[Driver] Use --android-tls for Android ARM/AArch64 when lld is used

[MaskRay]

Summary

See D61825 for the temporary lld option --android-tls.

[rprichard]

lib/Driver/ToolChains/Gnu.cpp

404

The logic used for Fuschia is more precise:

const char *Exec = Args.MakeArgString(ToolChain.GetLinkerPath());
if (llvm::sys::path::filename(Exec).equals_lower("ld.lld") ||
    llvm::sys::path::stem(Exec).equals_lower("ld.lld")) {
  CmdArgs.push_back("-z");
  CmdArgs.push_back("rodynamic");
}

[MaskRay]

Use Args.MakeArgString(ToolChain.GetLinkerPath());

[srhines]

This LGTM if Ryan is happy with it. Thanks for taking care of getting a workaround implemented until this can be fixed.

[MaskRay]

Abandon in favor of D62055

lib/Driver/ToolChains/Gnu.cpp

void tools::gnutools::Linker::ConstructJob(Compilation &C, const JobAction &JA,
   // Most Android ARM64 targets should enable the linker fix for erratum
   // 843419. Only non-Cortex-A53 devices are allowed to skip this flag.
   if (Arch == llvm::Triple::aarch64 && isAndroid) {
     std::string CPU = getCPUName(Args, Triple);
     if (CPU.empty() || CPU == "generic" || CPU == "cortex-a53")
       CmdArgs.push_back("--fix-cortex-a53-843419");
   }
 
+  if (isAndroid) {
     // Android does not allow shared text relocations. Emit a warning if the
     // user's code contains any.
-  if (isAndroid)
-      CmdArgs.push_back("--warn-shared-textrel");
 
+    // FIXME In lld, --android-tls is a temporary option that makes its TLS
+    // layout compatible with Android Bionic on ARM/AArch64. Delete once the
+    // reservation of extra TLS slots is done in a proper layer (e.g.
+    // crtbegin_{dynamic,static}.o).
+    if (Triple.isARM() || Triple.isAArch64()) {
+      const char *Exec = Args.MakeArgString(ToolChain.GetLinkerPath());
+      if (llvm::sys::path::filename(Exec).equals_lower("ld.lld") ||
+          llvm::sys::path::stem(Exec).equals_lower("ld.lld"))
+        CmdArgs.push_back("--android-tls");
+    }
+  }
+
   for (const auto &Opt : ToolChain.ExtraOpts)
     CmdArgs.push_back(Opt.c_str());
 
   CmdArgs.push_back("--eh-frame-hdr");
 
   if (const char *LDMOption = getLDMOption(ToolChain.getTriple(), Args)) {
     CmdArgs.push_back("-m");
     CmdArgs.push_back(LDMOption);

test/Driver/android-aarch64-link.cpp

 // RUN: %clang -target aarch64-none-linux-android \
 // RUN:   -mcpu=cortex-a57 -### -v %s 2> %t
 // RUN: FileCheck -check-prefix=CORTEX-A57 < %t %s
 //
 // RUN: %clang -target aarch64-none-linux-android \
 // RUN:   -### -v %s 2> %t
 // RUN: FileCheck -check-prefix=MAX-PAGE-SIZE < %t %s
 //
+// RUN: %clang -target aarch64-linux-android -### %s 2>&1 | \
+// RUN:   FileCheck --implicit-check-not=--android-tls /dev/null
+// RUN: %clang -target aarch64-linux-android -fuse-ld=lld -### %s 2>&1 | \
+// RUN:   FileCheck --check-prefix=TLS %s
+//
 // GENERIC-ARM: --fix-cortex-a53-843419
 // CORTEX-A53: --fix-cortex-a53-843419
 // CORTEX-A57-NOT: --fix-cortex-a53-843419
 // MAX-PAGE-SIZE: max-page-size=4096
+// TLS: --android-tls

test/Driver/android-arm-link.cpp

+// RUN: %clang -target arm-linux-androideabi -### %s 2>&1 | \
+// RUN:   FileCheck --implicit-check-not=--android-tls /dev/null
+// RUN: %clang -target arm-linux-androideabi -fuse-ld=lld -### %s 2>&1 | \
+// RUN:   FileCheck --check-prefix=TLS %s
+
+// TLS: --android-tls