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authorGravatar Adam Cozzette <acozzette@google.com>2017-03-28 09:21:13 -0700
committerGravatar Adam Cozzette <acozzette@google.com>2017-03-28 09:45:14 -0700
commitf316375a9531241c73988c9b56aa05f4ac8c5261 (patch)
tree13f24bb2c6c5e72d33432c4961d35fded4753bf7
parentb3f3e123aade1550f3d862d742ab26192cd3b786 (diff)
Added a workaround to allow building for NaCl
arm-nacl-clang seems to produce a mysterious compiler error when it encounters __builtin_clzll, so when we are building for NaCl, let's avoid that in favor of the portable implementation of Log2FloorNonZero64.
-rw-r--r--src/google/protobuf/stubs/port.h9
1 files changed, 8 insertions, 1 deletions
diff --git a/src/google/protobuf/stubs/port.h b/src/google/protobuf/stubs/port.h
index 6f0633c4..6ec5e001 100644
--- a/src/google/protobuf/stubs/port.h
+++ b/src/google/protobuf/stubs/port.h
@@ -44,6 +44,8 @@
#include <stdint.h>
#endif
+#include <google/protobuf/stubs/platform_macros.h>
+
#undef PROTOBUF_LITTLE_ENDIAN
#ifdef _WIN32
// Assuming windows is always little-endian.
@@ -359,7 +361,12 @@ class Bits {
}
static uint32 Log2FloorNonZero64(uint64 n) {
-#if defined(__GNUC__)
+ // arm-nacl-clang runs into an instruction-selection failure when it
+ // encounters __builtin_clzll:
+ // https://bugs.chromium.org/p/nativeclient/issues/detail?id=4395
+ // To work around this, when we build for NaCl we use the portable
+ // implementation instead.
+#if defined(__GNUC__) && !defined(GOOGLE_PROTOBUF_OS_NACL)
return 63 ^ __builtin_clzll(n);
#else
return Log2FloorNonZero64_Portable(n);