[PowerPC] Default ppc64 linux-gnu/freebsd to -fno-PIC

According to D53384, the default was switched from -fno-PIC to -fPIC to
work around a -fsanitize=leak bug on big-endian.

This gratuitous difference between little-endian and big-endian is
undesired, and not acceptable on powerpc64-unknown-freebsd.  If
-fsanitize=leak still has the problem, we should consider defaulting to
-fPIC/-fPIE only when -fsanitize=leak is specified (see SanitizerArgs::requiresPIE())

powerpc64-ibm-aix is unaffected: it still defaults to -fPIC.
powerpc64-linux-musl is unaffected (-fPIE since D39588): it still defaults to -fPIE.

Reviewed By: #powerpc, jhibbits

Differential Revision: https://reviews.llvm.org/D72363

clang/lib/Driver/ToolChains/Gnu.cpp

@@ -2615,9 +2615,6 @@ bool Generic_GCC::isPICDefault() const {
   switch (getArch()) {
   case llvm::Triple::x86_64:
     return getTriple().isOSWindows();
-  case llvm::Triple::ppc64:
-    // Big endian PPC is PIC by default
-    return !getTriple().isOSBinFormatMachO() && !getTriple().isMacOSX();
   case llvm::Triple::mips64:
   case llvm::Triple::mips64el:
     return true;

clang/test/Driver/ppc-abi.c

@@ -28,18 +28,20 @@
 // RUN: %clang -target powerpc64-unknown-freebsd12 %s -### 2>&1 | FileCheck --check-prefix=CHECK-ELFv1 %s
 // RUN: %clang -target powerpc64-unknown-freebsd13 %s -### 2>&1 | FileCheck --check-prefix=CHECK-ELFv2-BE %s
 // RUN: %clang -target powerpc64-unknown-freebsd14 %s -### 2>&1 | FileCheck --check-prefix=CHECK-ELFv2-BE %s
-// RUN: %clang -target powerpc64-linux-musl %s -### 2>&1 | FileCheck --check-prefix=CHECK-ELFv2-BE %s
+// RUN: %clang -target powerpc64-linux-musl %s -### 2>&1 | FileCheck --check-prefix=CHECK-ELFv2-BE-PIE %s
 
-// CHECK-ELFv1: "-mrelocation-model" "pic" "-pic-level" "2"
+// CHECK-ELFv1: "-mrelocation-model" "static"
 // CHECK-ELFv1: "-target-abi" "elfv1"
 // CHECK-ELFv1-LE: "-mrelocation-model" "static"
 // CHECK-ELFv1-LE: "-target-abi" "elfv1"
-// CHECK-ELFv1-QPX: "-mrelocation-model" "pic" "-pic-level" "2"
+// CHECK-ELFv1-QPX: "-mrelocation-model" "static"
 // CHECK-ELFv1-QPX: "-target-abi" "elfv1-qpx"
 // CHECK-ELFv2: "-mrelocation-model" "static"
 // CHECK-ELFv2: "-target-abi" "elfv2"
-// CHECK-ELFv2-BE: "-mrelocation-model" "pic" "-pic-level" "2"
+// CHECK-ELFv2-BE: "-mrelocation-model" "static"
 // CHECK-ELFv2-BE: "-target-abi" "elfv2"
+// CHECK-ELFv2-BE-PIE: "-mrelocation-model" "pic" "-pic-level" "2" "-pic-is-pie"
+// CHECK-ELFv2-BE-PIE: "-target-abi" "elfv2"
 
 // RUN: %clang -fPIC -target powerpc64-unknown-linux-gnu %s -### -o %t.o 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-ELFv1-PIC %s