envoy: disable "-Werror" in protobuf

From 448e4e14f4f188687580362a861ae4a0dbb5b1fb Mon Sep 17 00:00:00 2001

From: "Krinkin, Mike" <krinkin.m.u@gmail.com>

Date: Sat, 16 Nov 2024 00:40:40 +0000

Subject: [PATCH] [contrib] Disable GCC warnings and broken features (#37131)

Currently contrib does not build with GCC because of various false

positive compiler warnings turned to errors and a GCC compiler bug.

Let's first start with the bug, in GCC apparently

using -gsplit-dwarf (debug fission) and -fdebug-types-section (used to

optimize the size of debug inforamtion), when used together, can result

in a linker failure.

Refer to https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110885 for the GCC

bug report of this issue. When it comes to Envoy, optimized builds with

GCC are affected on at least GCC 11 (used by --config=docker-gcc) and

GCC 12 (and I'm pretty sure the bug isn't fixed in any newer versions

either, though I didn't check each version).

Given that we cannot have both debug fission and a debug types section,

we decided to abandon the debug types sections and keep the fission.

That being said, apparently both of those options are unmaintained in

GCC which poses a question of long term viability of using those or GCC.

Other changes in this commit disable GCC compiler errors for various

warnings that happen when building contrib. I checked those warnings and

didn't find any true

positive.

And additionally, for warnings that exists in both Clang and GCC, Clang

warnings don't trigger, so Clang also disagrees with GCC here.

Additionally missing-requires warning is new and does not exist in GCC

11, but exists in later versions of GCC, so to avoid breaking on this

warning for future versions of GCC I disabled it, but also tell GCC to

not complain if it sees a flag related to an unknwon diagnostic.

This is the last change required to make GCC contrib builds work (you

can find more context and discussions in

https://github.com/envoyproxy/envoy/issues/31807)

Risk Level: Low

Testing: building with --config=gcc and --config=docker-gcc

Docs Changes: N/A

Release Notes: N/A

Platform Specific Features: N/A

Fixes #31807

Signed-off-by: Mikhail Krinkin <krinkin.m.u@gmail.com>

---

 .bazelrc                 | 18 +++++++++++++++++-

 bazel/envoy_internal.bzl | 16 +++++++++++++++-

 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/.bazelrc b/.bazelrc

index e0e4899cecf1..7df94c77944c 100644

--- a/.bazelrc

+++ b/.bazelrc

@@ -57,9 +57,9 @@ test --experimental_ui_max_stdouterr_bytes=11712829 #default 1048576

 # Allow tags to influence execution requirements

 common --experimental_allow_tags_propagation

+build:linux --copt=-fdebug-types-section

 # Enable position independent code (this is the default on macOS and Windows)

 # (Workaround for https://github.com/bazelbuild/rules_foreign_cc/issues/421)

-build:linux --copt=-fdebug-types-section

 build:linux --copt=-fPIC

 build:linux --copt=-Wno-deprecated-declarations

 build:linux --cxxopt=-std=c++20 --host_cxxopt=-std=c++20

@@ -95,6 +95,21 @@ build:gcc --linkopt=-fuse-ld=gold --host_linkopt=-fuse-ld=gold

 build:gcc --test_env=HEAPCHECK=

 build:gcc --action_env=BAZEL_COMPILER=gcc

 build:gcc --action_env=CC=gcc --action_env=CXX=g++

+# This is to work around a bug in GCC that makes debug-types-section

+# option not play well with fission:

+# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110885

+build:gcc --copt=-fno-debug-types-section

+# These trigger errors in multiple places both in Envoy dependecies

+# and in Envoy code itself when using GCC.

+# And in all cases the reports appear to be clear false positives.

+build:gcc --copt=-Wno-error=restrict

+build:gcc --copt=-Wno-error=uninitialized

+build:gcc --cxxopt=-Wno-missing-requires

+# We need this because -Wno-missing-requires options is rather new

+# in GCC, so flags -Wno-missing-requires exists in GCC 12, but does

+# not in GCC 11 and GCC 11 is what is used in docker-gcc

+# configuration currently

+build:gcc --cxxopt=-Wno-unknown-warning

 # Clang-tidy

 # TODO(phlax): enable this, its throwing some errors as well as finding more issues

@@ -375,6 +390,7 @@ build:docker-clang-libc++ --config=docker-sandbox

 build:docker-clang-libc++ --config=rbe-toolchain-clang-libc++

 build:docker-gcc --config=docker-sandbox

+build:docker-gcc --config=gcc

 build:docker-gcc --config=rbe-toolchain-gcc

 build:docker-asan --config=docker-sandbox

diff --git a/bazel/envoy_internal.bzl b/bazel/envoy_internal.bzl

index 015659851c1b..27ecaa0bbf47 100644

--- a/bazel/envoy_internal.bzl

+++ b/bazel/envoy_internal.bzl

@@ -68,7 +68,21 @@ def envoy_copts(repository, test = False):

                    "-Wc++2a-extensions",

                    "-Wrange-loop-analysis",

                ],

-               repository + "//bazel:gcc_build": ["-Wno-maybe-uninitialized"],

+               repository + "//bazel:gcc_build": [

+                   "-Wno-maybe-uninitialized",

+                   # GCC implementation of this warning is too noisy.

+                   #

+                   # It generates warnings even in cases where there is no ambiguity

+                   # between the overloaded version of a method and the hidden version

+                   # from the base class. E.g., when the two have different number of

+                   # arguments or incompatible types and therefore a wrong function

+                   # cannot be called by mistake without triggering a compiler error.

+                   #

+                   # As a safeguard, this warning is only disabled for GCC builds, so

+                   # if Clang catches a problem in the code we would get a warning

+                   # anyways.

+                   "-Wno-error=overloaded-virtual",

+               ],

                # Allow 'nodiscard' function results values to be discarded for test code only

                # TODO(envoyproxy/windows-dev): Replace /Zc:preprocessor with /experimental:preprocessor

                # for msvc versions between 15.8 through 16.4.x. see

diff -Naur a/bazel/protobuf.patch b/bazel/protobuf.patch

--- a/bazel/protobuf.patch	2025-01-06 23:00:26.683972526 +0100

+++ b/bazel/protobuf.patch	2025-01-07 00:53:33.997482569 +0100

@@ -149,3 +149,15 @@

  #if PROTOBUF_ENABLE_DEBUG_LOGGING_MAY_LEAK_PII

  #define PROTOBUF_DEBUG true

  #else

+diff -Naur a/build_defs/cpp_opts.bzl b/build_defs/cpp_opts.bzl

+--- a/build_defs/cpp_opts.bzl	2025-01-06 23:02:56.356552216 +0100

++++ b/build_defs/cpp_opts.bzl	2025-01-07 00:23:30.534047300 +0100

+@@ -22,7 +22,7 @@

+         "-Woverloaded-virtual",

+         "-Wno-sign-compare",

+         "-Wno-nonnull",

+-        "-Werror",

++        "-Wno-maybe-uninitialized",

+     ],

+ })

+ 

  # these need to be updated for any changes to fetchAttrs

  depsHash =

    {

      x86_64-linux = "sha256-KQ0ZxLC/ZLLcypmb1UlVXvLWErLmxuednjKRFaBgKuQ=";

      aarch64-linux = "sha256-DkibjmY1YND9Q2aQ41bhNdch0SKM5ghY2mjYSQfV30M=";

      x86_64-linux = "sha256-qny2l+gIoWCVRZIodd/Tzuj88f/+ajNXeZo/b9XEfVE=";

      aarch64-linux = "sha256-DkibjmY1YND9Q2aQ41bhNdch0SKM5ghY2mjYSQfV31N=";

    }

    .${stdenv.system} or (throw "unsupported system ${stdenv.system}");

      # cherry-pick of https://github.com/envoyproxy/envoy/commit/019f589da2cc8da7673edd077478a100b4d99436

      # drop with v1.33.x

      ./0005-deps-Bump-rules_rust-0.54.1-37056.patch

      # patch gcc flags to work with GCC 14

      # (silences erroneus -Werror=maybe-uninitialized and others)

      # cherry-pick of https://github.com/envoyproxy/envoy/commit/448e4e14f4f188687580362a861ae4a0dbb5b1fb

      # drop with v1.33.x

      ./0006-gcc-warnings.patch

      # Remove "-Werror" from protobuf build

      # This is fixed in protobuf v28 and later:

      # https://github.com/protocolbuffers/protobuf/commit/f5a1b178ad52c3e64da40caceaa4ca9e51045cb4

      # drop with v1.33.x

      ./0007-protobuf-remove-Werror.patch

    ];

    postPatch = ''

      chmod -R +w .

      "--noexperimental_strict_action_env"

      "--cxxopt=-Wno-error"

      "--linkopt=-Wl,-z,noexecstack"

      "--config=gcc"

      "--verbose_failures"

      # Force use of system Java.

      "--extra_toolchains=@local_jdk//:all"