Export of internal Abseil changes.
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bb92c768e2271ddbebc1b1eb7e16a7b7c86a6e1c by Abseil Team <absl-team@google.com>:
Automated g4 rollback of changelist 244998488.
*** Reason for rollback ***
I'm seeing test failures, rolling this back.
*** Original change description ***
BEGIN_PUBLIC
The default constructor for optional<T> is filling dummy_ with zeros (see https://godbolt.org/z/IVea7X for a reduced example), which has a performance impact for large Ts. This comes from the gcc6 bugfix that made dummy as big as T. Because constexpr constructors are required to initialize all members of a struct, we cannot prevent this in a standard-compliant way as soon as dummy has any members (note that clang will happily accept adding a `constexpr dummy_type() {}` constructor...
***
PiperOrigin-RevId: 245004716
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6e3ee35af50ffbee604c22300f3260ebc5f6cf52 by Abseil Team <absl-team@google.com>:
The default constructor for optional<T> is filling dummy_ with zeros (see https://godbolt.org/z/IVea7X for a reduced example), which has a performance impact for large Ts. This comes from the gcc6 bugfix that made dummy as big as T. Because constexpr constructors are required to initialize all members of a struct, we cannot prevent this in a standard-compliant way as soon as dummy has any members (note that clang will happily accept adding a `constexpr dummy_type() {}` constructor to dummy_type to prevent zero-initialization, but this is UB AFAICT).
This all stems from the fact that we're constructing an object by using placement new on dummy_. The solution I'm using here is to do the placement new on the actual data_. This creates a new issue in when T is volatile, because we can no longer use `&data_` to do the placement new. The solution I'm using here is to make data_ a non-const and non-volatile T, and only provide fully possibly qualified access through `reference()` accessors. I think this correctly prevents UB.
PiperOrigin-RevId: 244998488
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4f52e64c4cf6aef8df6360007bcc53d8b00db2b4 by Abseil Team <absl-team@google.com>:
Increase SYMBOL_BUF_SIZE from 2KB to 3KB.
PiperOrigin-RevId: 244954529
GitOrigin-RevId: bb92c768e2271ddbebc1b1eb7e16a7b7c86a6e1c
Change-Id: Iaed9a027064a9ecd194c5c146169c683b77f12ef
diff --git a/absl/debugging/symbolize_elf.inc b/absl/debugging/symbolize_elf.inc
index 05fc297..5ac7ff5 100644
--- a/absl/debugging/symbolize_elf.inc
+++ b/absl/debugging/symbolize_elf.inc
@@ -305,7 +305,7 @@
char *tmp_buf, int tmp_buf_size);
enum {
- SYMBOL_BUF_SIZE = 2048,
+ SYMBOL_BUF_SIZE = 3072,
TMP_BUF_SIZE = 1024,
SYMBOL_CACHE_LINES = 128,
};
diff --git a/absl/hash/BUILD.bazel b/absl/hash/BUILD.bazel
index e1e6eae..8c2daf7 100644
--- a/absl/hash/BUILD.bazel
+++ b/absl/hash/BUILD.bazel
@@ -35,10 +35,10 @@
copts = ABSL_DEFAULT_COPTS,
linkopts = ABSL_DEFAULT_LINKOPTS,
deps = [
+ ":city",
"//absl/base:core_headers",
"//absl/base:endian",
"//absl/container:fixed_array",
- "//absl/hash:city",
"//absl/meta:type_traits",
"//absl/numeric:int128",
"//absl/strings",
