[PATCH] D31813: [ARM] Add hardware build attributes in assembler

[Oliver Stannard via Phabricator via llvm-commits]

olista01 created this revision.
Herald added a subscriber: aemerson.

This passes an option to the ARM assembly parser to emit build
attributes for the hardware selected by command line options, when
assembling an assembly file.

This is not enabled for C/C++, as this would result in duplicate build
attribute directives being emitted in each inline assembly block, when
emitting assembly.

This also adds an option to allow disabling this behaviour for assembly
files, for users who were relying on the old behaviour.

The LLVM part of this is at https://reviews.llvm.org/D31812.


Repository:
  rL LLVM

https://reviews.llvm.org/D31813

Files:
  include/clang/Driver/Options.td
  lib/Driver/ToolChains/Clang.cpp
  test/Driver/arm-default-build-attributes.s


Index: test/Driver/arm-default-build-attributes.s
===================================================================
--- /dev/null
+++ test/Driver/arm-default-build-attributes.s
@@ -0,0 +1,20 @@
+// Enabled by default for assembly
+// RUN: %clang -target armv7--none-eabi -### %s 2>&1 \
+// RUN:    | FileCheck %s -check-prefix CHECK-ENABLED
+
+// Can be forced on or off for assembly.
+// RUN: %clang -target armv7--none-eabi -### %s 2>&1 -mno-default-build-attributes \
+// RUN:    | FileCheck %s -check-prefix CHECK-DISABLED
+// RUN: %clang -target armv7--none-eabi -### %s 2>&1 -mdefault-build-attributes \
+// RUN:    | FileCheck %s -check-prefix CHECK-ENABLED
+
+// Option ignored C/C++ (since we always emit hardware and ABI build attributes
+// during codegen).
+// RUN: %clang -target armv7--none-eabi -### -x c %s -mdefault-build-attributes -verify 2>&1 \
+// RUN:    | FileCheck %s -check-prefix CHECK-DISABLED
+// RUN: %clang -target armv7--none-eabi -### -x c++ %s -mdefault-build-attributes -verify 2>&1 \
+// RUN:    | FileCheck %s -check-prefix CHECK-DISABLED
+
+// CHECK-DISABLED-NOT: "-arm-add-build-attributes"
+// CHECK-ENABLED: "-arm-add-build-attributes"
+// expected-warning {{argument unused during compilation: '-mno-default-build-attributes'}}
Index: lib/Driver/ToolChains/Clang.cpp
===================================================================
--- lib/Driver/ToolChains/Clang.cpp
+++ lib/Driver/ToolChains/Clang.cpp
@@ -4996,6 +4996,19 @@
   case llvm::Triple::x86_64:
     AddX86TargetArgs(Args, CmdArgs);
     break;
+
+  case llvm::Triple::arm:
+  case llvm::Triple::armeb:
+  case llvm::Triple::thumb:
+  case llvm::Triple::thumbeb:
+    // This isn't in AddARMTargetArgs because we want to do this for assembly
+    // only, not C/C++.
+    if (Args.hasFlag(options::OPT_mdefault_build_attributes,
+                     options::OPT_mno_default_build_attributes, true)) {
+        CmdArgs.push_back("-mllvm");
+        CmdArgs.push_back("-arm-add-build-attributes");
+    }
+    break;
   }
 
   // Consume all the warning flags. Usually this would be handled more
Index: include/clang/Driver/Options.td
===================================================================
--- include/clang/Driver/Options.td
+++ include/clang/Driver/Options.td
@@ -1629,6 +1629,8 @@
 def masm_EQ : Joined<["-"], "masm=">, Group<m_Group>, Flags<[DriverOption]>;
 def mcmodel_EQ : Joined<["-"], "mcmodel=">, Group<m_Group>;
 def mimplicit_it_EQ : Joined<["-"], "mimplicit-it=">, Group<m_Group>;
+def mdefault_build_attributes : Joined<["-"], "mdefault-build-attributes">, Group<m_Group>;
+def mno_default_build_attributes : Joined<["-"], "mno-default-build-attributes">, Group<m_Group>;
 def mconstant_cfstrings : Flag<["-"], "mconstant-cfstrings">, Group<clang_ignored_m_Group>;
 def mconsole : Joined<["-"], "mconsole">, Group<m_Group>, Flags<[DriverOption]>;
 def mwindows : Joined<["-"], "mwindows">, Group<m_Group>, Flags<[DriverOption]>;


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