[ARM] Pass subtarget feature "+long-calls" instead of passing backend…

… option

"-arm-long-calls".

This change allows using -mlong-calls/-mno-long-calls for LTO and enabling or
disabling long call on a per-function basis.

rdar://problem/21529937

Differential Revision: http://reviews.llvm.org/D9414

llvm-svn: 241565

clang/lib/Driver/Tools.cpp

@@ -638,6 +638,8 @@ static void getARMTargetFeatures(const Driver &D, const llvm::Triple &Triple,
                                  const ArgList &Args,
                                  std::vector<const char *> &Features,
                                  bool ForAS) {
+  bool KernelOrKext =
+      Args.hasArg(options::OPT_mkernel, options::OPT_fapple_kext);
   StringRef FloatABI = tools::arm::getARMFloatABI(D, Args, Triple);
   if (!ForAS) {
     // FIXME: Note, this is a hack, the LLVM backend doesn't actually use these
@@ -705,6 +707,14 @@ static void getARMTargetFeatures(const Driver &D, const llvm::Triple &Triple,
   if (Triple.getSubArch() == llvm::Triple::SubArchType::ARMSubArch_v8_1a) {
     Features.insert(Features.begin(), "+v8.1a");
   }
+
+  if (Arg *A = Args.getLastArg(options::OPT_mlong_calls,
+                               options::OPT_mno_long_calls)) {
+    if (A->getOption().matches(options::OPT_mlong_calls))
+      Features.push_back("+long-calls");
+  } else if (KernelOrKext && (!Triple.isiOS() || Triple.isOSVersionLT(6))) {
+      Features.push_back("+long-calls");
+  }
 }
 
 void Clang::AddARMTargetArgs(const ArgList &Args, ArgStringList &CmdArgs,
@@ -778,11 +788,6 @@ void Clang::AddARMTargetArgs(const ArgList &Args, ArgStringList &CmdArgs,
 
   // Kernel code has more strict alignment requirements.
   if (KernelOrKext) {
-    if (!Triple.isiOS() || Triple.isOSVersionLT(6)) {
-      CmdArgs.push_back("-backend-option");
-      CmdArgs.push_back("-arm-long-calls");
-    }
-
     CmdArgs.push_back("-backend-option");
     CmdArgs.push_back("-arm-strict-align");
 
@@ -4074,17 +4079,6 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     CmdArgs.push_back("-arm-restrict-it");
   }
 
-  if (TT.getArch() == llvm::Triple::arm ||
-      TT.getArch() == llvm::Triple::thumb) {
-    if (Arg *A = Args.getLastArg(options::OPT_mlong_calls,
-                                 options::OPT_mno_long_calls)) {
-      if (A->getOption().matches(options::OPT_mlong_calls)) {
-        CmdArgs.push_back("-backend-option");
-        CmdArgs.push_back("-arm-long-calls");
-      }
-    }
-  }
-
   // Forward -f options with positive and negative forms; we translate
   // these by hand.
   if (Arg *A = Args.getLastArg(options::OPT_fprofile_sample_use_EQ)) {

clang/test/CodeGen/arm-long-calls.c

@@ -0,0 +1,7 @@
+// RUN: %clang_cc1 -triple thumbv7-apple-ios5  -target-feature +long-calls -emit-llvm -o - %s | FileCheck -check-prefix=LONGCALL %s
+// RUN: %clang_cc1 -triple thumbv7-apple-ios5 -emit-llvm -o - %s | FileCheck -check-prefix=NOLONGCALL %s
+
+// LONGCALL: attributes #0 = { {{.*}} "target-features"="+long-calls"
+// NOLONGCALL-NOT: attributes #0 = { {{.*}} "target-features"="+long-calls"
+
+int foo1(int a) { return a; }

clang/test/Driver/apple-kext-mkernel.c

@@ -11,7 +11,7 @@
 // RUN:   -arch armv7 -mkernel -mstrict-align -### -fsyntax-only %s 2> %t
 // RUN: FileCheck --check-prefix=CHECK-ARM < %t %s
 
-// CHECK-ARM: "-backend-option" "-arm-long-calls"
+// CHECK-ARM: "-target-feature" "+long-calls"
 // CHECK-ARM: "-backend-option" "-arm-strict-align"
 // CHECK-ARM-NOT: "-backend-option" "-arm-strict-align"
 // CHECK-ARM: "-fno-builtin"

clang/test/Driver/arm-long-calls.c

@@ -7,9 +7,9 @@
 // RUN: %clang -target armv7-eabi -### -mlong-calls -mno-long-calls %s 2>&1 \
 // RUN:    | FileCheck %s -check-prefix CHECK-NO-LONG-CALLS
 
-// CHECK-DEFAULT-NOT: "-backend-option" "-arm-long-calls"
+// CHECK-DEFAULT-NOT: "-target-feature" "+long-calls"
 
-// CHECK-LONG-CALLS: "-backend-option" "-arm-long-calls"
+// CHECK-LONG-CALLS: "-target-feature" "+long-calls"
 
-// CHECK-NO-LONG-CALLS-NOT: "-backend-option" "-arm-long-calls"
+// CHECK-NO-LONG-CALLS-NOT: "-target-feature" "+long-calls"