[compiler-rt] Enable ASAN for powerpc64le-linux

[Peter Bergner]

The following patch gets ASAN somewhat working on powerpc64le-linux.
It currently assumes the LE kernel uses 46-bit addressing, which is
true, but it doesn't solve the case for BE where it may be 44 or
46 bits.  That can be fixed with a follow on patch.

There are some test suite fails even with this patch that I haven't had
time to solve yet, but this is better than the state it is in now.
The limited debugging of those test suite fails seems to show that the
address map for 46-bit addressing has changed and so we'll need to
modify the shadow memory location slightly.  Again, that can be fixed
with a follow on patch.

Is this ok to commit?

Peter


Index: lib/asan/asan_mapping.h
===================================================================
--- lib/asan/asan_mapping.h	(revision 219685)
+++ lib/asan/asan_mapping.h	(working copy)
@@ -87,7 +87,11 @@
 static const u64 kDefaultShort64bitShadowOffset = 0x7FFF8000;  // < 2G.
 static const u64 kAArch64_ShadowOffset64 = 1ULL << 36;
 static const u64 kMIPS32_ShadowOffset32 = 0x0aaa8000;
+#if defined(__powerpc64__) && defined (__BIG_ENDIAN__)
 static const u64 kPPC64_ShadowOffset64 = 1ULL << 41;
+#elif defined(__powerpc64__) && defined (__LITTLE_ENDIAN__)
+static const u64 kPPC64_ShadowOffset64 = 1ULL << 43;
+#endif
 static const u64 kFreeBSD_ShadowOffset32 = 1ULL << 30;  // 0x40000000
 static const u64 kFreeBSD_ShadowOffset64 = 1ULL << 46;  // 0x400000000000
 
Index: lib/asan/asan_report.cc
===================================================================
--- lib/asan/asan_report.cc	(revision 219685)
+++ lib/asan/asan_report.cc	(working copy)
@@ -437,8 +437,8 @@
   // especially given that the alloca may be from entirely different place
   // (e.g. use-after-scope, or different thread's stack).
   StackTrace alloca_stack;
-#ifdef __powerpc64__
-  // On PowerPC64, the address of a function actually points to a
+#if defined(__powerpc64__) and defined(__BIG_ENDIAN__)
+  // On PowerPC64 ELFv1, the address of a function actually points to a
   // three-doubleword data structure with the first field containing
   // the address of the function's code.
   access.frame_pc = *reinterpret_cast<uptr *>(access.frame_pc);
Index: lib/sanitizer_common/sanitizer_posix.cc
===================================================================
--- lib/sanitizer_common/sanitizer_posix.cc	(revision 219685)
+++ lib/sanitizer_common/sanitizer_posix.cc	(working copy)
@@ -78,7 +78,7 @@
 
 uptr GetMaxVirtualAddress() {
 #if SANITIZER_WORDSIZE == 64
-# if defined(__powerpc64__)
+# if defined(__powerpc64__) && defined(__BIG_ENDIAN__)
   // On PowerPC64 we have two different address space layouts: 44- and 46-bit.
   // We somehow need to figure out which one we are using now and choose
   // one of 0x00000fffffffffffUL and 0x00003fffffffffffUL.
@@ -85,6 +85,8 @@
   // Note that with 'ulimit -s unlimited' the stack is moved away from the top
   // of the address space, so simply checking the stack address is not enough.
   return (1ULL << 44) - 1;  // 0x00000fffffffffffUL
+# elif defined(__powerpc64__) && defined(__LITTLE_ENDIAN__)
+  return (1ULL << 46) - 1;  // 0x00003fffffffffffUL
 # elif defined(__aarch64__)
   return (1ULL << 39) - 1;
 # else
Index: lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cc
===================================================================
--- lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cc	(revision 219685)
+++ lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cc	(working copy)
@@ -341,8 +341,10 @@
     const char* const kSymbolizerArch = "--default-arch=x86_64";
 #elif defined(__i386__)
     const char* const kSymbolizerArch = "--default-arch=i386";
-#elif defined(__powerpc64__)
+#elif defined(__powerpc64__) && defined(__BIG_ENDIAN__)
     const char* const kSymbolizerArch = "--default-arch=powerpc64";
+#elif defined(__powerpc64__) && defined(__LITTLE_ENDIAN__)
+    const char* const kSymbolizerArch = "--default-arch=powerpc64le";
 #else
     const char* const kSymbolizerArch = "--default-arch=unknown";
 #endif