From fa2412b2e706d18c1afb7f70f34353baebb9c0ba Mon Sep 17 00:00:00 2001
From: Stephen Hines <srhines@google.com>
Date: Tue, 25 Oct 2016 21:44:35 +0000
Subject: [PATCH] Use linker flag --fix-cortex-a53-843419 on Android ARM64
 compilation.

Summary:
This is only forced on if there is no non-Cortex-A53 CPU specified as
well. Android's platform and NDK builds need to assume that the code can
be run on Cortex-A53 devices, so we always enable the fix unless we know
specifically that the code is only running on a different kind of CPU.

Reviewers: cfe-commits

Subscribers: aemerson, rengolin, tberghammer, pirama, danalbert

Differential Revision: https://reviews.llvm.org/D25761

llvm-svn: 285127
---
 clang/lib/Driver/Tools.cpp                 |  8 ++++++++
 clang/test/Driver/android-aarch64-link.cpp | 17 +++++++++++++++++
 2 files changed, 25 insertions(+)
 create mode 100644 clang/test/Driver/android-aarch64-link.cpp

diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index 7d77cd1..691bb85 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -9712,6 +9712,14 @@ void gnutools::Linker::ConstructJob(Compilation &C, const JobAction &JA,
   if (Arch == llvm::Triple::armeb || Arch == llvm::Triple::thumbeb)
     arm::appendEBLinkFlags(Args, CmdArgs, Triple);
 
+  // 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");
+  }
+
   for (const auto &Opt : ToolChain.ExtraOpts)
     CmdArgs.push_back(Opt.c_str());
 
diff --git a/clang/test/Driver/android-aarch64-link.cpp b/clang/test/Driver/android-aarch64-link.cpp
new file mode 100644
index 0000000..2c4cfb9
--- /dev/null
+++ b/clang/test/Driver/android-aarch64-link.cpp
@@ -0,0 +1,17 @@
+// Check that we automatically add relevant linker flags for Android aarch64.
+
+// RUN: %clang -target aarch64-none-linux-android \
+// RUN:   -### -v %s 2> %t
+// RUN: FileCheck -check-prefix=GENERIC-ARM < %t %s
+//
+// RUN: %clang -target aarch64-none-linux-android \
+// RUN:   -mcpu=cortex-a53 -### -v %s 2> %t
+// RUN: FileCheck -check-prefix=CORTEX-A53 < %t %s
+//
+// RUN: %clang -target aarch64-none-linux-android \
+// RUN:   -mcpu=cortex-a57 -### -v %s 2> %t
+// RUN: FileCheck -check-prefix=CORTEX-A57 < %t %s
+//
+// GENERIC-ARM: --fix-cortex-a53-843419
+// CORTEX-A53: --fix-cortex-a53-843419
+// CORTEX-A57-NOT: --fix-cortex-a53-843419
-- 
2.7.4