Generate tidy-* rules unless tidy is disabled

* make tidy-soong_subset, or make tidy-<any_directory>,
  should trigger the same clang-tidy compilations
  with or without global WITH_TIDY=1.
* Normal make should not trigger clang-tidy compilations
  unless global WITH_TIDY=1 or a module has set tidy:true.

Bug: 213918926
Test: NINJA_ARGS="-n" make tidy-soong_subset
Test: NINJA_ARGS="-n" make <some-library>
Change-Id: Iafffd3894abe137c9584c2c01830898422f9a677

cc/cc.go

@@ -210,11 +210,12 @@ type Flags struct {
 	// These must be after any module include flags, which will be in CommonFlags.
 	SystemIncludeFlags []string
 
-	Toolchain    config.Toolchain
-	Tidy         bool // True if clang-tidy is enabled.
-	GcovCoverage bool // True if coverage files should be generated.
-	SAbiDump     bool // True if header abi dumps should be generated.
-	EmitXrefs    bool // If true, generate Ninja rules to generate emitXrefs input files for Kythe
+	Toolchain     config.Toolchain
+	Tidy          bool // True if ninja .tidy rules should be generated.
+	NeedTidyFiles bool // True if module link should depend on .tidy files
+	GcovCoverage  bool // True if coverage files should be generated.
+	SAbiDump      bool // True if header abi dumps should be generated.
+	EmitXrefs     bool // If true, generate Ninja rules to generate emitXrefs input files for Kythe
 
 	// The instruction set required for clang ("arm" or "thumb").
 	RequiredInstructionSet string
@@ -516,6 +517,12 @@ type ModuleContextIntf interface {
 	directlyInAnyApex() bool
 	isPreventInstall() bool
 	isCfiAssemblySupportEnabled() bool
+	getSharedFlags() *SharedFlags
+}
+
+type SharedFlags struct {
+	numSharedFlags int
+	flagsMap       map[string]string
 }
 
 type ModuleContext interface {
@@ -827,6 +834,9 @@ type Module struct {
 	// Flags used to compile this module
 	flags Flags
 
+	// Shared flags among build rules of this module
+	sharedFlags SharedFlags
+
 	// only non-nil when this is a shared library that reuses the objects of a static library
 	staticAnalogue *StaticLibraryInfo
 
@@ -1605,6 +1615,15 @@ func (ctx *moduleContextImpl) isPreventInstall() bool {
 	return ctx.mod.Properties.PreventInstall
 }
 
+func (ctx *moduleContextImpl) getSharedFlags() *SharedFlags {
+	shared := &ctx.mod.sharedFlags
+	if shared.flagsMap == nil {
+		shared.numSharedFlags = 0
+		shared.flagsMap = make(map[string]string)
+	}
+	return shared
+}
+
 func (ctx *moduleContextImpl) isCfiAssemblySupportEnabled() bool {
 	return ctx.mod.isCfiAssemblySupportEnabled()
 }