Export of internal Abseil changes

--
e54b9c7bbb0c58475676c268e2e19c69f4bce48a by Jorg Brown <jorg@google.com>:

Tweak ABSL_PREDICT_TRUE slightly, for better code on some platforms and/or
optimization levels.  "false || (x)" is more verbose than "!!(x)", but
ultimately more efficient.

For example, given this code:

void InitIfNecessary() {
  if (ABSL_PREDICT_TRUE(NeedsInit())) {
    SlowInitIfNecessary();
  }
}

Clang with default optimization level will produce:

Before this CL              After this CL
InitIfNecessary:            InitIfNecessary:
  push rbp                    push rbp
  mov  rbp, rsp               mov  rbp, rsp
  call NeedsInit              call NeedsInit
  xor  al, -1
  xor  al, -1
  test al, 1                  test al, 1
  jne  .LBB2_1                jne  .LBB3_1
  jmp  .LBB2_2                jmp  .LBB3_2
.LBB2_1:                    .LBB3_1:
  call SlowInitIfNecessary    call SlowInitIfNecessary
.LBB2_2:                    .LBB3_2:
  pop  rbp                    pop  rbp
  ret                         ret
PiperOrigin-RevId: 276401386

--
0a3c4dfd8342bf2b1b11a87f1c662c883f73cab7 by Abseil Team <absl-team@google.com>:

Fix comment nit: sem_open => sem_init.

The code calls sem_init, not sem_open, to initialize an unnamed semaphore.
(sem_open creates or opens a named semaphore.)

PiperOrigin-RevId: 276344072

--
b36a664e9459057509a90e83d3482e1d3a4c44c7 by Abseil Team <absl-team@google.com>:

Fix typo in flat_hash_map.h: exchaged -> exchanged

PiperOrigin-RevId: 276295792

--
7bbd8d18276eb110c8335743e35fceb662ddf3d6 by Samuel Benzaquen <sbenza@google.com>:

Add assertions to verify use of iterators.

PiperOrigin-RevId: 276283300

--
677398a8ffcb1f59182cffe57a4fe7ff147a0404 by Laramie Leavitt <lar@google.com>:

Migrate distribution_impl.h/cc to generate_real.h/cc.

Combine the methods RandU64To<Float,Double> into a single method:
GenerateRealFromBits().

Remove rejection sampling from absl::uniform_real_distribution.

PiperOrigin-RevId: 276158675

--
c60c9d11d24b0c546329d998e78e15a84b3153f5 by Abseil Team <absl-team@google.com>:

Internal change

PiperOrigin-RevId: 276126962

--
4c840cab6a8d86efa29b397cafaf7520eece68cc by Andy Soffer <asoffer@google.com>:

Update CMakeLists.txt to address https://github.com/abseil/abseil-cpp/issues/365.
This does not cover every platform, but it does at least address the
first-order issue of assuming gcc implies x86.

PiperOrigin-RevId: 276116253

--
98da366e6b5d51afe5d7ac6722126aca23d85ee6 by Abseil Team <absl-team@google.com>:

Internal change

PiperOrigin-RevId: 276097452
GitOrigin-RevId: e54b9c7bbb0c58475676c268e2e19c69f4bce48a
Change-Id: I02d84454bb71ab21ad3d39650acf6cc6e36f58d7

1 files changed, 20 insertions, 5 deletions

diff --git a/absl/copts/AbseilConfigureCopts.cmake b/absl/copts/AbseilConfigureCopts.cmake
index b430873c..b4426469 100644
--- a/absl/copts/AbseilConfigureCopts.cmake
+++ b/absl/copts/AbseilConfigureCopts.cmake
@@ -5,10 +5,29 @@ set(ABSL_LSAN_LINKOPTS "")
 set(ABSL_HAVE_LSAN OFF)
 set(ABSL_DEFAULT_LINKOPTS "")
 
+if("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "x86_64")
+  if (MSVC)
+    set(ABSL_RANDOM_RANDEN_COPTS "${ABSL_RANDOM_HWAES_MSVC_X64_FLAGS}")
+  else()
+    set(ABSL_RANDOM_RANDEN_COPTS "${ABSL_RANDOM_HWAES_X64_FLAGS}")
+  endif()
+elseif("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "arm")
+  if ("${CMAKE_SIZEOF_VOID_P}" STREQUAL "8")
+    set(ABSL_RANDOM_RANDEN_COPTS "${ABSL_RANDOM_HWAES_ARM64_FLAGS}")
+  elseif("${CMAKE_SIZEOF_VOID_P}" STREQUAL "4")
+    set(ABSL_RANDOM_RANDEN_COPTS "${ABSL_RANDOM_HWAES_ARM32_FLAGS}")
+  else()
+    message(WARNING "Value of CMAKE_SIZEOF_VOID_P (${CMAKE_SIZEOF_VOID_P}) is not supported.")
+  endif()
+else()
+  message(WARNING "Value of CMAKE_SYSTEM_PROCESSOR (${CMAKE_SYSTEM_PROCESSOR}) is unknown and cannot be used to set ABSL_RANDOM_RANDEN_COPTS")
+  set(ABSL_RANDOM_RANDEN_COPTS "")
+endif()
+
+
 if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
   set(ABSL_DEFAULT_COPTS "${ABSL_GCC_FLAGS}")
   set(ABSL_TEST_COPTS "${ABSL_GCC_FLAGS};${ABSL_GCC_TEST_FLAGS}")
-  set(ABSL_RANDOM_RANDEN_COPTS "${ABSL_RANDOM_HWAES_X64_FLAGS}")
 elseif("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang")
   # MATCHES so we get both Clang and AppleClang
   if(MSVC)
@@ -16,11 +35,9 @@ elseif("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang")
     set(ABSL_DEFAULT_COPTS "${ABSL_CLANG_CL_FLAGS}")
     set(ABSL_TEST_COPTS "${ABSL_CLANG_CL_FLAGS};${ABSL_CLANG_CL_TEST_FLAGS}")
     set(ABSL_DEFAULT_LINKOPTS "${ABSL_MSVC_LINKOPTS}")
-    set(ABSL_RANDOM_RANDEN_COPTS "${ABSL_RANDOM_HWAES_MSVC_X64_FLAGS}")
   else()
     set(ABSL_DEFAULT_COPTS "${ABSL_LLVM_FLAGS}")
     set(ABSL_TEST_COPTS "${ABSL_LLVM_FLAGS};${ABSL_LLVM_TEST_FLAGS}")
-    set(ABSL_RANDOM_RANDEN_COPTS "${ABSL_RANDOM_HWAES_X64_FLAGS}")
     if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
       # AppleClang doesn't have lsan
       # https://developer.apple.com/documentation/code_diagnostics
@@ -34,12 +51,10 @@ elseif("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC")
   set(ABSL_DEFAULT_COPTS "${ABSL_MSVC_FLAGS}")
   set(ABSL_TEST_COPTS "${ABSL_MSVC_FLAGS};${ABSL_MSVC_TEST_FLAGS}")
   set(ABSL_DEFAULT_LINKOPTS "${ABSL_MSVC_LINKOPTS}")
-  set(ABSL_RANDOM_RANDEN_COPTS "${ABSL_RANDOM_HWAES_MSVC_X64_FLAGS}")
 else()
   message(WARNING "Unknown compiler: ${CMAKE_CXX_COMPILER}.  Building with no default flags")
   set(ABSL_DEFAULT_COPTS "")
   set(ABSL_TEST_COPTS "")
-  set(ABSL_RANDOM_RANDEN_COPTS "")
 endif()
 
 if("${CMAKE_CXX_STANDARD}" EQUAL 98)