private TransitiveLipoInfoProvider collectTransitiveLipoInfo(CcCompilationOutputs outputs) {
if (CppHelper.getFdoSupport(ruleContext).getFdoRoot() == null) {
return TransitiveLipoInfoProvider.EMPTY;
}
NestedSetBuilder<IncludeScannable> scannableBuilder = NestedSetBuilder.stableOrder();
// TODO(bazel-team): Only fetch the STL prerequisite in one place.
TransitiveInfoCollection stl = ruleContext.getPrerequisite(":stl", Mode.TARGET);
if (stl != null) {
TransitiveLipoInfoProvider provider = stl.getProvider(TransitiveLipoInfoProvider.class);
if (provider != null) {
scannableBuilder.addTransitive(provider.getTransitiveIncludeScannables());
}
}
for (TransitiveLipoInfoProvider dep :
AnalysisUtils.getProviders(deps, TransitiveLipoInfoProvider.class)) {
scannableBuilder.addTransitive(dep.getTransitiveIncludeScannables());
}
for (IncludeScannable scannable : outputs.getLipoScannables()) {
Preconditions.checkState(scannable.getIncludeScannerSources().size() == 1);
scannableBuilder.add(scannable);
}
return new TransitiveLipoInfoProvider(scannableBuilder.build());
}
/**
* Constructs the C++ linker actions. It generally generates two actions, one for a static library
* and one for a dynamic library. If PIC is required for shared libraries, but not for binaries,
* it additionally creates a third action to generate a PIC static library.
*
* <p>For dynamic libraries, this method can additionally create an interface shared library that
* can be used for linking, but doesn't contain any executable code. This increases the number of
* cache hits for link actions. Call {@link #setAllowInterfaceSharedObjects(boolean)} to enable
* this behavior.
*
* @throws RuleErrorException
*/
public CcLinkingOutputs createCcLinkActions(CcCompilationOutputs ccOutputs)
throws RuleErrorException {
// For now only handle static links. Note that the dynamic library link below ignores linkType.
// TODO(bazel-team): Either support non-static links or move this check to setLinkType().
Preconditions.checkState(linkType.isStaticLibraryLink(), "can only handle static links");
CcLinkingOutputs.Builder result = new CcLinkingOutputs.Builder();
if (cppConfiguration.isLipoContextCollector()) {
// Don't try to create LIPO link actions in collector mode,
// because it needs some data that's not available at this point.
return result.build();
}
AnalysisEnvironment env = ruleContext.getAnalysisEnvironment();
boolean usePicForBinaries = CppHelper.usePic(ruleContext, true);
boolean usePicForSharedLibs = CppHelper.usePic(ruleContext, false);
// Create static library (.a). The linkType only reflects whether the library is alwayslink or
// not. The PIC-ness is determined by whether we need to use PIC or not. There are three cases
// for (usePicForSharedLibs usePicForBinaries):
//
// (1) (false false) -> no pic code
// (2) (true false) -> shared libraries as pic, but not binaries
// (3) (true true) -> both shared libraries and binaries as pic
//
// In case (3), we always need PIC, so only create one static library containing the PIC object
// files. The name therefore does not match the content.
//
// Presumably, it is done this way because the .a file is an implicit output of every cc_library
// rule, so we can't use ".pic.a" that in the always-PIC case.
// If the crosstool is configured to select an output artifact, we use that selection.
// Otherwise, we use linux defaults.
Artifact linkedArtifact = getLinkedArtifact(linkType);
CppLinkAction maybePicAction =
newLinkActionBuilder(linkedArtifact)
.addNonLibraryInputs(ccOutputs.getObjectFiles(usePicForBinaries))
.addNonLibraryInputs(ccOutputs.getHeaderTokenFiles())
.addLTOBitcodeFiles(ccOutputs.getLtoBitcodeFiles())
.setLinkType(linkType)
.setLinkStaticness(LinkStaticness.FULLY_STATIC)
.setFeatureConfiguration(featureConfiguration)
.build();
env.registerAction(maybePicAction);
result.addStaticLibrary(maybePicAction.getOutputLibrary());
// Create a second static library (.pic.a). Only in case (2) do we need both PIC and non-PIC
// static libraries. In that case, the first static library contains the non-PIC code, and this
// one contains the PIC code, so the names match the content.
if (!usePicForBinaries && usePicForSharedLibs) {
LinkTargetType picLinkType =
(linkType == LinkTargetType.ALWAYS_LINK_STATIC_LIBRARY)
? LinkTargetType.ALWAYS_LINK_PIC_STATIC_LIBRARY
: LinkTargetType.PIC_STATIC_LIBRARY;
// If the crosstool is configured to select an output artifact, we use that selection.
// Otherwise, we use linux defaults.
Artifact picArtifact = getLinkedArtifact(picLinkType);
CppLinkAction picAction =
newLinkActionBuilder(picArtifact)
.addNonLibraryInputs(ccOutputs.getObjectFiles(true))
.addNonLibraryInputs(ccOutputs.getHeaderTokenFiles())
.addLTOBitcodeFiles(ccOutputs.getLtoBitcodeFiles())
.setLinkType(picLinkType)
.setLinkStaticness(LinkStaticness.FULLY_STATIC)
.setFeatureConfiguration(featureConfiguration)
.build();
env.registerAction(picAction);
result.addPicStaticLibrary(picAction.getOutputLibrary());
}
if (!createDynamicLibrary) {
return result.build();
}
// Create dynamic library.
Artifact soImpl;
if (soImplArtifact == null) {
// If the crosstool is configured to select an output artifact, we use that selection.
// Otherwise, we use linux defaults.
soImpl = getLinkedArtifact(LinkTargetType.DYNAMIC_LIBRARY);
} else {
soImpl = soImplArtifact;
}
List<String> sonameLinkopts = ImmutableList.of();
Artifact soInterface = null;
if (cppConfiguration.useInterfaceSharedObjects() && allowInterfaceSharedObjects) {
soInterface =
CppHelper.getLinuxLinkedArtifact(ruleContext, LinkTargetType.INTERFACE_DYNAMIC_LIBRARY);
sonameLinkopts =
ImmutableList.of(
"-Wl,-soname="
+ SolibSymlinkAction.getDynamicLibrarySoname(
soImpl.getRootRelativePath(), false));
}
// Should we also link in any libraries that this library depends on?
// That is required on some systems...
CppLinkActionBuilder linkActionBuilder =
newLinkActionBuilder(soImpl)
.setInterfaceOutput(soInterface)
.addNonLibraryInputs(ccOutputs.getObjectFiles(usePicForSharedLibs))
.addNonLibraryInputs(ccOutputs.getHeaderTokenFiles())
.addLTOBitcodeFiles(ccOutputs.getLtoBitcodeFiles())
.setLinkType(LinkTargetType.DYNAMIC_LIBRARY)
.setLinkStaticness(LinkStaticness.DYNAMIC)
.addLinkopts(linkopts)
.addLinkopts(sonameLinkopts)
.setRuntimeInputs(
CppHelper.getToolchain(ruleContext).getDynamicRuntimeLinkMiddleman(),
CppHelper.getToolchain(ruleContext).getDynamicRuntimeLinkInputs())
.setFeatureConfiguration(featureConfiguration);
if (!ccOutputs.getLtoBitcodeFiles().isEmpty()
&& featureConfiguration.isEnabled(CppRuleClasses.THIN_LTO)) {
linkActionBuilder.setLTOIndexing(true);
CppLinkAction indexAction = linkActionBuilder.build();
env.registerAction(indexAction);
for (LTOBackendArtifacts ltoArtifacts : indexAction.getAllLTOBackendArtifacts()) {
ltoArtifacts.scheduleLTOBackendAction(ruleContext, usePicForSharedLibs);
}
linkActionBuilder.setLTOIndexing(false);
}
CppLinkAction action = linkActionBuilder.build();
env.registerAction(action);
LibraryToLink dynamicLibrary = action.getOutputLibrary();
LibraryToLink interfaceLibrary = action.getInterfaceOutputLibrary();
if (interfaceLibrary == null) {
interfaceLibrary = dynamicLibrary;
}
// If shared library has neverlink=1, then leave it untouched. Otherwise,
// create a mangled symlink for it and from now on reference it through
// mangled name only.
if (neverLink) {
result.addDynamicLibrary(interfaceLibrary);
result.addExecutionDynamicLibrary(dynamicLibrary);
} else {
LibraryToLink libraryLink =
SolibSymlinkAction.getDynamicLibrarySymlink(
ruleContext,
interfaceLibrary.getArtifact(),
false,
false,
ruleContext.getConfiguration());
result.addDynamicLibrary(libraryLink);
LibraryToLink implLibraryLink =
SolibSymlinkAction.getDynamicLibrarySymlink(
ruleContext,
dynamicLibrary.getArtifact(),
false,
false,
ruleContext.getConfiguration());
result.addExecutionDynamicLibrary(implLibraryLink);
}
return result.build();
}
private NestedSet<Artifact> getTemps(CcCompilationOutputs compilationOutputs) {
return ruleContext.getFragment(CppConfiguration.class).isLipoContextCollector()
? NestedSetBuilder.<Artifact>emptySet(Order.STABLE_ORDER)
: compilationOutputs.getTemps();
}
/** Create the C++ compile and link actions, and the corresponding C++-related providers. */
public Info build() {
// Fail early if there is no lipo context collector on the rule - otherwise we end up failing
// in lipo optimization.
Preconditions.checkState(
// 'cc_inc_library' rules do not compile, and thus are not affected by LIPO.
ruleContext.getRule().getRuleClass().equals("cc_inc_library")
|| ruleContext.getRule().isAttrDefined(":lipo_context_collector", BuildType.LABEL));
if (checkDepsGenerateCpp) {
for (LanguageDependentFragment dep :
AnalysisUtils.getProviders(deps, LanguageDependentFragment.class)) {
LanguageDependentFragment.Checker.depSupportsLanguage(
ruleContext, dep, CppRuleClasses.LANGUAGE);
}
}
CppModel model = initializeCppModel();
CppCompilationContext cppCompilationContext = initializeCppCompilationContext(model);
model.setContext(cppCompilationContext);
boolean compileHeaderModules = featureConfiguration.isEnabled(CppRuleClasses.HEADER_MODULES);
Preconditions.checkState(
!compileHeaderModules || cppCompilationContext.getCppModuleMap() != null,
"All cc rules must support module maps.");
// Create compile actions (both PIC and non-PIC).
CcCompilationOutputs ccOutputs = model.createCcCompileActions();
if (!objectFiles.isEmpty() || !picObjectFiles.isEmpty()) {
// Merge the pre-compiled object files into the compiler outputs.
ccOutputs =
new CcCompilationOutputs.Builder()
.merge(ccOutputs)
.addLTOBitcodeFile(ccOutputs.getLtoBitcodeFiles())
.addObjectFiles(objectFiles)
.addPicObjectFiles(picObjectFiles)
.build();
}
// Create link actions (only if there are object files or if explicitly requested).
CcLinkingOutputs ccLinkingOutputs = CcLinkingOutputs.EMPTY;
if (emitLinkActionsIfEmpty || !ccOutputs.isEmpty()) {
// On some systems, the linker gives an error message if there are no input files. Even with
// the check above, this can still happen if there is a .nopic.o or .o files in srcs, but no
// other files. To fix that, we'd have to check for each link action individually.
//
// An additional pre-existing issue is that the header check tokens are dropped if we don't
// generate any link actions, effectively disabling header checking in some cases.
if (linkType.isStaticLibraryLink()) {
// TODO(bazel-team): This can't create the link action for a cc_binary yet.
ccLinkingOutputs = model.createCcLinkActions(ccOutputs);
}
}
CcLinkingOutputs originalLinkingOutputs = ccLinkingOutputs;
if (!(staticLibraries.isEmpty()
&& picStaticLibraries.isEmpty()
&& dynamicLibraries.isEmpty())) {
// Merge the pre-compiled libraries (static & dynamic) into the linker outputs.
ccLinkingOutputs =
new CcLinkingOutputs.Builder()
.merge(ccLinkingOutputs)
.addStaticLibraries(staticLibraries)
.addPicStaticLibraries(picStaticLibraries)
.addDynamicLibraries(dynamicLibraries)
.addExecutionDynamicLibraries(dynamicLibraries)
.build();
}
DwoArtifactsCollector dwoArtifacts = DwoArtifactsCollector.transitiveCollector(ccOutputs, deps);
Runfiles cppStaticRunfiles = collectCppRunfiles(ccLinkingOutputs, true);
Runfiles cppSharedRunfiles = collectCppRunfiles(ccLinkingOutputs, false);
// By very careful when adding new providers here - it can potentially affect a lot of rules.
// We should consider merging most of these providers into a single provider.
Map<Class<? extends TransitiveInfoProvider>, TransitiveInfoProvider> providers =
new LinkedHashMap<>();
providers.put(
CppRunfilesProvider.class, new CppRunfilesProvider(cppStaticRunfiles, cppSharedRunfiles));
providers.put(CppCompilationContext.class, cppCompilationContext);
providers.put(
CppDebugFileProvider.class,
new CppDebugFileProvider(
dwoArtifacts.getDwoArtifacts(), dwoArtifacts.getPicDwoArtifacts()));
providers.put(TransitiveLipoInfoProvider.class, collectTransitiveLipoInfo(ccOutputs));
Map<String, NestedSet<Artifact>> outputGroups = new TreeMap<>();
outputGroups.put(OutputGroupProvider.TEMP_FILES, getTemps(ccOutputs));
if (emitCompileProviders) {
boolean isLipoCollector =
ruleContext.getFragment(CppConfiguration.class).isLipoContextCollector();
boolean processHeadersInDependencies =
ruleContext.getFragment(CppConfiguration.class).processHeadersInDependencies();
boolean usePic = CppHelper.usePic(ruleContext, false);
outputGroups.put(
OutputGroupProvider.FILES_TO_COMPILE,
ccOutputs.getFilesToCompile(isLipoCollector, processHeadersInDependencies, usePic));
outputGroups.put(
OutputGroupProvider.COMPILATION_PREREQUISITES,
CcCommon.collectCompilationPrerequisites(ruleContext, cppCompilationContext));
}
// TODO(bazel-team): Maybe we can infer these from other data at the places where they are
// used.
if (emitCcNativeLibrariesProvider) {
providers.put(
CcNativeLibraryProvider.class,
new CcNativeLibraryProvider(collectNativeCcLibraries(ccLinkingOutputs)));
}
providers.put(
CcExecutionDynamicLibrariesProvider.class,
collectExecutionDynamicLibraryArtifacts(ccLinkingOutputs.getExecutionDynamicLibraries()));
boolean forcePic = ruleContext.getFragment(CppConfiguration.class).forcePic();
if (emitCcSpecificLinkParamsProvider) {
providers.put(
CcSpecificLinkParamsProvider.class,
new CcSpecificLinkParamsProvider(
createCcLinkParamsStore(ccLinkingOutputs, cppCompilationContext, forcePic)));
} else {
providers.put(
CcLinkParamsProvider.class,
new CcLinkParamsProvider(
createCcLinkParamsStore(ccLinkingOutputs, cppCompilationContext, forcePic)));
}
return new Info(
providers,
outputGroups,
ccOutputs,
ccLinkingOutputs,
originalLinkingOutputs,
cppCompilationContext);
}
