[gcov/Darwin] Ensure external symbols are exported when using an export list

Make sure that symbols needed to implement runtime support for gcov are
exported when using an export list on Darwin.

Without the clang driver exporting these symbols, the linker hides them,
resulting in tapi verification failures.

rdar://45944768

Differential Revision: https://reviews.llvm.org/D55151

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@348187 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/Driver/ToolChain.h

@@ -381,6 +381,9 @@ public:
   /// needsProfileRT - returns true if instrumentation profile is on.
   static bool needsProfileRT(const llvm::opt::ArgList &Args);
 
+  /// Returns true if gcov instrumentation (-fprofile-arcs or --coverage) is on.
+  static bool needsGCovInstrumentation(const llvm::opt::ArgList &Args);
+
   /// IsUnwindTablesDefault - Does this tool chain use -funwind-tables
   /// by default.
   virtual bool IsUnwindTablesDefault(const llvm::opt::ArgList &Args) const;

lib/Driver/ToolChain.cpp

@@ -403,19 +403,23 @@ std::string ToolChain::getArchSpecificLibPath() const {
 }
 
 bool ToolChain::needsProfileRT(const ArgList &Args) {
-  if (Args.hasFlag(options::OPT_fprofile_arcs, options::OPT_fno_profile_arcs,
-                   false) ||
+  if (needsGCovInstrumentation(Args) ||
       Args.hasArg(options::OPT_fprofile_generate) ||
       Args.hasArg(options::OPT_fprofile_generate_EQ) ||
       Args.hasArg(options::OPT_fprofile_instr_generate) ||
       Args.hasArg(options::OPT_fprofile_instr_generate_EQ) ||
-      Args.hasArg(options::OPT_fcreate_profile) ||
-      Args.hasArg(options::OPT_coverage))
+      Args.hasArg(options::OPT_fcreate_profile))
     return true;
 
   return false;
 }
 
+bool ToolChain::needsGCovInstrumentation(const llvm::opt::ArgList &Args) {
+  return Args.hasFlag(options::OPT_fprofile_arcs, options::OPT_fno_profile_arcs,
+                      false) ||
+         Args.hasArg(options::OPT_coverage);
+}
+
 Tool *ToolChain::SelectTool(const JobAction &JA) const {
   if (getDriver().ShouldUseClangCompiler(JA)) return getClang();
   Action::ActionClass AC = JA.getKind();

lib/Driver/ToolChains/Darwin.cpp

@@ -1034,11 +1034,17 @@ void Darwin::addProfileRTLibs(const ArgList &Args,
   // runtime, automatically export symbols necessary to implement some of the
   // runtime's functionality.
   if (hasExportSymbolDirective(Args)) {
-    addExportedSymbol(CmdArgs, "___llvm_profile_filename");
-    addExportedSymbol(CmdArgs, "___llvm_profile_raw_version");
-    addExportedSymbol(CmdArgs, "_lprofCurFilename");
+    if (needsGCovInstrumentation(Args)) {
+      addExportedSymbol(CmdArgs, "___gcov_flush");
+      addExportedSymbol(CmdArgs, "_flush_fn_list");
+      addExportedSymbol(CmdArgs, "_writeout_fn_list");
+    } else {
+      addExportedSymbol(CmdArgs, "___llvm_profile_filename");
+      addExportedSymbol(CmdArgs, "___llvm_profile_raw_version");
+      addExportedSymbol(CmdArgs, "_lprofCurFilename");
+      addExportedSymbol(CmdArgs, "_lprofMergeValueProfData");
+    }
     addExportedSymbol(CmdArgs, "_lprofDirMode");
-    addExportedSymbol(CmdArgs, "_lprofMergeValueProfData");
   }
 }
 

test/Driver/darwin-ld.c

@@ -341,10 +341,22 @@
 // RUN: FileCheck -check-prefix=PROFILE_EXPORT %s < %t.log
 // PROFILE_EXPORT: "-exported_symbol" "___llvm_profile_filename" "-exported_symbol" "___llvm_profile_raw_version" "-exported_symbol" "_lprofCurFilename"
 //
-// RUN: %clang -target x86_64-apple-darwin12 -fprofile-instr-generate -### %t.o 2> %t.log
+// RUN: %clang -target x86_64-apple-darwin12 -fprofile-instr-generate --coverage -### %t.o 2> %t.log
 // RUN: FileCheck -check-prefix=NO_PROFILE_EXPORT %s < %t.log
 // NO_PROFILE_EXPORT-NOT: "-exported_symbol"
 //
+// RUN: %clang -target x86_64-apple-darwin12 --coverage -exported_symbols_list /dev/null -### %t.o 2> %t.log
+// RUN: FileCheck -check-prefix=GCOV_EXPORT %s < %t.log
+// RUN: %clang -target x86_64-apple-darwin12 -fprofile-arcs -Wl,-exported_symbols_list,/dev/null -### %t.o 2> %t.log
+// RUN: FileCheck -check-prefix=GCOV_EXPORT %s < %t.log
+// RUN: %clang -target x86_64-apple-darwin12 -fprofile-arcs -Wl,-exported_symbol,foo -### %t.o 2> %t.log
+// RUN: FileCheck -check-prefix=GCOV_EXPORT %s < %t.log
+// RUN: %clang -target x86_64-apple-darwin12 -fprofile-arcs -Xlinker -exported_symbol -Xlinker foo -### %t.o 2> %t.log
+// RUN: FileCheck -check-prefix=GCOV_EXPORT %s < %t.log
+// RUN: %clang -target x86_64-apple-darwin12 -fprofile-arcs -Xlinker -exported_symbols_list -Xlinker /dev/null -### %t.o 2> %t.log
+// RUN: FileCheck -check-prefix=GCOV_EXPORT %s < %t.log
+// GCOV_EXPORT: "-exported_symbol" "___gcov_flush"
+//
 // Check that we can pass the outliner down to the linker.
 // RUN: env IPHONEOS_DEPLOYMENT_TARGET=7.0 \
 // RUN:   %clang -target arm64-apple-darwin -moutline -### %t.o 2> %t.log