[clang][InstallAPI] Introduce basic driver to write out tbd files (#81571)

This introduces a basic outline of installapi as a clang driver option.
It captures relevant information as cc1 args, which are common arguments
already passed to the linker to encode into TBD file outputs. This is
effectively an upstream for what already exists as `tapi installapi` in
Xcode toolchains, but directly in Clang. This patch does not handle any
AST traversing on input yet.

InstallAPI is broadly an operation that takes a series of header files
that represent a single dynamic library and generates a TBD file out of
it which represents all the linkable symbols and necessary attributes
for statically linking in clients. It is the linkable object in all
Apple SDKs and when building dylibs in Xcode. `clang -installapi` also
will support verification where it compares all the information recorded
for the TBD files against the already built binary, to catch possible
mismatches like when a declaration is missing a definition for an
exported symbol.

1 files changed, 40 insertions, 1 deletions

diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 8d7b75b..bcb3124 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -149,7 +149,8 @@ CompilerInvocationBase::CompilerInvocationBase()
       FSOpts(std::make_shared<FileSystemOptions>()),
       FrontendOpts(std::make_shared<FrontendOptions>()),
       DependencyOutputOpts(std::make_shared<DependencyOutputOptions>()),
-      PreprocessorOutputOpts(std::make_shared<PreprocessorOutputOptions>()) {}
+      PreprocessorOutputOpts(std::make_shared<PreprocessorOutputOptions>()),
+      InstallAPIOpts(std::make_shared<InstallAPIOptions>()) {}
 
 CompilerInvocationBase &
 CompilerInvocationBase::deep_copy_assign(const CompilerInvocationBase &X) {
@@ -167,6 +168,7 @@ CompilerInvocationBase::deep_copy_assign(const CompilerInvocationBase &X) {
     FrontendOpts = make_shared_copy(X.getFrontendOpts());
     DependencyOutputOpts = make_shared_copy(X.getDependencyOutputOpts());
     PreprocessorOutputOpts = make_shared_copy(X.getPreprocessorOutputOpts());
+    InstallAPIOpts = make_shared_copy(X.getInstallAPIOpts());
   }
   return *this;
 }
@@ -187,6 +189,7 @@ CompilerInvocationBase::shallow_copy_assign(const CompilerInvocationBase &X) {
     FrontendOpts = X.FrontendOpts;
     DependencyOutputOpts = X.DependencyOutputOpts;
     PreprocessorOutputOpts = X.PreprocessorOutputOpts;
+    InstallAPIOpts = X.InstallAPIOpts;
   }
   return *this;
 }
@@ -2158,6 +2161,34 @@ bool CompilerInvocation::ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args,
   return Diags.getNumErrors() == NumErrorsBefore;
 }
 
+static bool ParseInstallAPIArgs(InstallAPIOptions &Opts, ArgList &Args,
+                                DiagnosticsEngine &Diags,
+                                frontend::ActionKind Action) {
+  unsigned NumErrorsBefore = Diags.getNumErrors();
+
+  InstallAPIOptions &InstallAPIOpts = Opts;
+#define INSTALLAPI_OPTION_WITH_MARSHALLING(...)                                \
+  PARSE_OPTION_WITH_MARSHALLING(Args, Diags, __VA_ARGS__)
+#include "clang/Driver/Options.inc"
+#undef INSTALLAPI_OPTION_WITH_MARSHALLING
+  if (Arg *A = Args.getLastArg(options::OPT_current__version))
+    Opts.CurrentVersion.parse64(A->getValue());
+
+  return Diags.getNumErrors() == NumErrorsBefore;
+}
+
+static void GenerateInstallAPIArgs(const InstallAPIOptions &Opts,
+                                   ArgumentConsumer Consumer) {
+  const InstallAPIOptions &InstallAPIOpts = Opts;
+#define INSTALLAPI_OPTION_WITH_MARSHALLING(...)                                \
+  GENERATE_OPTION_WITH_MARSHALLING(Consumer, __VA_ARGS__)
+#include "clang/Driver/Options.inc"
+#undef INSTALLAPI_OPTION_WITH_MARSHALLING
+  if (!Opts.CurrentVersion.empty())
+    GenerateArg(Consumer, OPT_current__version,
+                std::string(Opts.CurrentVersion));
+}
+
 static void GenerateDependencyOutputArgs(const DependencyOutputOptions &Opts,
                                          ArgumentConsumer Consumer) {
   const DependencyOutputOptions &DependencyOutputOpts = Opts;
@@ -2557,6 +2588,7 @@ static const auto &getFrontendActionTable() {
       {frontend::GeneratePCH, OPT_emit_pch},
       {frontend::GenerateInterfaceStubs, OPT_emit_interface_stubs},
       {frontend::InitOnly, OPT_init_only},
+      {frontend::InstallAPI, OPT_installapi},
       {frontend::ParseSyntaxOnly, OPT_fsyntax_only},
       {frontend::ModuleFileInfo, OPT_module_file_info},
       {frontend::VerifyPCH, OPT_verify_pch},
@@ -4280,6 +4312,7 @@ static bool isStrictlyPreprocessorAction(frontend::ActionKind Action) {
   case frontend::GenerateHeaderUnit:
   case frontend::GeneratePCH:
   case frontend::GenerateInterfaceStubs:
+  case frontend::InstallAPI:
   case frontend::ParseSyntaxOnly:
   case frontend::ModuleFileInfo:
   case frontend::VerifyPCH:
@@ -4654,6 +4687,11 @@ bool CompilerInvocation::CreateFromArgsImpl(
       Res.getDependencyOutputOpts().Targets.empty())
     Diags.Report(diag::err_fe_dependency_file_requires_MT);
 
+  if (Args.hasArg(OPT_installapi)) {
+    ParseInstallAPIArgs(Res.getInstallAPIOpts(), Args, Diags,
+                        Res.getFrontendOpts().ProgramAction);
+  }
+
   // If sanitizer is enabled, disable OPT_ffine_grained_bitfield_accesses.
   if (Res.getCodeGenOpts().FineGrainedBitfieldAccesses &&
       !Res.getLangOpts().Sanitize.empty()) {
@@ -4844,6 +4882,7 @@ void CompilerInvocationBase::generateCC1CommandLine(
   GeneratePreprocessorOutputArgs(getPreprocessorOutputOpts(), Consumer,
                                  getFrontendOpts().ProgramAction);
   GenerateDependencyOutputArgs(getDependencyOutputOpts(), Consumer);
+  GenerateInstallAPIArgs(getInstallAPIOpts(), Consumer);
 }
 
 std::vector<std::string> CompilerInvocationBase::getCC1CommandLine() const {