From d12afec49c18e99ad2755e8a123feb1efcbfb409 Mon Sep 17 00:00:00 2001
From: Dan Albert <danalbert@google.com>
Date: Fri, 14 Aug 2020 16:53:21 -0700
Subject: [PATCH] Allow globally disabling some clang-tidy checks.

Test: used for the upcoming compiler update
Bug: None
Change-Id: Id17db2c48fa3e165da81a1d084827bde142406dd
---
 cc/config/clang.go | 42 +++++++++++++++++++++++++++++-------------
 cc/tidy.go         |  3 ++-
 2 files changed, 31 insertions(+), 14 deletions(-)

diff --git a/cc/config/clang.go b/cc/config/clang.go
index 24dc6b932..7db405c2e 100644
--- a/cc/config/clang.go
+++ b/cc/config/clang.go
@@ -15,6 +15,7 @@
 package config
 
 import (
+	"android/soong/android"
 	"sort"
 	"strings"
 )
@@ -88,6 +89,12 @@ var ClangUnknownLldflags = sorted([]string{
 
 var ClangLibToolingUnknownCflags = sorted([]string{})
 
+// List of tidy checks that should be disabled globally. When the compiler is
+// updated, some checks enabled by this module may be disabled if they have
+// become more strict, or if they are a new match for a wildcard group like
+// `modernize-*`.
+var ClangTidyDisableChecks = []string{}
+
 func init() {
 	pctx.StaticVariable("ClangExtraCflags", strings.Join([]string{
 		"-D__compiler_offsetof=__builtin_offsetof",
@@ -202,25 +209,34 @@ func init() {
 }
 
 func ClangFilterUnknownCflags(cflags []string) []string {
-	ret := make([]string, 0, len(cflags))
-	for _, f := range cflags {
-		if !inListSorted(f, ClangUnknownCflags) {
-			ret = append(ret, f)
+	result, _ := android.FilterList(cflags, ClangUnknownCflags)
+	return result
+}
+
+func clangTidyNegateChecks(checks []string) []string {
+	ret := make([]string, 0, len(checks))
+	for _, c := range checks {
+		if strings.HasPrefix(c, "-") {
+			ret = append(ret, c)
+		} else {
+			ret = append(ret, "-"+c)
 		}
 	}
-
 	return ret
 }
 
-func ClangFilterUnknownLldflags(lldflags []string) []string {
-	ret := make([]string, 0, len(lldflags))
-	for _, f := range lldflags {
-		if !inListSorted(f, ClangUnknownLldflags) {
-			ret = append(ret, f)
-		}
-	}
+func ClangRewriteTidyChecks(checks []string) []string {
+	checks = append(checks, clangTidyNegateChecks(ClangTidyDisableChecks)...)
+	// clang-tidy does not allow later arguments to override earlier arguments,
+	// so if we just disabled an argument that was explicitly enabled we must
+	// remove the enabling argument from the list.
+	result, _ := android.FilterList(checks, ClangTidyDisableChecks)
+	return result
+}
 
-	return ret
+func ClangFilterUnknownLldflags(lldflags []string) []string {
+	result, _ := android.FilterList(lldflags, ClangUnknownLldflags)
+	return result
 }
 
 func inListSorted(s string, list []string) bool {
diff --git a/cc/tidy.go b/cc/tidy.go
index 364e56c5d..17471e674 100644
--- a/cc/tidy.go
+++ b/cc/tidy.go
@@ -109,7 +109,8 @@ func (tidy *tidyFeature) flags(ctx ModuleContext, flags Flags) Flags {
 		tidyChecks += config.TidyChecksForDir(ctx.ModuleDir())
 	}
 	if len(tidy.Properties.Tidy_checks) > 0 {
-		tidyChecks = tidyChecks + "," + strings.Join(esc(tidy.Properties.Tidy_checks), ",")
+		tidyChecks = tidyChecks + "," + strings.Join(esc(
+			config.ClangRewriteTidyChecks(tidy.Properties.Tidy_checks)), ",")
 	}
 	if ctx.Windows() {
 		// https://b.corp.google.com/issues/120614316