[PATCH] D72479: [PowerPC][AIX] Make PIC the default relocation model for AIX

[Steven Wan via Phabricator via llvm-commits]

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The `llc` tool currently defaults to Static relocation model and generates non-relocatable code for 32-bit Power. This is not desirable on AIX where we always generate Position Independent Code (PIC). This patch makes PIC the default relocation model for AIX.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D72479

Files:
  llvm/lib/Target/PowerPC/PPCTargetMachine.cpp
  llvm/test/CodeGen/PowerPC/aix-pic-default.ll


Index: llvm/test/CodeGen/PowerPC/aix-pic-default.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/PowerPC/aix-pic-default.ll
@@ -0,0 +1,19 @@
+; RUN: llc -verify-machineinstrs -mcpu=pwr4 -mtriple powerpc-ibm-aix-xcoff < %s | FileCheck %s
+; RUN: llc -verify-machineinstrs -mcpu=pwr4 -mtriple powerpc64-ibm-aix-xcoff < %s | FileCheck --check-prefix=CHECK64 %s
+
+ at a = common global i32 0
+ at b = constant i32* @a
+
+;CHECK:         .comm   a[RW],4,2
+;CHECK-NEXT:    .csect .data[RW]
+;CHECK-NEXT:    .globl  b
+;CHECK-NEXT:    .align  2
+;CHECK-NEXT: b:
+;CHECK-NEXT:    .long   a
+
+;CHECK64:       .comm   a[RW],4,2
+;CHECK64-NEXT:  .csect .data[RW]
+;CHECK64-NEXT:  .globl  b
+;CHECK64-NEXT:  .align  3
+;CHECK64-NEXT: b:
+;CHECK64-NEXT:  .llong  a
Index: llvm/lib/Target/PowerPC/PPCTargetMachine.cpp
===================================================================
--- llvm/lib/Target/PowerPC/PPCTargetMachine.cpp
+++ llvm/lib/Target/PowerPC/PPCTargetMachine.cpp
@@ -230,8 +230,8 @@
   if (TT.isOSDarwin())
     return Reloc::DynamicNoPIC;
 
-  // Big Endian PPC is PIC by default.
-  if (TT.getArch() == Triple::ppc64)
+  // Big Endian PPC and AIX default to PIC.
+  if (TT.getArch() == Triple::ppc64 || TT.isOSAIX())
     return Reloc::PIC_;
 
   // Rest are static by default.


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