Export of internal Abseil changes

--
ef2bf829c333f378ecc12f3259e3187cdb75a3d5 by Abseil Team <absl-team@google.com>:

debugging: fix the VDSO symbol name used for unwinding on RISC-V Linux

The name listed in `man vdso` is incorrect. Instead, use the name from `linux-5.16/arch/riscv/kernel/vdso/rt_sigreturn.S`

PiperOrigin-RevId: 439654174
Change-Id: Ib39d066f416681720068e806e828a2c76a14a532

--
43dfad824afd36cfc3e5049b4fea71a2bccb066c by Benjamin Barenblat <bbaren@google.com>:

Check printf format strings in str_format_convert_test

Add ABSL_PRINTF_ATTRIBUTE to appropriate functions in
strings/internal/str_format/convert_test. Correct
TypedFormatConvertTest.Char, which was accidentally passing values of
types larger than int to StrPrint.

PiperOrigin-RevId: 439388148
Change-Id: I6cde4e8e0c6455064138192430f07f4c990be0bc

--
f84b4ab2c3b070c8af0c82742ac7a8a4bf443bca by Derek Mauro <dmauro@google.com>:

Use __builtin_memcmp in the absl::string_view implementation
starting with MSVC 16.9, where it first appeared

This enables more constexpr operations

PiperOrigin-RevId: 439317316
Change-Id: Iaf1ce76b60901d4b2d5b96be5900c56572f57b15
GitOrigin-RevId: ef2bf829c333f378ecc12f3259e3187cdb75a3d5

5 files changed, 30 insertions, 13 deletions

diff --git a/absl/debugging/internal/stacktrace_riscv-inl.inc b/absl/debugging/internal/stacktrace_riscv-inl.inc
index b4bdb5f1..98b09a22 100644
--- a/absl/debugging/internal/stacktrace_riscv-inl.inc
+++ b/absl/debugging/internal/stacktrace_riscv-inl.inc
@@ -56,7 +56,7 @@ static const unsigned char *GetKernelRtSigreturnAddress() {
     absl::debugging_internal::VDSOSupport::SymbolInfo symbol_info;
     // Symbol versioning pulled from arch/riscv/kernel/vdso/vdso.lds at v5.10.
     auto lookup = [&](int type) {
-      return vdso.LookupSymbol("__kernel_rt_sigreturn", "LINUX_4.15", type,
+      return vdso.LookupSymbol("__vdso_rt_sigreturn", "LINUX_4.15", type,
                                &symbol_info);
     };
     if ((!lookup(STT_FUNC) && !lookup(STT_NOTYPE)) ||
diff --git a/absl/strings/BUILD.bazel b/absl/strings/BUILD.bazel
index 813aef45..1cf58ca1 100644
--- a/absl/strings/BUILD.bazel
+++ b/absl/strings/BUILD.bazel
@@ -1191,6 +1191,7 @@ cc_test(
     deps = [
         ":str_format_internal",
         ":strings",
+        "//absl/base:core_headers",
         "//absl/base:raw_logging_internal",
         "//absl/types:optional",
         "@com_google_googletest//:gtest_main",
diff --git a/absl/strings/CMakeLists.txt b/absl/strings/CMakeLists.txt
index d8715ed1..c4358a12 100644
--- a/absl/strings/CMakeLists.txt
+++ b/absl/strings/CMakeLists.txt
@@ -494,6 +494,7 @@ absl_cc_test(
   DEPS
     absl::strings
     absl::str_format_internal
+    absl::core_headers
     absl::raw_logging_internal
     absl::int128
     GTest::gmock_main
diff --git a/absl/strings/internal/str_format/convert_test.cc b/absl/strings/internal/str_format/convert_test.cc
index d9fbf61c..300612b7 100644
--- a/absl/strings/internal/str_format/convert_test.cc
+++ b/absl/strings/internal/str_format/convert_test.cc
@@ -24,6 +24,7 @@
 
 #include "gmock/gmock.h"
 #include "gtest/gtest.h"
+#include "absl/base/attributes.h"
 #include "absl/base/internal/raw_logging.h"
 #include "absl/strings/internal/str_format/bind.h"
 #include "absl/strings/match.h"
@@ -124,6 +125,7 @@ void StrAppendV(std::string *dst, const char *format, va_list ap) {
   delete[] buf;
 }
 
+void StrAppend(std::string *, const char *, ...) ABSL_PRINTF_ATTRIBUTE(2, 3);
 void StrAppend(std::string *out, const char *format, ...) {
   va_list ap;
   va_start(ap, format);
@@ -131,6 +133,7 @@ void StrAppend(std::string *out, const char *format, ...) {
   va_end(ap);
 }
 
+std::string StrPrint(const char *, ...) ABSL_PRINTF_ATTRIBUTE(1, 2);
 std::string StrPrint(const char *format, ...) {
   va_list ap;
   va_start(ap, format);
@@ -455,21 +458,32 @@ TYPED_TEST_P(TypedFormatConvertTest, AllIntsWithFlags) {
 }
 
 TYPED_TEST_P(TypedFormatConvertTest, Char) {
+  // Pass a bunch of values of type TypeParam to both FormatPack and libc's
+  // vsnprintf("%c", ...) (wrapped in StrPrint) to make sure we get the same
+  // value.
   typedef TypeParam T;
   using remove_volatile_t = typename std::remove_volatile<T>::type;
-  static const T kMin = std::numeric_limits<remove_volatile_t>::min();
-  static const T kMax = std::numeric_limits<remove_volatile_t>::max();
-  T kVals[] = {
-    remove_volatile_t(1), remove_volatile_t(2), remove_volatile_t(10),
-    remove_volatile_t(-1), remove_volatile_t(-2), remove_volatile_t(-10),
-    remove_volatile_t(0),
-    kMin + remove_volatile_t(1), kMin,
-    kMax - remove_volatile_t(1), kMax
+  std::vector<remove_volatile_t> vals = {
+      remove_volatile_t(1),  remove_volatile_t(2),  remove_volatile_t(10),   //
+      remove_volatile_t(-1), remove_volatile_t(-2), remove_volatile_t(-10),  //
+      remove_volatile_t(0),
   };
-  for (const T &c : kVals) {
+
+  // We'd like to test values near std::numeric_limits::min() and
+  // std::numeric_limits::max(), too, but vsnprintf("%c", ...) can't handle
+  // anything larger than an int. Add in the most extreme values we can without
+  // exceeding that range.
+  static const T kMin =
+      static_cast<remove_volatile_t>(std::numeric_limits<int>::min());
+  static const T kMax =
+      static_cast<remove_volatile_t>(std::numeric_limits<int>::max());
+  vals.insert(vals.end(), {kMin + 1, kMin, kMax - 1, kMax});
+
+  for (const T c : vals) {
     const FormatArgImpl args[] = {FormatArgImpl(c)};
     UntypedFormatSpecImpl format("%c");
-    EXPECT_EQ(StrPrint("%c", c), FormatPack(format, absl::MakeSpan(args)));
+    EXPECT_EQ(StrPrint("%c", static_cast<int>(c)),
+              FormatPack(format, absl::MakeSpan(args)));
   }
 }
 
diff --git a/absl/strings/string_view.h b/absl/strings/string_view.h
index a4c9a652..e3239f57 100644
--- a/absl/strings/string_view.h
+++ b/absl/strings/string_view.h
@@ -55,8 +55,9 @@ ABSL_NAMESPACE_END
 
 #else  // ABSL_USES_STD_STRING_VIEW
 
-#if ABSL_HAVE_BUILTIN(__builtin_memcmp) || \
-    (defined(__GNUC__) && !defined(__clang__))
+#if ABSL_HAVE_BUILTIN(__builtin_memcmp) ||        \
+    (defined(__GNUC__) && !defined(__clang__)) || \
+    (defined(_MSC_VER) && _MSC_VER >= 1928)
 #define ABSL_INTERNAL_STRING_VIEW_MEMCMP __builtin_memcmp
 #else  // ABSL_HAVE_BUILTIN(__builtin_memcmp)
 #define ABSL_INTERNAL_STRING_VIEW_MEMCMP memcmp