[PATCH] D22461: [ARM] Add support for tlsldm operator to llvm-mc

[Peter Smith via llvm-commits]

peter.smith created this revision.
peter.smith added reviewers: rengolin, t.p.northover.
peter.smith added a subscriber: llvm-commits.
Herald added subscribers: rengolin, aemerson.

The standard local dynamic model for TLS on ARM systems needs two relocations for each data access:
- R_ARM_TLS_LDM32 (module idx)
- R_ARM_TLS_LDO32 (offset of object from origin of module TLS block)
    
In GNU style assembler we use symbol(tlsldm) and symbol(tlsldo) to produce these relocations.
    
llvm-mc for ARM supports symbol(tlsldo) but does not support symbol(tlsldm). This patch wires up the existing symbol(tlsldm) support in the assembler to the R_ARM_TLS_LDM32 relocation.

This change is for llvm-mc only, it does not implement lowering of generated TLS code to local-dynamic (-mtls-model=local-dynamic). 
    
TLS for ARM is defined in Addenda to, and Errata in, the ABI for the ARM Architecture


https://reviews.llvm.org/D22461

Files:
  lib/Target/ARM/MCTargetDesc/ARMELFObjectWriter.cpp
  test/MC/ARM/symbol-variants.s

Index: test/MC/ARM/symbol-variants.s
===================================================================
--- test/MC/ARM/symbol-variants.s
+++ test/MC/ARM/symbol-variants.s
@@ -90,8 +90,14 @@
 @CHECK: 68 R_ARM_PREL31 f26
 @CHECK: 6c R_ARM_PREL31 f27
 
+@ tlsldm
+.word f28(TLSLDM)
+.word f29(tlsldm)
+ at CHECK: 70 R_ARM_TLS_LDM32 f28
+ at CHECK: 74 R_ARM_TLS_LDM32 f29
+
 @ got_prel
-.word	f28(GOT_PREL) + (. - .Lsym)
-	ldr r3, =f29(GOT_PREL)
-@ CHECK: 70 R_ARM_GOT_PREL f28
-@ CHECK: 78 R_ARM_GOT_PREL f29
+.word	f30(GOT_PREL) + (. - .Lsym)
+	ldr r3, =f31(GOT_PREL)
+@ CHECK: 78 R_ARM_GOT_PREL f30
+@ CHECK: 80 R_ARM_GOT_PREL f31
Index: lib/Target/ARM/MCTargetDesc/ARMELFObjectWriter.cpp
===================================================================
--- lib/Target/ARM/MCTargetDesc/ARMELFObjectWriter.cpp
+++ lib/Target/ARM/MCTargetDesc/ARMELFObjectWriter.cpp
@@ -221,6 +221,9 @@
       case MCSymbolRefExpr::VK_TLSDESC:
         Type = ELF::R_ARM_TLS_GOTDESC;
         break;
+      case MCSymbolRefExpr::VK_TLSLDM:
+        Type = ELF::R_ARM_TLS_LDM32;
+        break;
       case MCSymbolRefExpr::VK_ARM_TLSDESCSEQ:
         Type = ELF::R_ARM_TLS_DESCSEQ;
         break;


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D22461.64311.patch
Type: text/x-patch
Size: 1177 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20160718/34a997fe/attachment.bin>