Propagate empty vs unspecified system_shared_libs correctly.

Necessary to get correct prebuilts for many Bionic libs.

Cleaned up numerious "system_shared_libs: []" from test fixtures, since
they otherwise would need correction in the expected results, and it is
better to have a single test focused on testing system_shared_libs
propagation.

Test: m nothing
Bug: 152255951
Change-Id: If2e8a5296223e6281d833312660e8e9e4cd184c0

cc/binary_sdk_member.go

@@ -18,6 +18,7 @@ import (
 	"path/filepath"
 
 	"android/soong/android"
+
 	"github.com/google/blueprint"
 )
 
@@ -137,7 +138,9 @@ func (p *nativeBinaryInfoProperties) AddToPropertySet(ctx android.SdkMemberConte
 		propertySet.AddPropertyWithTag("shared_libs", p.SharedLibs, builder.SdkMemberReferencePropertyTag(false))
 	}
 
-	if len(p.SystemSharedLibs) > 0 {
+	// SystemSharedLibs needs to be propagated if it's a list, even if it's empty,
+	// so check for non-nil instead of nonzero length.
+	if p.SystemSharedLibs != nil {
 		propertySet.AddPropertyWithTag("system_shared_libs", p.SystemSharedLibs, builder.SdkMemberReferencePropertyTag(false))
 	}
 }

cc/cc.go

@@ -378,7 +378,7 @@ type linker interface {
 
 type specifiedDeps struct {
 	sharedLibs       []string
-	systemSharedLibs []string
+	systemSharedLibs []string // Note nil and [] are semantically distinct.
 }
 
 type installer interface {

cc/library.go

@@ -749,10 +749,12 @@ func (library *libraryDecorator) compilerDeps(ctx DepsContext, deps Deps) Deps {
 
 func (library *libraryDecorator) linkerDeps(ctx DepsContext, deps Deps) Deps {
 	if library.static() {
+		// Compare with nil because an empty list needs to be propagated.
 		if library.StaticProperties.Static.System_shared_libs != nil {
 			library.baseLinker.Properties.System_shared_libs = library.StaticProperties.Static.System_shared_libs
 		}
 	} else if library.shared() {
+		// Compare with nil because an empty list needs to be propagated.
 		if library.SharedProperties.Shared.System_shared_libs != nil {
 			library.baseLinker.Properties.System_shared_libs = library.SharedProperties.Shared.System_shared_libs
 		}
@@ -828,10 +830,21 @@ func (library *libraryDecorator) linkerSpecifiedDeps(specifiedDeps specifiedDeps
 	}
 
 	specifiedDeps.sharedLibs = append(specifiedDeps.sharedLibs, properties.Shared_libs...)
+
+	// Must distinguish nil and [] in system_shared_libs - ensure that [] in
+	// either input list doesn't come out as nil.
+	if specifiedDeps.systemSharedLibs == nil {
+		specifiedDeps.systemSharedLibs = properties.System_shared_libs
+	} else {
 		specifiedDeps.systemSharedLibs = append(specifiedDeps.systemSharedLibs, properties.System_shared_libs...)
+	}
 
 	specifiedDeps.sharedLibs = android.FirstUniqueStrings(specifiedDeps.sharedLibs)
+	if len(specifiedDeps.systemSharedLibs) > 0 {
+		// Skip this if systemSharedLibs is either nil or [], to ensure they are
+		// retained.
 		specifiedDeps.systemSharedLibs = android.FirstUniqueStrings(specifiedDeps.systemSharedLibs)
+	}
 	return specifiedDeps
 }
 
@@ -1371,6 +1384,8 @@ func reuseStaticLibrary(mctx android.BottomUpMutatorContext, static, shared *Mod
 			len(sharedCompiler.SharedProperties.Shared.Static_libs) == 0 &&
 			len(staticCompiler.StaticProperties.Static.Shared_libs) == 0 &&
 			len(sharedCompiler.SharedProperties.Shared.Shared_libs) == 0 &&
+			// Compare System_shared_libs properties with nil because empty lists are
+			// semantically significant for them.
 			staticCompiler.StaticProperties.Static.System_shared_libs == nil &&
 			sharedCompiler.SharedProperties.Shared.System_shared_libs == nil {
 

cc/library_sdk_member.go

@@ -212,7 +212,9 @@ func addPossiblyArchSpecificProperties(sdkModuleContext android.ModuleContext, b
 		outputProperties.AddPropertyWithTag("shared_libs", libInfo.SharedLibs, builder.SdkMemberReferencePropertyTag(false))
 	}
 
-	if len(libInfo.SystemSharedLibs) > 0 {
+	// SystemSharedLibs needs to be propagated if it's a list, even if it's empty,
+	// so check for non-nil instead of nonzero length.
+	if libInfo.SystemSharedLibs != nil {
 		outputProperties.AddPropertyWithTag("system_shared_libs", libInfo.SystemSharedLibs, builder.SdkMemberReferencePropertyTag(false))
 	}
 
@@ -327,7 +329,8 @@ type nativeLibInfoProperties struct {
 	// This field is exported as its contents may not be arch specific.
 	SharedLibs []string
 
-	// The set of system shared libraries
+	// The set of system shared libraries. Note nil and [] are semantically
+	// distinct - see BaseLinkerProperties.System_shared_libs.
 	//
 	// This field is exported as its contents may not be arch specific.
 	SystemSharedLibs []string

cc/linker.go

@@ -491,7 +491,15 @@ func (linker *baseLinker) link(ctx ModuleContext,
 
 func (linker *baseLinker) linkerSpecifiedDeps(specifiedDeps specifiedDeps) specifiedDeps {
 	specifiedDeps.sharedLibs = append(specifiedDeps.sharedLibs, linker.Properties.Shared_libs...)
+
+	// Must distinguish nil and [] in system_shared_libs - ensure that [] in
+	// either input list doesn't come out as nil.
+	if specifiedDeps.systemSharedLibs == nil {
+		specifiedDeps.systemSharedLibs = linker.Properties.System_shared_libs
+	} else {
 		specifiedDeps.systemSharedLibs = append(specifiedDeps.systemSharedLibs, linker.Properties.System_shared_libs...)
+	}
+
 	return specifiedDeps
 }
 

sdk/cc_sdk_test.go

@@ -48,7 +48,6 @@ func TestSdkIsCompileMultilibBoth(t *testing.T) {
 		cc_library_shared {
 			name: "sdkmember",
 			srcs: ["Test.cpp"],
-			system_shared_libs: [],
 			stl: "none",
 		}
 	`)
@@ -178,13 +177,11 @@ func TestHostSdkWithCc(t *testing.T) {
 
 		cc_library_host_shared {
 			name: "sdkshared",
-			system_shared_libs: [],
 			stl: "none",
 		}
 
 		cc_library_host_static {
 			name: "sdkstatic",
-			system_shared_libs: [],
 			stl: "none",
 		}
 	`)
@@ -201,25 +198,21 @@ func TestSdkWithCc(t *testing.T) {
 
 		cc_library_shared {
 			name: "sdkshared",
-			system_shared_libs: [],
 			stl: "none",
 		}
 
 		cc_library_static {
 			name: "sdkstatic",
-			system_shared_libs: [],
 			stl: "none",
 		}
 
 		cc_library {
 			name: "sdkboth1",
-			system_shared_libs: [],
 			stl: "none",
 		}
 
 		cc_library {
 			name: "sdkboth2",
-			system_shared_libs: [],
 			stl: "none",
 		}
 	`)
@@ -295,7 +288,6 @@ func TestSnapshotWithCcDuplicateHeaders(t *testing.T) {
 				"Test.cpp",
 			],
 			export_include_dirs: ["include"],
-			system_shared_libs: [],
 			stl: "none",
 		}
 
@@ -305,7 +297,6 @@ func TestSnapshotWithCcDuplicateHeaders(t *testing.T) {
 				"Test.cpp",
 			],
 			export_include_dirs: ["include"],
-			system_shared_libs: [],
 			stl: "none",
 		}
 	`)
@@ -342,7 +333,6 @@ func TestSnapshotWithCcSharedLibraryCommonProperties(t *testing.T) {
 					export_system_include_dirs: ["arm64/include"],
 				},
 			},
-			system_shared_libs: [],
 			stl: "none",
 		}
 	`)
@@ -410,7 +400,6 @@ func TestSnapshotWithCcBinary(t *testing.T) {
 				"Test.cpp",
 			],
 			compile_multilib: "both",
-			system_shared_libs: [],
 			stl: "none",
 		}
 	`)
@@ -485,7 +474,6 @@ func TestMultipleHostOsTypesSnapshotWithCcBinary(t *testing.T) {
 				"Test.cpp",
 			],
 			compile_multilib: "both",
-			system_shared_libs: [],
 			stl: "none",
 			target: {
 				windows: {
@@ -586,7 +574,6 @@ func TestSnapshotWithCcSharedLibrary(t *testing.T) {
 			aidl: {
 				export_aidl_headers: true,
 			},
-			system_shared_libs: [],
 			stl: "none",
 		}
 	`)
@@ -673,7 +660,6 @@ func TestSnapshotWithCcSharedLibrarySharedLibs(t *testing.T) {
 			srcs: [
 				"Test.cpp",
 			],
-			system_shared_libs: [],
 			stl: "none",
 		}
 
@@ -714,7 +700,6 @@ func TestSnapshotWithCcSharedLibrarySharedLibs(t *testing.T) {
 					},
 				},
 			},
-			system_shared_libs: [],
 			stl: "none",
 		}
 	`)
@@ -864,7 +849,6 @@ func TestHostSnapshotWithCcSharedLibrary(t *testing.T) {
 			aidl: {
 				export_aidl_headers: true,
 			},
-			system_shared_libs: [],
 			stl: "none",
 			sdk_version: "minimum",
 		}
@@ -960,7 +944,6 @@ func TestMultipleHostOsTypesSnapshotWithCcSharedLibrary(t *testing.T) {
 			srcs: [
 				"Test.cpp",
 			],
-			system_shared_libs: [],
 			stl: "none",
 			target: {
 				windows: {
@@ -1050,7 +1033,6 @@ func TestSnapshotWithCcStaticLibrary(t *testing.T) {
 			aidl: {
 				export_aidl_headers: true,
 			},
-			system_shared_libs: [],
 			stl: "none",
 		}
 	`)
@@ -1137,7 +1119,6 @@ func TestHostSnapshotWithCcStaticLibrary(t *testing.T) {
 			aidl: {
 				export_aidl_headers: true,
 			},
-			system_shared_libs: [],
 			stl: "none",
 		}
 	`)
@@ -1219,7 +1200,6 @@ func TestSnapshotWithCcLibrary(t *testing.T) {
 				"Test.cpp",
 			],
 			export_include_dirs: ["include"],
-			system_shared_libs: [],
 			stl: "none",
 		}
 	`)
@@ -1322,7 +1302,6 @@ func TestHostSnapshotWithMultiLib64(t *testing.T) {
 			aidl: {
 				export_aidl_headers: true,
 			},
-			system_shared_libs: [],
 			stl: "none",
 		}
 	`)
@@ -1393,7 +1372,6 @@ func TestSnapshotWithCcHeadersLibrary(t *testing.T) {
 		cc_library_headers {
 			name: "mynativeheaders",
 			export_include_dirs: ["include"],
-			system_shared_libs: [],
 			stl: "none",
 		}
 	`)
@@ -1444,7 +1422,6 @@ func TestHostSnapshotWithCcHeadersLibrary(t *testing.T) {
 			device_supported: false,
 			host_supported: true,
 			export_include_dirs: ["include"],
-			system_shared_libs: [],
 			stl: "none",
 		}
 	`)
@@ -1498,7 +1475,6 @@ func TestDeviceAndHostSnapshotWithCcHeadersLibrary(t *testing.T) {
 		cc_library_headers {
 			name: "mynativeheaders",
 			host_supported: true,
-			system_shared_libs: [],
 			stl: "none",
 			export_system_include_dirs: ["include"],
 			target: {
@@ -1561,3 +1537,202 @@ include-host/HostTest.h -> include/include-host/HostTest.h
 `),
 	)
 }
+
+func TestSystemSharedLibPropagation(t *testing.T) {
+	result := testSdkWithCc(t, `
+		sdk {
+			name: "mysdk",
+			native_shared_libs: ["sslnil", "sslempty", "sslnonempty"],
+		}
+
+		cc_library {
+			name: "sslnil",
+			host_supported: true,
+		}
+
+		cc_library {
+			name: "sslempty",
+			system_shared_libs: [],
+		}
+
+		cc_library {
+			name: "sslnonempty",
+			system_shared_libs: ["sslnil"],
+		}
+	`)
+
+	result.CheckSnapshot("mysdk", "",
+		checkAndroidBpContents(`
+// This is auto-generated. DO NOT EDIT.
+
+cc_prebuilt_library_shared {
+    name: "mysdk_sslnil@current",
+    sdk_member_name: "sslnil",
+    installable: false,
+    arch: {
+        arm64: {
+            srcs: ["arm64/lib/sslnil.so"],
+        },
+        arm: {
+            srcs: ["arm/lib/sslnil.so"],
+        },
+    },
+}
+
+cc_prebuilt_library_shared {
+    name: "sslnil",
+    prefer: false,
+    arch: {
+        arm64: {
+            srcs: ["arm64/lib/sslnil.so"],
+        },
+        arm: {
+            srcs: ["arm/lib/sslnil.so"],
+        },
+    },
+}
+
+cc_prebuilt_library_shared {
+    name: "mysdk_sslempty@current",
+    sdk_member_name: "sslempty",
+    installable: false,
+    system_shared_libs: [],
+    arch: {
+        arm64: {
+            srcs: ["arm64/lib/sslempty.so"],
+        },
+        arm: {
+            srcs: ["arm/lib/sslempty.so"],
+        },
+    },
+}
+
+cc_prebuilt_library_shared {
+    name: "sslempty",
+    prefer: false,
+    system_shared_libs: [],
+    arch: {
+        arm64: {
+            srcs: ["arm64/lib/sslempty.so"],
+        },
+        arm: {
+            srcs: ["arm/lib/sslempty.so"],
+        },
+    },
+}
+
+cc_prebuilt_library_shared {
+    name: "mysdk_sslnonempty@current",
+    sdk_member_name: "sslnonempty",
+    installable: false,
+    system_shared_libs: ["mysdk_sslnil@current"],
+    arch: {
+        arm64: {
+            srcs: ["arm64/lib/sslnonempty.so"],
+        },
+        arm: {
+            srcs: ["arm/lib/sslnonempty.so"],
+        },
+    },
+}
+
+cc_prebuilt_library_shared {
+    name: "sslnonempty",
+    prefer: false,
+    system_shared_libs: ["sslnil"],
+    arch: {
+        arm64: {
+            srcs: ["arm64/lib/sslnonempty.so"],
+        },
+        arm: {
+            srcs: ["arm/lib/sslnonempty.so"],
+        },
+    },
+}
+
+sdk_snapshot {
+    name: "mysdk@current",
+    native_shared_libs: [
+        "mysdk_sslnil@current",
+        "mysdk_sslempty@current",
+        "mysdk_sslnonempty@current",
+    ],
+}
+`))
+
+	result = testSdkWithCc(t, `
+		sdk {
+			name: "mysdk",
+			host_supported: true,
+			native_shared_libs: ["sslvariants"],
+		}
+
+		cc_library {
+			name: "sslvariants",
+			host_supported: true,
+			target: {
+				android: {
+					system_shared_libs: [],
+				},
+			},
+		}
+	`)
+
+	result.CheckSnapshot("mysdk", "",
+		checkAndroidBpContents(`
+// This is auto-generated. DO NOT EDIT.
+
+cc_prebuilt_library_shared {
+    name: "mysdk_sslvariants@current",
+    sdk_member_name: "sslvariants",
+    host_supported: true,
+    installable: false,
+    target: {
+        android: {
+            system_shared_libs: [],
+        },
+        android_arm64: {
+            srcs: ["android/arm64/lib/sslvariants.so"],
+        },
+        android_arm: {
+            srcs: ["android/arm/lib/sslvariants.so"],
+        },
+        linux_glibc_x86_64: {
+            srcs: ["linux_glibc/x86_64/lib/sslvariants.so"],
+        },
+        linux_glibc_x86: {
+            srcs: ["linux_glibc/x86/lib/sslvariants.so"],
+        },
+    },
+}
+
+cc_prebuilt_library_shared {
+    name: "sslvariants",
+    prefer: false,
+    host_supported: true,
+    target: {
+        android: {
+            system_shared_libs: [],
+        },
+        android_arm64: {
+            srcs: ["android/arm64/lib/sslvariants.so"],
+        },
+        android_arm: {
+            srcs: ["android/arm/lib/sslvariants.so"],
+        },
+        linux_glibc_x86_64: {
+            srcs: ["linux_glibc/x86_64/lib/sslvariants.so"],
+        },
+        linux_glibc_x86: {
+            srcs: ["linux_glibc/x86/lib/sslvariants.so"],
+        },
+    },
+}
+
+sdk_snapshot {
+    name: "mysdk@current",
+    host_supported: true,
+    native_shared_libs: ["mysdk_sslvariants@current"],
+}
+`))
+}