From ccbe637df0be9d6aa3710a605666f135c071402e Mon Sep 17 00:00:00 2001
From: Sterling Augustine <saugustine@google.com>
Date: Fri, 31 Aug 2018 17:59:03 +0000
Subject: [PATCH] Refactor Addlibgcc to make the when and what logic more
 straightfoward.

Add Android tests.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@341231 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Driver/ToolChains/CommonArgs.cpp | 43 ++++++++++++++++++++--------
 test/Driver/linux-ld.c               | 24 ++++++++++++++++
 2 files changed, 55 insertions(+), 12 deletions(-)

diff --git a/lib/Driver/ToolChains/CommonArgs.cpp b/lib/Driver/ToolChains/CommonArgs.cpp
index 1e093b25b9..9e6aeea958 100644
--- a/lib/Driver/ToolChains/CommonArgs.cpp
+++ b/lib/Driver/ToolChains/CommonArgs.cpp
@@ -1126,23 +1126,42 @@ static void AddLibgcc(const llvm::Triple &Triple, const Driver &D,
   bool IsIAMCU = Triple.isOSIAMCU();
   bool StaticLibgcc = Args.hasArg(options::OPT_static_libgcc) ||
                       Args.hasArg(options::OPT_static);
-  if (!D.CCCIsCXX())
+
+  // The driver ignores -shared-libgcc and therefore treats such cases as
+  // unspecified.  Breaking out the two variables as below makes the current
+  // behavior explicit.
+  bool UnspecifiedLibgcc = !StaticLibgcc;
+  bool SharedLibgcc = !StaticLibgcc;
+
+  // Gcc adds libgcc arguments in various ways:
+  //
+  // gcc <none>: -lgcc --as-needed -lgcc_s --no-as-needed
+  // g++ <none>:                   -lgcc_s               -lgcc
+  // gcc shared:                   -lgcc_s               -lgcc
+  // g++ shared:                   -lgcc_s               -lgcc
+  // gcc static: -lgcc             -lgcc_eh
+  // g++ static: -lgcc             -lgcc_eh
+  //
+  // Also, certain targets need additional adjustments.
+
+  bool LibGccFirst = (D.CCCIsCC() && UnspecifiedLibgcc) || StaticLibgcc;
+  if (LibGccFirst)
     CmdArgs.push_back("-lgcc");
 
-  if (StaticLibgcc || isAndroid) {
-    if (D.CCCIsCXX())
-      CmdArgs.push_back("-lgcc");
-  } else {
-    if (!D.CCCIsCXX() && !isCygMing)
-      CmdArgs.push_back("--as-needed");
+  bool AsNeeded = D.CCCIsCC() && !StaticLibgcc && !isAndroid && !isCygMing;
+  if (AsNeeded)
+    CmdArgs.push_back("--as-needed");
+
+  if ((UnspecifiedLibgcc || SharedLibgcc) && !isAndroid)
     CmdArgs.push_back("-lgcc_s");
-    if (!D.CCCIsCXX() && !isCygMing)
-      CmdArgs.push_back("--no-as-needed");
-  }
 
-  if (StaticLibgcc && !isAndroid && !IsIAMCU)
+  else if (StaticLibgcc && !isAndroid && !IsIAMCU)
     CmdArgs.push_back("-lgcc_eh");
-  else if (!Args.hasArg(options::OPT_shared) && D.CCCIsCXX())
+
+  if (AsNeeded)
+    CmdArgs.push_back("--no-as-needed");
+
+  if (!LibGccFirst)
     CmdArgs.push_back("-lgcc");
 
   // According to Android ABI, we have to link with libdl if we are
diff --git a/test/Driver/linux-ld.c b/test/Driver/linux-ld.c
index 8194b97d3b..6079c7458d 100644
--- a/test/Driver/linux-ld.c
+++ b/test/Driver/linux-ld.c
@@ -230,6 +230,30 @@
 // SKIP-CHECK-CLANG-SHARED-LIBGCC-DYNAMIC: "-lc"
 // SKIP-CHECK-CLANG-SHARED-LIBGCC-DYNAMIC: "-lgcc_s" "-lgcc"
 //
+// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
+// RUN:     --target=aarch64-linux-android -rtlib=platform \
+// RUN:     --gcc-toolchain="" \
+// RUN:     --sysroot=%S/Inputs/basic_linux_tree \
+// RUN:   | FileCheck --check-prefix=CHECK-CLANG-ANDROID-NONE %s
+// CHECK-CLANG-ANDROID-NONE: "{{.*}}ld{{(.exe)?}}" "--sysroot=[[SYSROOT:[^"]+]]"
+// CHECK-CLANG-ANDROID-NONE: "-lgcc" "-ldl" "-lc"
+//
+// RUN: %clang -shared -no-canonical-prefixes %s -### -o %t.o 2>&1 \
+// RUN:     --target=aarch64-linux-android -rtlib=platform \
+// RUN:     --gcc-toolchain="" \
+// RUN:     --sysroot=%S/Inputs/basic_linux_tree \
+// RUN:   | FileCheck --check-prefix=CHECK-CLANG-ANDROID-SHARED %s
+// CHECK-CLANG-ANDROID-SHARED: "{{.*}}ld{{(.exe)?}}" "--sysroot=[[SYSROOT:[^"]+]]"
+// CHECK-CLANG-ANDROID-SHARED: "-lgcc" "-ldl" "-lc"
+//
+// RUN: %clang -static -no-canonical-prefixes %s -### -o %t.o 2>&1 \
+// RUN:     --target=aarch64-linux-android -rtlib=platform \
+// RUN:     --gcc-toolchain="" \
+// RUN:     --sysroot=%S/Inputs/basic_linux_tree \
+// RUN:   | FileCheck --check-prefix=CHECK-CLANG-ANDROID-STATIC %s
+// CHECK-CLANG-ANDROID-STATIC: "{{.*}}ld{{(.exe)?}}" "--sysroot=[[SYSROOT:[^"]+]]"
+// CHECK-CLANG-ANDROID-STATIC: "--start-group" "-lgcc" "-lc" "--end-group"
+//
 // RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1      \
 // RUN:     --target=x86_64-unknown-linux -rtlib=platform \
 // RUN:     -static \
-- 
2.40.0