[memprof] Export __memprof_default_options_str on Darwin

Author: ellishg

clang/lib/Driver/ToolChains/Darwin.cpp

@@ -1617,6 +1617,10 @@ void DarwinClang::AddLinkRuntimeLibArgs(const ArgList &Args,
     }
   }
 
+  if (Sanitize.needsMemProfRt())
+    if (hasExportSymbolDirective(Args))
+      addExportedSymbol(CmdArgs, "___memprof_default_options_str");
+
   const XRayArgs &XRay = getXRayArgs();
   if (XRay.needsXRayRt()) {
     AddLinkRuntimeLib(Args, CmdArgs, "xray");

clang/test/Driver/fmemprof.cpp

@@ -17,3 +17,11 @@
 
 // RUN: not %clangxx --target=x86_64-linux-gnu -fprofile-generate -fmemory-profile-use=foo %s -### 2>&1 | FileCheck %s --check-prefix=CONFLICTWITHPGOINSTR
 // CONFLICTWITHPGOINSTR: error: invalid argument '-fmemory-profile-use=foo' not allowed with '-fprofile-generate'
+
+// Test that we export the __memprof_default_options_str on Darwin because it has WeakAnyLinkage
+// RUN: %clangxx --target=arm64-apple-ios -fmemory-profile %s -### 2>&1 | FileCheck %s -check-prefix=EXPORT-BASE --implicit-check-not=exported_symbol
+// RUN: %clangxx --target=x86_64-linux-gnu -fmemory-profile %s -### 2>&1 | FileCheck %s -check-prefix=EXPORT-BASE --implicit-check-not=exported_symbol
+// RUN: %clangxx --target=arm64-apple-ios -fmemory-profile -exported_symbols_list /dev/null %s -### 2>&1 | FileCheck %s --check-prefixes=EXPORT-BASE,EXPORT
+// FIXME: Darwin needs to link in the runtime, then we can use the regular CHECK prefix
+// EXPORT-BASE: "-cc1" {{.*}} "-fmemory-profile"
+// EXPORT: "-exported_symbol" "___memprof_default_options_str"