[ARM] Emit ABI_PCS_R9_use build attribute.

Patch by Ben Foster!

Differential Revision: http://reviews.llvm.org/D4657

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213944 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/Support/ARMBuildAttributes.h b/include/llvm/Support/ARMBuildAttributes.h
index f63e0a61f6390b8e265577638b35dd968ae5a9b5..852523fc9bf5db1c83ee0de55df9566b04cd1e04 100644 (file)
--- a/include/llvm/Support/ARMBuildAttributes.h
+++ b/include/llvm/Support/ARMBuildAttributes.h
@@ -146,6 +146,12 @@ enum {
   AllowNeon2 = 2,     // SIMDv2 was permitted (Half-precision FP, MAC operations)
   AllowNeonARMv8 = 3, // ARM v8-A SIMD was permitted
 
+  // Tag_ABI_PCS_R9_use, (=14), uleb128
+  R9IsGPR = 0,        // R9 used as v6 (just another callee-saved register)
+  R9IsSB = 1,         // R9 used as a global static base rgister
+  R9IsTLSPointer = 2, // R9 used as a thread local storage pointer
+  R9Reserved = 3,     // R9 not used by code associated with attributed entity
+
   // Tag_ABI_PCS_RW_data, (=15), uleb128
   AddressRWPCRel = 1, // Address RW static data PC-relative
   AddressRWSBRel = 2, // Address RW static data SB-relative

diff --git a/lib/Target/ARM/ARMAsmPrinter.cpp b/lib/Target/ARM/ARMAsmPrinter.cpp
index 9ad808c00e799694b5bfc414ef65aa65aabab6bc..0ef72928926e07a4a6432f73bc67a71e17f2fa40 100644 (file)
--- a/lib/Target/ARM/ARMAsmPrinter.cpp
+++ b/lib/Target/ARM/ARMAsmPrinter.cpp
@@ -760,6 +760,17 @@ void ARMAsmPrinter::emitAttributes() {
     }
   }
 
+  // TODO: We currently only support either reserving the register, or treating
+  // it as another callee-saved register, but not as SB or a TLS pointer; It
+  // would instead be nicer to push this from the frontend as metadata, as we do
+  // for the wchar and enum size tags
+  if (Subtarget->isR9Reserved())
+      ATS.emitAttribute(ARMBuildAttrs::ABI_PCS_R9_use,
+                        ARMBuildAttrs::R9Reserved);
+  else
+      ATS.emitAttribute(ARMBuildAttrs::ABI_PCS_R9_use,
+                        ARMBuildAttrs::R9IsGPR);
+
   if (Subtarget->hasTrustZone() && Subtarget->hasVirtualization())
       ATS.emitAttribute(ARMBuildAttrs::Virtualization_use,
                         ARMBuildAttrs::AllowTZVirtualization);

diff --git a/test/CodeGen/ARM/build-attributes.ll b/test/CodeGen/ARM/build-attributes.ll
index d75d55d0fa68805cbd41bcc6f8df4ccee788ec69..a4b77c80c104a0860d92a4401f9dca8569a9d380 100644 (file)
--- a/test/CodeGen/ARM/build-attributes.ll
+++ b/test/CodeGen/ARM/build-attributes.ll
@@ -38,6 +38,8 @@
 ; RUN: llc < %s -mtriple=arm-none-linux-gnueabi -relocation-model=default | FileCheck %s --check-prefix=RELOC-OTHER
 ; RUN: llc < %s -mtriple=arm-none-linux-gnueabi -relocation-model=dynamic-no-pic | FileCheck %s --check-prefix=RELOC-OTHER
 ; RUN: llc < %s -mtriple=arm-none-linux-gnueabi | FileCheck %s --check-prefix=RELOC-OTHER
+; RUN: llc < %s -mtriple=arm-none-linux-gnueabi | FileCheck %s --check-prefix=PCS-R9-USE
+; RUN: llc < %s -mtriple=arm-none-linux-gnueabi -arm-reserve-r9 | FileCheck %s --check-prefix=PCS-R9-RESERVE
 
 ; XSCALE:      .eabi_attribute 6, 5
 ; XSCALE:      .eabi_attribute 8, 1
@@ -463,6 +465,9 @@
 ; RELOC-PIC:  .eabi_attribute 17, 2
 ; RELOC-OTHER:  .eabi_attribute 17, 1
 
+; PCS-R9-USE:  .eabi_attribute 14, 0
+; PCS-R9-RESERVE:  .eabi_attribute 14, 3
+
 define i32 @f(i64 %z) {
        ret i32 0
 }