
+			$$ = dispatch3(call, $1, ripper_id2sym($2),
 				       ID2SYM(idCall));
 			$$ = method_optarg($$, $4);
 		    %*/
@@ -5103,7 +5107,7 @@ operation3	: tIDENTIFIER
 		| op
 		;
 
-dot_or_colon	: '.'
+dot_or_colon	: call_op
 		    /*%c%*/
 		    /*%c
 		    { $$ = $<val>1; }
@@ -5115,6 +5119,10 @@ dot_or_colon	: '.'
 		    %*/
 		;
 
+call_op 	: '.' {$$ = '.';}
+		| tDOTQ {$$ = tDOTQ;}
+		;
+
 opt_terms	: /* none */
 		| terms
 		;
@@ -8356,6 +8364,10 @@ parser_yylex(struct parser_params *parser)
 	    pushback(c);
 	    return tDOT2;
 	}
+	if (c == '?') {
+	    lex_state = EXPR_DOT;
+	    return tDOTQ;
+	}
 	pushback(c);
 	if (c != -1 && ISDIGIT(c)) {
 	    yyerror("no .<digit> floating literal anymore; put 0 before dot");
@@ -10036,7 +10048,8 @@ new_op_assign_gen(struct parser_params *parser, NODE *lhs, ID op, NODE *rhs)
 }
 
 static NODE *
-new_attr_op_assign_gen(struct parser_params *parser, NODE *lhs, ID attr, ID op, NODE *rhs)
+new_attr_op_assign_gen(struct parser_params *parser, NODE *lhs,
+		       ID atype, ID attr, ID op, NODE *rhs)
 {
     NODE *asgn;
 
@@ -10046,7 +10059,7 @@ new_attr_op_assign_gen(struct parser_params *parser, NODE *lhs, ID attr, ID op,
     else if (op == tANDOP) {
 	op = 1;
     }
-    asgn = NEW_OP_ASGN2(lhs, attr, op, rhs);
+    asgn = NEW_OP_ASGN2(lhs, (atype == tDOTQ), attr, op, rhs);
     fixpos(asgn, lhs);
     return asgn;
 }