Add support for nocrt by translating it to link_crt in bp2build.

If nocrt is true, then the compilation for cc_shared_library,
cc_binary (shared or static binaries) will _not_ link against their
respective crtbegin and crtend libraries.

nocrt is true only for the Bionic libraries themselves. For everything
else that links against the Bionic runtime, crtbegin and crtend
libraries are used. This makes the "nocrt: false" case the majority.
Hence, if nocrt is explicitly false, we omit the generating attribute in
bp2build.

If nocrt is explicitly true (link_crt is false), the Starlark macro will
disable the link_crt cc_toolchain feature.

Test: new tests
Test: CI
Fixes: 187928070
Fixes: 197946668
Change-Id: I8947789930e599dc802d8eae440859257d044475

5 files changed, 169 insertions, 16 deletions

diff --git a/bp2build/cc_library_conversion_test.go b/bp2build/cc_library_conversion_test.go
index 0d6582294..bfe88f567 100644
--- a/bp2build/cc_library_conversion_test.go
+++ b/bp2build/cc_library_conversion_test.go
@@ -15,6 +15,7 @@
 package bp2build
 
 import (
+	"fmt"
 	"testing"
 
 	"android/soong/android"
@@ -1142,7 +1143,7 @@ cc_library {
 
 func TestCCLibraryNoCrtTrue(t *testing.T) {
 	runCcLibraryTestCase(t, bp2buildTestCase{
-		description:                        "cc_library - simple example",
+		description:                        "cc_library - nocrt: true emits attribute",
 		moduleTypeUnderTest:                "cc_library",
 		moduleTypeUnderTestFactory:         cc.LibraryFactory,
 		moduleTypeUnderTestBp2BuildMutator: cc.CcLibraryBp2Build,
@@ -1150,23 +1151,23 @@ func TestCCLibraryNoCrtTrue(t *testing.T) {
 			"impl.cpp": "",
 		},
 		blueprint: soongCcLibraryPreamble + `
-cc_library_headers { name: "some-headers" }
 cc_library {
     name: "foo-lib",
     srcs: ["impl.cpp"],
-    no_libcrt: true,
+    nocrt: true,
     include_build_directory: false,
 }
 `,
 		expectedBazelTargets: []string{`cc_library(
     name = "foo-lib",
+    link_crt = False,
     srcs = ["impl.cpp"],
-    use_libcrt = False,
 )`}})
 }
 
 func TestCCLibraryNoCrtFalse(t *testing.T) {
 	runCcLibraryTestCase(t, bp2buildTestCase{
+		description:                        "cc_library - nocrt: false - does not emit attribute",
 		moduleTypeUnderTest:                "cc_library",
 		moduleTypeUnderTestFactory:         cc.LibraryFactory,
 		moduleTypeUnderTestBp2BuildMutator: cc.CcLibraryBp2Build,
@@ -1174,23 +1175,22 @@ func TestCCLibraryNoCrtFalse(t *testing.T) {
 			"impl.cpp": "",
 		},
 		blueprint: soongCcLibraryPreamble + `
-cc_library_headers { name: "some-headers" }
 cc_library {
     name: "foo-lib",
     srcs: ["impl.cpp"],
-    no_libcrt: false,
+    nocrt: false,
     include_build_directory: false,
 }
 `,
 		expectedBazelTargets: []string{`cc_library(
     name = "foo-lib",
     srcs = ["impl.cpp"],
-    use_libcrt = True,
 )`}})
 }
 
 func TestCCLibraryNoCrtArchVariant(t *testing.T) {
 	runCcLibraryTestCase(t, bp2buildTestCase{
+		description:                        "cc_library - nocrt in select",
 		moduleTypeUnderTest:                "cc_library",
 		moduleTypeUnderTestFactory:         cc.LibraryFactory,
 		moduleTypeUnderTestBp2BuildMutator: cc.CcLibraryBp2Build,
@@ -1203,27 +1203,45 @@ cc_library {
     srcs: ["impl.cpp"],
     arch: {
         arm: {
-            no_libcrt: true,
+            nocrt: true,
         },
         x86: {
-            no_libcrt: true,
+            nocrt: false,
         },
     },
     include_build_directory: false,
 }
 `,
+		expectedErr: fmt.Errorf("Android.bp:16:1: module \"foo-lib\": nocrt is not supported for arch variants"),
+	})
+}
+
+func TestCCLibraryNoLibCrtTrue(t *testing.T) {
+	runCcLibraryTestCase(t, bp2buildTestCase{
+		description:                        "cc_library - simple example",
+		moduleTypeUnderTest:                "cc_library",
+		moduleTypeUnderTestFactory:         cc.LibraryFactory,
+		moduleTypeUnderTestBp2BuildMutator: cc.CcLibraryBp2Build,
+		filesystem: map[string]string{
+			"impl.cpp": "",
+		},
+		blueprint: soongCcLibraryPreamble + `
+cc_library_headers { name: "some-headers" }
+cc_library {
+    name: "foo-lib",
+    srcs: ["impl.cpp"],
+    no_libcrt: true,
+    include_build_directory: false,
+}
+`,
 		expectedBazelTargets: []string{`cc_library(
     name = "foo-lib",
     srcs = ["impl.cpp"],
-    use_libcrt = select({
-        "//build/bazel/platforms/arch:arm": False,
-        "//build/bazel/platforms/arch:x86": False,
-        "//conditions:default": None,
-    }),
+    use_libcrt = False,
 )`}})
 }
 
-func TestCCLibraryNoCrtArchVariantWithDefault(t *testing.T) {
+func TestCCLibraryNoLibCrtFalse(t *testing.T) {
 	runCcLibraryTestCase(t, bp2buildTestCase{
 		moduleTypeUnderTest:                "cc_library",
 		moduleTypeUnderTestFactory:         cc.LibraryFactory,
@@ -1232,10 +1250,33 @@ func TestCCLibraryNoCrtArchVariantWithDefault(t *testing.T) {
 			"impl.cpp": "",
 		},
 		blueprint: soongCcLibraryPreamble + `
+cc_library_headers { name: "some-headers" }
 cc_library {
     name: "foo-lib",
     srcs: ["impl.cpp"],
     no_libcrt: false,
+    include_build_directory: false,
+}
+`,
+		expectedBazelTargets: []string{`cc_library(
+    name = "foo-lib",
+    srcs = ["impl.cpp"],
+    use_libcrt = True,
+)`}})
+}
+
+func TestCCLibraryNoLibCrtArchVariant(t *testing.T) {
+	runCcLibraryTestCase(t, bp2buildTestCase{
+		moduleTypeUnderTest:                "cc_library",
+		moduleTypeUnderTestFactory:         cc.LibraryFactory,
+		moduleTypeUnderTestBp2BuildMutator: cc.CcLibraryBp2Build,
+		filesystem: map[string]string{
+			"impl.cpp": "",
+		},
+		blueprint: soongCcLibraryPreamble + `
+cc_library {
+    name: "foo-lib",
+    srcs: ["impl.cpp"],
     arch: {
         arm: {
             no_libcrt: true,
@@ -1253,7 +1294,7 @@ cc_library {
     use_libcrt = select({
         "//build/bazel/platforms/arch:arm": False,
         "//build/bazel/platforms/arch:x86": False,
-        "//conditions:default": True,
+        "//conditions:default": None,
     }),
 )`}})
 }
diff --git a/bp2build/cc_library_shared_conversion_test.go b/bp2build/cc_library_shared_conversion_test.go
index 3dcfbd7db..b27206747 100644
--- a/bp2build/cc_library_shared_conversion_test.go
+++ b/bp2build/cc_library_shared_conversion_test.go
@@ -15,6 +15,7 @@
 package bp2build
 
 import (
+	"fmt"
 	"testing"
 
 	"android/soong/android"
@@ -364,3 +365,78 @@ cc_library_shared {
 )`},
 	})
 }
+
+func TestCcLibrarySharedNoCrtTrue(t *testing.T) {
+	runCcLibrarySharedTestCase(t, bp2buildTestCase{
+		description:                        "cc_library_shared - nocrt: true emits attribute",
+		moduleTypeUnderTest:                "cc_library_shared",
+		moduleTypeUnderTestFactory:         cc.LibrarySharedFactory,
+		moduleTypeUnderTestBp2BuildMutator: cc.CcLibrarySharedBp2Build,
+		filesystem: map[string]string{
+			"impl.cpp": "",
+		},
+		blueprint: soongCcLibraryPreamble + `
+cc_library_shared {
+    name: "foo_shared",
+    srcs: ["impl.cpp"],
+    nocrt: true,
+    include_build_directory: false,
+}
+`,
+		expectedBazelTargets: []string{`cc_library_shared(
+    name = "foo_shared",
+    link_crt = False,
+    srcs = ["impl.cpp"],
+)`}})
+}
+
+func TestCcLibrarySharedNoCrtFalse(t *testing.T) {
+	runCcLibrarySharedTestCase(t, bp2buildTestCase{
+		description:                        "cc_library_shared - nocrt: false doesn't emit attribute",
+		moduleTypeUnderTest:                "cc_library_shared",
+		moduleTypeUnderTestFactory:         cc.LibrarySharedFactory,
+		moduleTypeUnderTestBp2BuildMutator: cc.CcLibrarySharedBp2Build,
+		filesystem: map[string]string{
+			"impl.cpp": "",
+		},
+		blueprint: soongCcLibraryPreamble + `
+cc_library_shared {
+    name: "foo_shared",
+    srcs: ["impl.cpp"],
+    nocrt: false,
+    include_build_directory: false,
+}
+`,
+		expectedBazelTargets: []string{`cc_library_shared(
+    name = "foo_shared",
+    srcs = ["impl.cpp"],
+)`}})
+}
+
+func TestCcLibrarySharedNoCrtArchVariant(t *testing.T) {
+	runCcLibrarySharedTestCase(t, bp2buildTestCase{
+		description:                        "cc_library_shared - nocrt in select",
+		moduleTypeUnderTest:                "cc_library_shared",
+		moduleTypeUnderTestFactory:         cc.LibrarySharedFactory,
+		moduleTypeUnderTestBp2BuildMutator: cc.CcLibrarySharedBp2Build,
+		filesystem: map[string]string{
+			"impl.cpp": "",
+		},
+		blueprint: soongCcLibraryPreamble + `
+cc_library_shared {
+    name: "foo_shared",
+    srcs: ["impl.cpp"],
+    arch: {
+        arm: {
+            nocrt: true,
+        },
+        x86: {
+            nocrt: false,
+        },
+    },
+    include_build_directory: false,
+}
+`,
+		expectedErr: fmt.Errorf("Android.bp:16:1: module \"foo_shared\": nocrt is not supported for arch variants"),
+	})
+}
diff --git a/cc/bp2build.go b/cc/bp2build.go
index 22bd90bb0..ebba9d195 100644
--- a/cc/bp2build.go
+++ b/cc/bp2build.go
@@ -364,6 +364,7 @@ type linkerAttributes struct {
 	wholeArchiveDeps          bazel.LabelListAttribute
 	systemDynamicDeps         bazel.LabelListAttribute
 
+	linkCrt                       bazel.BoolAttribute
 	useLibcrt                     bazel.BoolAttribute
 	linkopts                      bazel.StringListAttribute
 	versionScript                 bazel.LabelAttribute
@@ -398,6 +399,7 @@ func bp2BuildParseLinkerProps(ctx android.TopDownMutatorContext, module *Module)
 
 	var linkopts bazel.StringListAttribute
 	var versionScript bazel.LabelAttribute
+	var linkCrt bazel.BoolAttribute
 	var useLibcrt bazel.BoolAttribute
 
 	var stripKeepSymbols bazel.BoolAttribute
@@ -418,6 +420,9 @@ func bp2BuildParseLinkerProps(ctx android.TopDownMutatorContext, module *Module)
 		}
 	}
 
+	// Use a single variable to capture usage of nocrt in arch variants, so there's only 1 error message for this module
+	var disallowedArchVariantCrt bool
+
 	for axis, configToProps := range module.GetArchVariantProperties(ctx, &BaseLinkerProperties{}) {
 		for config, props := range configToProps {
 			if baseLinkerProps, ok := props.(*BaseLinkerProperties); ok {
@@ -457,10 +462,23 @@ func bp2BuildParseLinkerProps(ctx android.TopDownMutatorContext, module *Module)
 					versionScript.SetSelectValue(axis, config, android.BazelLabelForModuleSrcSingle(ctx, *baseLinkerProps.Version_script))
 				}
 				useLibcrt.SetSelectValue(axis, config, baseLinkerProps.libCrt())
+
+				// it's very unlikely for nocrt to be arch variant, so bp2build doesn't support it.
+				if baseLinkerProps.crt() != nil {
+					if axis == bazel.NoConfigAxis {
+						linkCrt.SetSelectValue(axis, config, baseLinkerProps.crt())
+					} else if axis == bazel.ArchConfigurationAxis {
+						disallowedArchVariantCrt = true
+					}
+				}
 			}
 		}
 	}
 
+	if disallowedArchVariantCrt {
+		ctx.ModuleErrorf("nocrt is not supported for arch variants")
+	}
+
 	type productVarDep struct {
 		// the name of the corresponding excludes field, if one exists
 		excludesField string
@@ -530,6 +548,7 @@ func bp2BuildParseLinkerProps(ctx android.TopDownMutatorContext, module *Module)
 		wholeArchiveDeps:          wholeArchiveDeps,
 		systemDynamicDeps:         systemSharedDeps,
 
+		linkCrt:       linkCrt,
 		linkopts:      linkopts,
 		useLibcrt:     useLibcrt,
 		versionScript: versionScript,
diff --git a/cc/library.go b/cc/library.go
index 77eddbf13..58e0e2123 100644
--- a/cc/library.go
+++ b/cc/library.go
@@ -252,6 +252,7 @@ type bazelCcLibraryAttributes struct {
 
 	// This is shared only.
 	Version_script bazel.LabelAttribute
+	Link_crt       bazel.BoolAttribute
 
 	// Common properties shared between both shared and static variants.
 	Shared staticOrSharedAttributes
@@ -321,6 +322,7 @@ func CcLibraryBp2Build(ctx android.TopDownMutatorContext) {
 		Local_includes:              compilerAttrs.localIncludes,
 		Absolute_includes:           compilerAttrs.absoluteIncludes,
 		Linkopts:                    linkerAttrs.linkopts,
+		Link_crt:                    linkerAttrs.linkCrt,
 		Use_libcrt:                  linkerAttrs.useLibcrt,
 		Rtti:                        compilerAttrs.rtti,
 		Stl:                         compilerAttrs.stl,
@@ -2415,6 +2417,7 @@ func ccSharedOrStaticBp2BuildMutatorInternal(ctx android.TopDownMutatorContext,
 			Asflags:    asFlags,
 			Linkopts:   linkerAttrs.linkopts,
 
+			Link_crt:   linkerAttrs.linkCrt,
 			Use_libcrt: linkerAttrs.useLibcrt,
 			Rtti:       compilerAttrs.rtti,
 			Stl:        compilerAttrs.stl,
@@ -2472,6 +2475,7 @@ type bazelCcLibrarySharedAttributes struct {
 	staticOrSharedAttributes
 
 	Linkopts   bazel.StringListAttribute
+	Link_crt   bazel.BoolAttribute // Only for linking shared library (and cc_binary)
 	Use_libcrt bazel.BoolAttribute
 	Rtti       bazel.BoolAttribute
 	Stl        *string
diff --git a/cc/linker.go b/cc/linker.go
index 0d612b583..20e377ceb 100644
--- a/cc/linker.go
+++ b/cc/linker.go
@@ -238,6 +238,19 @@ func invertBoolPtr(value *bool) *bool {
 	return &ret
 }
 
+func (blp *BaseLinkerProperties) crt() *bool {
+	val := invertBoolPtr(blp.Nocrt)
+	if val != nil && *val {
+		// == True
+		//
+		// Since crt is enabled for almost every module compiling against the Bionic runtime,
+		// use `nil` when it's enabled, and rely on the Starlark macro to set it to True by default.
+		// This keeps the BUILD files clean.
+		return nil
+	}
+	return val // can be False or nil
+}
+
 func (blp *BaseLinkerProperties) libCrt() *bool {
 	return invertBoolPtr(blp.No_libcrt)
 }