[PRISM] Implement safe navigation in CallNodes

This commit implements safe navigation for CallNodes,
CallAndWriteNodes and CallOperatorWriteNodes

prism_compile.c

@@ -855,9 +855,10 @@ pm_compile_class_path(LINK_ANCHOR *const ret, rb_iseq_t *iseq, const pm_node_t *
 }
 
 static void
-pm_compile_call_and_or_write_node(bool and_node, pm_node_t *receiver, pm_node_t *value, pm_constant_id_t write_name, pm_constant_id_t read_name, LINK_ANCHOR *const ret, rb_iseq_t *iseq, int lineno, const uint8_t * src, bool popped, pm_scope_node_t *scope_node)
+pm_compile_call_and_or_write_node(bool and_node, pm_node_t *receiver, pm_node_t *value, pm_constant_id_t write_name, pm_constant_id_t read_name, bool safe_nav, LINK_ANCHOR *const ret, rb_iseq_t *iseq, int lineno, const uint8_t * src, bool popped, pm_scope_node_t *scope_node)
 {
     LABEL *call_end_label = NEW_LABEL(lineno);
+    LABEL *else_label = NEW_LABEL(lineno);
     LABEL *end_label = NEW_LABEL(lineno);
     NODE dummy_line_node = generate_dummy_line_node(lineno, lineno);
 
@@ -869,6 +870,11 @@ pm_compile_call_and_or_write_node(bool and_node, pm_node_t *receiver, pm_node_t
 
     PM_COMPILE_NOT_POPPED(receiver);
 
+    if (safe_nav) {
+        PM_DUP;
+        ADD_INSNL(ret, &dummy_line_node, branchnil, else_label);
+    }
+
     ID write_name_id = pm_constant_id_lookup(scope_node, write_name);
     ID read_name_id = pm_constant_id_lookup(scope_node, read_name);
     PM_DUP;
@@ -901,6 +907,10 @@ pm_compile_call_and_or_write_node(bool and_node, pm_node_t *receiver, pm_node_t
         PM_SWAP;
     }
 
+    if (safe_nav) {
+        ADD_LABEL(ret, else_label);
+    }
+
     ADD_LABEL(ret, end_label);
     PM_POP;
     return;
@@ -2565,10 +2575,16 @@ pm_compile_call(rb_iseq_t *iseq, const pm_call_node_t *call_node, LINK_ANCHOR *c
     pm_newline_list_t newline_list = parser->newline_list;
     int lineno = (int)pm_newline_list_line_column(&newline_list, ((pm_node_t *)call_node)->location.start).line;
     NODE dummy_line_node = generate_dummy_line_node(lineno, lineno);
-    LABEL *end = NEW_LABEL(lineno);
+    LABEL *else_label = NEW_LABEL(lineno);
+    LABEL *end_label = NEW_LABEL(lineno);
 
     pm_node_t *pm_node = (pm_node_t *)call_node;
 
+    if (call_node->base.flags & PM_CALL_NODE_FLAGS_SAFE_NAVIGATION) {
+        PM_DUP;
+        ADD_INSNL(ret, &dummy_line_node, branchnil, else_label);
+    }
+
     int flags = 0;
     struct rb_callinfo_kwarg *kw_arg = NULL;
 
@@ -2582,7 +2598,7 @@ pm_compile_call(rb_iseq_t *iseq, const pm_call_node_t *call_node, LINK_ANCHOR *c
 
         block_iseq = NEW_CHILD_ISEQ(next_scope_node, make_name_for_block(iseq), ISEQ_TYPE_BLOCK, lineno);
         if (ISEQ_BODY(block_iseq)->catch_table) {
-            ADD_CATCH_ENTRY(CATCH_TYPE_BREAK, start, end, block_iseq, end);
+            ADD_CATCH_ENTRY(CATCH_TYPE_BREAK, start, end_label, block_iseq, end_label);
         }
         ISEQ_COMPILE_DATA(iseq)->current_block = block_iseq;
     }
@@ -2613,7 +2629,12 @@ pm_compile_call(rb_iseq_t *iseq, const pm_call_node_t *call_node, LINK_ANCHOR *c
     else {
         ADD_SEND_R(ret, &dummy_line_node, method_id, INT2FIX(orig_argc), block_iseq, INT2FIX(flags), kw_arg);
     }
-    ADD_LABEL(ret, end);
+
+    if (call_node->base.flags & PM_CALL_NODE_FLAGS_SAFE_NAVIGATION) {
+        ADD_INSNL(ret, &dummy_line_node, jump, end_label);
+        ADD_LABEL(ret, else_label);
+    }
+    ADD_LABEL(ret, end_label);
 
     PM_POP_IF_POPPED;
 }
@@ -3131,14 +3152,17 @@ pm_compile_node(rb_iseq_t *iseq, const pm_node_t *node, LINK_ANCHOR *const ret,
       case PM_CALL_AND_WRITE_NODE: {
         pm_call_and_write_node_t *call_and_write_node = (pm_call_and_write_node_t*) node;
 
-        pm_compile_call_and_or_write_node(true, call_and_write_node->receiver, call_and_write_node->value, call_and_write_node->write_name, call_and_write_node->read_name, ret, iseq, lineno, src, popped, scope_node);
+        bool safe_nav = node->flags & PM_CALL_NODE_FLAGS_SAFE_NAVIGATION;
+
+        pm_compile_call_and_or_write_node(true, call_and_write_node->receiver, call_and_write_node->value, call_and_write_node->write_name, call_and_write_node->read_name, safe_nav, ret, iseq, lineno, src, popped, scope_node);
 
         return;
       }
       case PM_CALL_OR_WRITE_NODE: {
         pm_call_or_write_node_t *call_or_write_node = (pm_call_or_write_node_t*) node;
+        bool safe_nav = node->flags & PM_CALL_NODE_FLAGS_SAFE_NAVIGATION;
 
-        pm_compile_call_and_or_write_node(false, call_or_write_node->receiver, call_or_write_node->value, call_or_write_node->write_name, call_or_write_node->read_name, ret, iseq, lineno, src, popped, scope_node);
+        pm_compile_call_and_or_write_node(false, call_or_write_node->receiver, call_or_write_node->value, call_or_write_node->write_name, call_or_write_node->read_name, safe_nav, ret, iseq, lineno, src, popped, scope_node);
 
         return;
       }

test/ruby/test_compile_prism.rb

@@ -1470,6 +1470,16 @@ module Prism
         pm = PrivateMethod.new
         pm.send(:instance_var)
       CODE
+
+      # Testing safe navigation operator
+      assert_prism_eval(<<-CODE)
+        def self.test_prism_call_node
+          if [][0]&.first
+            1
+          end
+        end
+        test_prism_call_node
+      CODE
     end
 
     def test_CallAndWriteNode
@@ -1507,6 +1517,24 @@ module Prism
         self.test_call_and_write_node &&= 1
       CODE
       )
+
+      assert_prism_eval(<<-CODE)
+        def self.test_prism_call_node; end
+        def self.test_prism_call_node=(val)
+          val
+        end
+        self&.test_prism_call_node &&= 1
+      CODE
+
+      assert_prism_eval(<<-CODE)
+        def self.test_prism_call_node
+          2
+        end
+        def self.test_prism_call_node=(val)
+          val
+        end
+        self&.test_prism_call_node &&= 1
+      CODE
     end
 
     def test_CallOrWriteNode
@@ -1544,6 +1572,24 @@ module Prism
         self.test_call_or_write_node ||= 1
       CODE
       )
+
+      assert_prism_eval(<<-CODE)
+        def self.test_prism_call_node
+          2
+        end
+        def self.test_prism_call_node=(val)
+          val
+        end
+        self&.test_prism_call_node ||= 1
+      CODE
+
+      assert_prism_eval(<<-CODE)
+        def self.test_prism_call_node; end
+        def self.test_prism_call_node=(val)
+          val
+        end
+        self&.test_prism_call_node ||= 1
+      CODE
     end
 
     def test_CallOperatorWriteNode