Contribution of PowerPC port (continuation of 422063005)

src/base/platform/platform-posix.cc

Index: src/base/platform/platform-posix.cc
diff --git a/src/base/platform/platform-posix.cc b/src/base/platform/platform-posix.cc
index c2fa26a9ea9364b8009e7b5d4b2a0b290e06a64b..9f71c905d66d22d037bc8478c3bec20f6a5aa20c 100644
--- a/src/base/platform/platform-posix.cc
+++ b/src/base/platform/platform-posix.cc
@@ -85,8 +85,8 @@ int OS::ActivationFrameAlignment() {
   // Otherwise we just assume 16 byte alignment, i.e.:
   // - With gcc 4.4 the tree vectorization optimizer can generate code
   //   that requires 16 byte alignment such as movdqa on x86.
-  // - Mac OS X and Solaris (64-bit) activation frames must be 16 byte-aligned;
-  //   see "Mac OS X ABI Function Call Guide"
+  // - Mac OS X, PPC and Solaris (64-bit) activation frames must
+  //   be 16 byte-aligned;  see "Mac OS X ABI Function Call Guide"
   return 16;
 #endif
 }
@@ -171,6 +171,14 @@ void* OS::GetRandomMmapAddr() {
   // the hint address to 46 bits to give the kernel a fighting chance of
   // fulfilling our placement request.
   raw_addr &= V8_UINT64_C(0x3ffffffff000);
+#elif V8_TARGET_ARCH_PPC64
+#if V8_TARGET_BIG_ENDIAN
+  // Big-endian Linux: 44 bits of virtual addressing.
+  raw_addr &= V8_UINT64_C(0x03fffffff000);
+#else
+  // Little-endian Linux: 48 bits of virtual addressing.
+  raw_addr &= V8_UINT64_C(0x3ffffffff000);
+#endif
 #else
   raw_addr &= 0x3ffff000;
 
@@ -225,6 +233,8 @@ void OS::DebugBreak() {
   asm("break");
 #elif V8_HOST_ARCH_MIPS64
   asm("break");
+#elif V8_HOST_ARCH_PPC
+  asm("twge 2,2");
 #elif V8_HOST_ARCH_IA32
 #if V8_OS_NACL
   asm("hlt");