Fix endianness issues in absl/random

3 files changed, 246 insertions, 1 deletions

diff --git a/debian/changelog b/debian/changelog
index 664d5007..caa82188 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,7 +1,7 @@
 abseil (0~20200923.3-1) UNRELEASED; urgency=medium
 
   * New upstream release.
-  * Correct endianness issues in hash functions.
+  * Correct endianness issues in hash functions and RNG.
 
  -- Benjamin Barenblat <bbaren@debian.org>  Thu, 04 Feb 2021 12:08:46 -0500
 
diff --git a/debian/patches/endian-random.diff b/debian/patches/endian-random.diff
new file mode 100644
index 00000000..244f36df
--- /dev/null
+++ b/debian/patches/endian-random.diff
@@ -0,0 +1,244 @@
+From: Benjamin Barenblat <bbaren@google.com>
+Subject: Remove endian-sensitivity from Abseil's RNG
+Forwarded: yes
+
+Ensure that the Abseil random number generator produces identical output
+on both big- and little-endian platforms by byte-swapping appropriately
+on big-endian systems.
+
+--- a/absl/base/BUILD.bazel
++++ b/absl/base/BUILD.bazel
+@@ -479,6 +479,7 @@
+     copts = ABSL_DEFAULT_COPTS,
+     linkopts = ABSL_DEFAULT_LINKOPTS,
+     deps = [
++        ":base",
+         ":config",
+         ":core_headers",
+     ],
+--- a/absl/base/CMakeLists.txt
++++ b/absl/base/CMakeLists.txt
+@@ -418,6 +418,7 @@
+   COPTS
+     ${ABSL_DEFAULT_COPTS}
+   DEPS
++    absl::base
+     absl::config
+     absl::core_headers
+   PUBLIC
+--- a/absl/base/internal/endian.h
++++ b/absl/base/internal/endian.h
+@@ -26,6 +26,7 @@
+ #endif
+ 
+ #include <cstdint>
++#include "absl/base/casts.h"
+ #include "absl/base/config.h"
+ #include "absl/base/internal/unaligned_access.h"
+ #include "absl/base/port.h"
+@@ -173,6 +174,36 @@
+ 
+ #endif /* ENDIAN */
+ 
++inline uint8_t FromHost(uint8_t x) { return x; }
++inline uint16_t FromHost(uint16_t x) { return FromHost16(x); }
++inline uint32_t FromHost(uint32_t x) { return FromHost32(x); }
++inline uint64_t FromHost(uint64_t x) { return FromHost64(x); }
++inline uint8_t ToHost(uint8_t x) { return x; }
++inline uint16_t ToHost(uint16_t x) { return ToHost16(x); }
++inline uint32_t ToHost(uint32_t x) { return ToHost32(x); }
++inline uint64_t ToHost(uint64_t x) { return ToHost64(x); }
++
++inline int8_t FromHost(int8_t x) { return x; }
++inline int16_t FromHost(int16_t x) {
++  return bit_cast<int16_t>(FromHost16(bit_cast<uint16_t>(x)));
++}
++inline int32_t FromHost(int32_t x) {
++  return bit_cast<int32_t>(FromHost32(bit_cast<uint32_t>(x)));
++}
++inline int64_t FromHost(int64_t x) {
++  return bit_cast<int64_t>(FromHost64(bit_cast<uint64_t>(x)));
++}
++inline int8_t ToHost(int8_t x) { return x; }
++inline int16_t ToHost(int16_t x) {
++  return bit_cast<int16_t>(ToHost16(bit_cast<uint16_t>(x)));
++}
++inline int32_t ToHost(int32_t x) {
++  return bit_cast<int32_t>(ToHost32(bit_cast<uint32_t>(x)));
++}
++inline int64_t ToHost(int64_t x) {
++  return bit_cast<int64_t>(ToHost64(bit_cast<uint64_t>(x)));
++}
++
+ // Functions to do unaligned loads and stores in little-endian order.
+ inline uint16_t Load16(const void *p) {
+   return ToHost16(ABSL_INTERNAL_UNALIGNED_LOAD16(p));
+@@ -233,6 +264,36 @@
+ 
+ #endif /* ENDIAN */
+ 
++inline uint8_t FromHost(uint8_t x) { return x; }
++inline uint16_t FromHost(uint16_t x) { return FromHost16(x); }
++inline uint32_t FromHost(uint32_t x) { return FromHost32(x); }
++inline uint64_t FromHost(uint64_t x) { return FromHost64(x); }
++inline uint8_t ToHost(uint8_t x) { return x; }
++inline uint16_t ToHost(uint16_t x) { return ToHost16(x); }
++inline uint32_t ToHost(uint32_t x) { return ToHost32(x); }
++inline uint64_t ToHost(uint64_t x) { return ToHost64(x); }
++
++inline int8_t FromHost(int8_t x) { return x; }
++inline int16_t FromHost(int16_t x) {
++  return bit_cast<int16_t>(FromHost16(bit_cast<uint16_t>(x)));
++}
++inline int32_t FromHost(int32_t x) {
++  return bit_cast<int32_t>(FromHost32(bit_cast<uint32_t>(x)));
++}
++inline int64_t FromHost(int64_t x) {
++  return bit_cast<int64_t>(FromHost64(bit_cast<uint64_t>(x)));
++}
++inline int8_t ToHost(int8_t x) { return x; }
++inline int16_t ToHost(int16_t x) {
++  return bit_cast<int16_t>(ToHost16(bit_cast<uint16_t>(x)));
++}
++inline int32_t ToHost(int32_t x) {
++  return bit_cast<int32_t>(ToHost32(bit_cast<uint32_t>(x)));
++}
++inline int64_t ToHost(int64_t x) {
++  return bit_cast<int64_t>(ToHost64(bit_cast<uint64_t>(x)));
++}
++
+ // Functions to do unaligned loads and stores in big-endian order.
+ inline uint16_t Load16(const void *p) {
+   return ToHost16(ABSL_INTERNAL_UNALIGNED_LOAD16(p));
+--- a/absl/random/CMakeLists.txt
++++ b/absl/random/CMakeLists.txt
+@@ -611,6 +611,7 @@
+     ${ABSL_DEFAULT_LINKOPTS}
+   DEPS
+     absl::config
++    absl::endian
+   TESTONLY
+ )
+ 
+@@ -758,6 +759,7 @@
+   LINKOPTS
+     ${ABSL_DEFAULT_LINKOPTS}
+   DEPS
++    absl::endian
+     absl::random_internal_iostream_state_saver
+     absl::random_internal_randen
+     absl::raw_logging_internal
+@@ -1119,6 +1121,7 @@
+   LINKOPTS
+     ${ABSL_DEFAULT_LINKOPTS}
+   DEPS
++    absl::endian
+     absl::random_internal_randen_slow
+     gtest_main
+ )
+--- a/absl/random/internal/BUILD.bazel
++++ b/absl/random/internal/BUILD.bazel
+@@ -124,7 +124,10 @@
+     ],
+     copts = ABSL_DEFAULT_COPTS,
+     linkopts = ABSL_DEFAULT_LINKOPTS,
+-    deps = ["//absl/base:config"],
++    deps = [
++        "//absl/base:config",
++        "//absl/base:endian",
++    ],
+ )
+ 
+ cc_library(
+@@ -241,6 +244,7 @@
+     deps = [
+         ":iostream_state_saver",
+         ":randen",
++        "//absl/base:endian",
+         "//absl/meta:type_traits",
+     ],
+ )
+@@ -606,6 +610,7 @@
+         ":platform",
+         ":randen_slow",
+         "@com_google_googletest//:gtest_main",
++        "//absl/base:endian",
+     ],
+ )
+ 
+--- a/absl/random/internal/explicit_seed_seq.h
++++ b/absl/random/internal/explicit_seed_seq.h
+@@ -23,6 +23,7 @@
+ #include <vector>
+ 
+ #include "absl/base/config.h"
++#include "absl/base/internal/endian.h"
+ 
+ namespace absl {
+ ABSL_NAMESPACE_BEGIN
+@@ -73,7 +74,7 @@
+   template <typename OutIterator>
+   void generate(OutIterator begin, OutIterator end) {
+     for (size_t index = 0; begin != end; begin++) {
+-      *begin = state_.empty() ? 0 : state_[index++];
++      *begin = state_.empty() ? 0 : little_endian::FromHost32(state_[index++]);
+       if (index >= state_.size()) {
+         index = 0;
+       }
+--- a/absl/random/internal/randen_engine.h
++++ b/absl/random/internal/randen_engine.h
+@@ -23,6 +23,7 @@
+ #include <limits>
+ #include <type_traits>
+ 
++#include "absl/base/internal/endian.h"
+ #include "absl/meta/type_traits.h"
+ #include "absl/random/internal/iostream_state_saver.h"
+ #include "absl/random/internal/randen.h"
+@@ -76,7 +77,7 @@
+       impl_.Generate(state_);
+     }
+ 
+-    return state_[next_++];
++    return little_endian::ToHost(state_[next_++]);
+   }
+ 
+   template <class SeedSequence>
+@@ -181,7 +182,8 @@
+       // In the case that `elem` is `uint8_t`, it must be cast to something
+       // larger so that it prints as an integer rather than a character. For
+       // simplicity, apply the cast all circumstances.
+-      os << static_cast<numeric_type>(elem) << os.fill();
++      os << static_cast<numeric_type>(little_endian::FromHost(elem))
++         << os.fill();
+     }
+     os << engine.next_;
+     return os;
+@@ -200,7 +202,7 @@
+       // necessary to read a wider type and then cast it to uint8_t.
+       numeric_type value;
+       is >> value;
+-      elem = static_cast<result_type>(value);
++      elem = little_endian::ToHost(static_cast<result_type>(value));
+     }
+     is >> next;
+     if (is.fail()) {
+--- a/absl/random/internal/randen_slow_test.cc
++++ b/absl/random/internal/randen_slow_test.cc
+@@ -17,6 +17,7 @@
+ #include <cstring>
+ 
+ #include "gtest/gtest.h"
++#include "absl/base/internal/endian.h"
+ #include "absl/random/internal/randen_traits.h"
+ 
+ namespace {
+@@ -56,7 +57,7 @@
+ 
+   uint64_t* id = d.state;
+   for (const auto& elem : kGolden) {
+-    EXPECT_EQ(elem, *id++);
++    EXPECT_EQ(absl::little_endian::FromHost64(elem), *id++);
+   }
+ }
+ 
diff --git a/debian/patches/series b/debian/patches/series
index 33ae234a..6330dc6c 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -5,3 +5,4 @@ latomic.diff
 cpu-frequency.diff
 nan-narrowing.diff
 endian-hash.diff
+endian-random.diff