r289744 - Use PIC relocation mode by default for PowerPC64 ELF

[Joerg Sonnenberger via cfe-commits]

Author: joerg
Date: Wed Dec 14 18:02:57 2016
New Revision: 289744

URL: http://llvm.org/viewvc/llvm-project?rev=289744&view=rev
Log:
Use PIC relocation mode by default for PowerPC64 ELF

Most of the PowerPC64 code generation already creates PIC access. This
changes to a full PIC default, similar to what GCC is doing.

Overall, a monolithic clang binary shrinks by 600KB (about 1%). This can
be a slight regression for TLS access and will use the TOC more
aggressively instead of synthesizing immediates. It is expected to be
performance neutral.

Differential Revision: https://reviews.llvm.org/D26564

Modified:
    cfe/trunk/lib/Driver/ToolChains.cpp
    cfe/trunk/test/Driver/ppc-abi.c

Modified: cfe/trunk/lib/Driver/ToolChains.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Driver/ToolChains.cpp?rev=289744&r1=289743&r2=289744&view=diff
==============================================================================
--- cfe/trunk/lib/Driver/ToolChains.cpp (original)
+++ cfe/trunk/lib/Driver/ToolChains.cpp Wed Dec 14 18:02:57 2016
@@ -2879,7 +2879,15 @@ bool Generic_GCC::IsUnwindTablesDefault(
 }
 
 bool Generic_GCC::isPICDefault() const {
-  return getArch() == llvm::Triple::x86_64 && getTriple().isOSWindows();
+  switch (getArch()) {
+  case llvm::Triple::x86_64:
+    return getTriple().isOSWindows();
+  case llvm::Triple::ppc64:
+  case llvm::Triple::ppc64le:
+    return !getTriple().isOSBinFormatMachO() && !getTriple().isMacOSX();
+  default:
+    return false;
+  }
 }
 
 bool Generic_GCC::isPIEDefault() const { return false; }

Modified: cfe/trunk/test/Driver/ppc-abi.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Driver/ppc-abi.c?rev=289744&r1=289743&r2=289744&view=diff
==============================================================================
--- cfe/trunk/test/Driver/ppc-abi.c (original)
+++ cfe/trunk/test/Driver/ppc-abi.c Wed Dec 14 18:02:57 2016
@@ -24,7 +24,10 @@
 // RUN: %clang -target powerpc64le-unknown-linux-gnu %s -### -o %t.o 2>&1 \
 // RUN:   -mabi=altivec | FileCheck -check-prefix=CHECK-ELFv2 %s
 
+// CHECK-ELFv1: "-mrelocation-model" "pic" "-pic-level" "2"
 // CHECK-ELFv1: "-target-abi" "elfv1"
+// CHECK-ELFv1-QPX: "-mrelocation-model" "pic" "-pic-level" "2"
 // CHECK-ELFv1-QPX: "-target-abi" "elfv1-qpx"
+// CHECK-ELFv2: "-mrelocation-model" "pic" "-pic-level" "2"
 // CHECK-ELFv2: "-target-abi" "elfv2"