internal/lsp: add options to control which details gc_details shows

The gc_details command, which shows the gc compiler's decisions, can
produce thousands of diagnostics for a package. New gopls options
'noBounds', 'noEscape', 'noInline', 'noNilcheck' will suppress diagnostics
of less interest to the user. These are in a new 'annotations' section
parallel to 'codelens' or 'analyses'.

Change-Id: Ica75de25b14f38b67ddfa9f997f581674f45221d
Reviewed-on: https://go-review.googlesource.com/c/tools/+/246477
Run-TryBot: Peter Weinberger <pjw@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>

gopls/doc/settings.md

@@ -147,10 +147,6 @@ If true, this enables server side fuzzy matching of completion candidates.
 
 Default: `true`.
 
-### **staticcheck** *boolean*
-
-If true, it enables the use of the staticcheck.io analyzers.
-
 ### **matcher** *string*
 
 Defines the algorithm that is used when calculating completion candidates. Must be one of:
@@ -159,7 +155,21 @@ Defines the algorithm that is used when calculating completion candidates. Must
 * `"caseSensitive"`
 * `"caseInsensitive"`
 
-Default: `"caseInsensitive"`.
+Default: `"caseInsensitive"`
+
+### **annotations** *map[string]bool*
+
+**noBounds** suppresses gc_details diagnostics about bounds checking.
+
+**noEscape** suppresses gc_details diagnostics about escape analysis.
+
+**noInline** suppresses gc_details diagnostics about inlining.
+
+**noNilcheck** suppresses gc_details diagnostics about generated nil checks.
+
+### **staticcheck** *boolean*
+
+If true, it enables the use of the staticcheck.io analyzers.
 
 ### **symbolMatcher** *string*
 

internal/lsp/source/gc_annotations.go

@@ -33,6 +33,7 @@ func GCOptimizationDetails(ctx context.Context, snapshot Snapshot, pkgDir span.U
 		return nil, err
 	}
 	reports := make(map[VersionedFileIdentity][]*Diagnostic)
+	opts := snapshot.View().Options()
 	var parseError error
 	for _, fn := range files {
 		fname, v, err := parseDetailsFile(fn)
@@ -48,11 +49,38 @@ func GCOptimizationDetails(ctx context.Context, snapshot Snapshot, pkgDir span.U
 		if x == nil {
 			continue
 		}
+		v = filterDiagnostics(v, &opts)
 		reports[x.VersionedFileIdentity()] = v
 	}
 	return reports, parseError
 }
 
+func filterDiagnostics(v []*Diagnostic, o *Options) []*Diagnostic {
+	var ans []*Diagnostic
+	for _, x := range v {
+		if x.Source != "go compiler" {
+			continue
+		}
+		if o.Annotations["noInline"] &&
+			(strings.HasPrefix(x.Message, "canInline") ||
+				strings.HasPrefix(x.Message, "cannotInline") ||
+				strings.HasPrefix(x.Message, "inlineCall")) {
+			continue
+		} else if o.Annotations["noEscape"] &&
+			(strings.HasPrefix(x.Message, "escape") || x.Message == "leak") {
+			continue
+		} else if o.Annotations["noNilcheck"] && strings.HasPrefix(x.Message, "nilcheck") {
+			continue
+		} else if o.Annotations["noBounds"] &&
+			(strings.HasPrefix(x.Message, "isInBounds") ||
+				strings.HasPrefix(x.Message, "isSliceInBounds")) {
+			continue
+		}
+		ans = append(ans, x)
+	}
+	return ans
+}
+
 func parseDetailsFile(fn string) (string, []*Diagnostic, error) {
 	buf, err := ioutil.ReadFile(fn)
 	if err != nil {

internal/lsp/source/options.go

@@ -281,6 +281,14 @@ type ExperimentalOptions struct {
 	// VerboseWorkDoneProgress controls whether the LSP server should send
 	// progress reports for all work done outside the scope of an RPC.
 	VerboseWorkDoneProgress bool
+
+	// Annotations suppress various kinds of optimization diagnostics
+	// that would be reported by the gc_details command.
+	//   noNilcheck suppresses display of nilchecks.
+	//   noEscape suppresses escape choices.
+	//   noInline suppresses inlining choices.
+	//   noBounds suppresses bounds checking diagnositcs.
+	Annotations map[string]bool
 }
 
 // DebuggingOptions should not affect the logical execution of Gopls, but may
@@ -526,6 +534,18 @@ func (o *Options) set(name string, value interface{}) OptionResult {
 	case "analyses":
 		result.setBoolMap(&o.UserEnabledAnalyses)
 
+	case "annotations":
+		result.setBoolMap(&o.Annotations)
+		for k := range o.Annotations {
+			switch k {
+			case "noEscape", "noNilcheck", "noInline", "noBounds":
+				continue
+			default:
+				result.Name += ":" + k // put mistake(s) in the message
+				result.State = OptionUnexpected
+			}
+		}
+
 	case "codelens":
 		var lensOverrides map[string]bool
 		result.setBoolMap(&lensOverrides)