[SourceKit] Don't build an AST if no semantic info is requested

Currently, we were building an AST on document open or edit even if
- `key_enablesyntaxmap` = 0
- `key_enablesubstructure` = 0
- `key_enablediagnostics` = 0 and
- syntax tree transfer mode is off

In those cases we were just ignoring the result.

If all of the options are 0, don’t build an AST.

rdar://85847659

Author: ahoppen

test/SourceKit/CodeExpand/code-expand-rdar77665805.swift

@@ -6,7 +6,7 @@ func test() {
 
 // RUN: %sourcekitd-test \
 // RUN:   -req=open %s -- %s == \
-// RUN:   -req=edit -offset=0 -length=53 -replace="" -req-opts=enablesyntaxmap=0,enablesubstructure=0,enablediagnostics=0 %s -- %s == \
+// RUN:   -req=edit -offset=0 -length=53 -replace="" -req-opts=enablesyntaxmap=0,enablesubstructure=0,enablediagnostics=0 -dont-print-response %s -- %s == \
 // RUN:   -req=expand-placeholder -offset=23 -length=18 %s \
 // RUN: | %FileCheck %s
 

test/SourceKit/CursorInfo/cursor_after_edit.swift

@@ -7,5 +7,5 @@
 // buffer to calculate line and column (before rdar://78161348).
 // RUN: %sourcekitd-test \
 // RUN:   -req=open -text-input %t/empty.swift %t/func.swift -- %t/func.swift == \
-// RUN:   -req=edit -offset=0 -length=0 -replace="func foo() {}" -req-opts=enablesyntaxmap=0,enablesubstructure=0,enablediagnostics=0 %t/func.swift -- %t/func.swift == \
+// RUN:   -req=edit -offset=0 -length=0 -replace="func foo() {}" -req-opts=enablesyntaxmap=0,enablesubstructure=0,enablediagnostics=0 -dont-print-response %t/func.swift -- %t/func.swift == \
 // RUN:   -req=cursor -offset=5 %t/func.swift -- %t/func.swift

test/SourceKit/Sema/edit_nowait.swift

@@ -15,10 +15,10 @@
 // EDIT_NOWAIT-NEXT: }
 
 // RUN: %sourcekitd-test \
-// RUN:   -req=open -req-opts=enablesyntaxmap=0,enablesubstructure=0,enablediagnostics=0 %t/t.swift -- %t/t.swift == \
+// RUN:   -req=open -req-opts=enablesyntaxmap=0,enablesubstructure=1,enablediagnostics=0 %t/t.swift -- %t/t.swift == \
 // RUN:   -req=print-annotations %t/t.swift  == \
-// RUN:   -req=edit -offset=0 -replace="func foo() { warn("") }" -length=16 -req-opts=enablesyntaxmap=0,enablesubstructure=0,enablediagnostics=0 %t/t.swift == \
-// RUN:   -req=edit -offset=13 -replace="print" -length=4 -req-opts=enablesyntaxmap=0,enablesubstructure=0,enablediagnostics=0 %t/t.swift == \
+// RUN:   -req=edit -offset=0 -replace="func foo() { warn("") }" -length=16 -req-opts=enablesyntaxmap=0,enablesubstructure=1,enablediagnostics=0 %t/t.swift == \
+// RUN:   -req=edit -offset=13 -replace="print" -length=4 -req-opts=enablesyntaxmap=0,enablesubstructure=1,enablediagnostics=0 %t/t.swift == \
 // RUN:   -req=print-annotations %t/t.swift \
 // RUN: | %FileCheck --check-prefix=ANNOTATION %s
 

tools/SourceKit/tools/sourcekitd/lib/API/Requests.cpp

@@ -2663,7 +2663,18 @@ class SKEditorConsumer : public EditorConsumer {
   sourcekitd_response_t createResponse();
 
   bool needsSemanticInfo() override {
-    return !Opts.SyntacticOnly && !isSemanticEditorDisabled();
+    if (Opts.SyntacticOnly) {
+      return false;
+    } else if (isSemanticEditorDisabled()) {
+      return false;
+    } else if (!documentStructureEnabled() &&
+               !syntaxMapEnabled() &&
+               !diagnosticsEnabled() &&
+               !syntaxTreeEnabled()) {
+      return false;
+    } else {
+      return true;
+    }
   }
 
   void handleRequestError(const char *Description) override;