Merging r227062:

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r227062 | rengolin | 2015-01-25 15:17:48 -0800 (Sun, 25 Jan 2015) | 10 lines

Allows Clang to use LLVM's fixes-x18 option

This patch allows clang to have llvm reserve the x18
platform register on AArch64. FreeBSD will use this in the kernel for
per-cpu data but has no need to reserve this register in userland so
will need this flag to reserve it.

This uses llvm r226664 to allow this register to be reserved.

Patch by Andrew Turner.
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git-svn-id: https://llvm.org/svn/llvm-project/cfe/branches/release_36@227151 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/Driver/Options.td b/include/clang/Driver/Options.td
index 4daddba332d7ac63623c79f00e77f6c7e68c2c72..b68a46bad84bf8ba40c380a2f29354f543047475 100644 (file)
--- a/include/clang/Driver/Options.td
+++ b/include/clang/Driver/Options.td
@@ -1209,6 +1209,8 @@ def mfix_cortex_a53_835769 : Flag<["-"], "mfix-cortex-a53-835769">,
 def mno_fix_cortex_a53_835769 : Flag<["-"], "mno-fix-cortex-a53-835769">,
   Group<m_aarch64_Features_Group>,
   HelpText<"Don't workaround Cortex-A53 erratum 835769 (AArch64 only)">;
+def ffixed_x18 : Flag<["-"], "ffixed-x18">, Group<m_aarch64_Features_Group>,
+  HelpText<"Reserve the x18 register (AArch64 only)">;
 
 def mvsx : Flag<["-"], "mvsx">, Group<m_ppc_Features_Group>;
 def mno_vsx : Flag<["-"], "mno-vsx">, Group<m_ppc_Features_Group>;

diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index d625c0e3e2f674afb3fd49143366810c4b6aa928..810a4d7caada29070d9527f9b071b0c54fc59267 100644 (file)
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -958,6 +958,11 @@ void Clang::AddAArch64TargetArgs(const ArgList &Args,
     if (A->getOption().matches(options::OPT_mno_global_merge))
       CmdArgs.push_back("-mno-global-merge");
   }
+
+  if (Args.hasArg(options::OPT_ffixed_x18)) {
+    CmdArgs.push_back("-backend-option");
+    CmdArgs.push_back("-aarch64-reserve-x18");
+  }
 }
 
 // Get CPU and ABI names. They are not independent

diff --git a/test/Driver/aarch64-fixed-x18.c b/test/Driver/aarch64-fixed-x18.c
new file mode 100644 (file)
index 0000000..35d0caf
--- /dev/null
+++ b/test/Driver/aarch64-fixed-x18.c
@@ -0,0 +1,4 @@
+// RUN: %clang -target aarch64-none-gnu -ffixed-x18 -### %s 2> %t
+// RUN: FileCheck --check-prefix=CHECK-FIXED-X18 < %t %s
+
+// CHECK-FIXED-X18: "-backend-option" "-aarch64-reserve-x18"