Add a 32-bit x86_64 arch variant

In make, the current 32-bit configuration for generic x86_64 targets
inherits some variables (SSE4 support) from the 64-bit configuration,
and overrides the make variables used for other configurations (SSSE3).

We don't have that problem in Soong, but this is the configuration
matching what Make is using.

Change-Id: Ia934ff40f9388f9c202a0fe0608e7b45b77a2714

cc/x86_device.go

@@ -73,6 +73,9 @@ var (
 		"": []string{
 			"-march=prescott",
 		},
+		"x86_64": []string{
+			"-march=prescott",
+		},
 		"atom": []string{
 			"-march=atom",
 			"-mfpmath=sse",
@@ -110,6 +113,12 @@ const (
 )
 
 func init() {
+	common.RegisterArchFeatures(common.X86, "x86_64",
+		"ssse3",
+		"sse4",
+		"sse4_1",
+		"sse4_2",
+		"popcnt")
 	common.RegisterArchFeatures(common.X86, "atom",
 		"ssse3",
 		"movbe")

common/arch.go

@@ -186,6 +186,8 @@ type archProperties struct {
 			Ivybridge   interface{} `blueprint:"filter(android:\"arch_variant\")"`
 			Sandybridge interface{} `blueprint:"filter(android:\"arch_variant\")"`
 			Silvermont  interface{} `blueprint:"filter(android:\"arch_variant\")"`
+			// Generic variant for X86 on X86_64
+			X86_64      interface{} `blueprint:"filter(android:\"arch_variant\")"`
 
 			// X86 arch features
 			Ssse3  interface{} `blueprint:"filter(android:\"arch_variant\")"`
@@ -955,6 +957,7 @@ func decodeMegaDevice() ([]Arch, error) {
 		{"x86", "ivybridge", "", []string{"x86"}},
 		{"x86", "sandybridge", "", []string{"x86"}},
 		{"x86", "silvermont", "", []string{"x86"}},
+		{"x86", "x86_64", "", []string{"x86"}},
 		{"x86_64", "", "", []string{"x86_64"}},
 		{"x86_64", "haswell", "", []string{"x86_64"}},
 		{"x86_64", "ivybridge", "", []string{"x86_64"}},