9847e205bf [docs] Improve commenting in ProcessGetData() (John Newbery)
2f032556e0 [test] test that an invalid GETDATA doesn't prevent processing of future messages (Amiti Uttarwar)
e257cf71c8 [net processing] ignore unknown INV types in GETDATA messages (Amiti Uttarwar)
047ceac142 [net processing] ignore tx GETDATA from blocks-only peers (Amiti Uttarwar)
Pull request description:
Currently we'll stall peers that send us an unknown INV type in a GETDATA message. Be a bit more friendly and just drop the invalid request.
Ditto for blocks-relay-only peers that send us a GETDATA for a transaction.
There's a test for the first part. The second is difficult to test in the functional test framework since we aren't able to make blocks-relay-only connections.
ACKs for top commit:
sipa:
utACK 9847e205bf
brakmic:
ACK 9847e205bf
luke-jr:
utACK 9847e205bf
naumenkogs:
utACK 9847e20
ajtowns:
utACK 9847e205bf
Tree-SHA512: 6007f2fd839ffe737727f6fb8e8f083b2d9e05a510748f1d40b8f9be8fdf7b5419a36d8f1039923eec1ba2983e8f6f0436ec5fc196d9f6dcb0657f2ff8ff8e4c
d044e0ec7d refactor: Remove override for final overriders (Hennadii Stepanov)
1551cea2d5 refactor: Use override for non-final overriders (Hennadii Stepanov)
Pull request description:
Two commits are split out from #16710 to make reviewing [easier](https://github.com/bitcoin/bitcoin/pull/16710#issuecomment-625760894).
From [C++ FAQ](https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines.html#c128-virtual-functions-should-specify-exactly-one-of-virtual-override-or-final):
> C.128: Virtual functions should specify exactly one of virtual, override, or final
> **Reason** Readability. Detection of mistakes. Writing explicit `virtual`, `override`, or `final` is self-documenting and enables the compiler to catch mismatch of types and/or names between base and derived classes. However, writing more than one of these three is both redundant and a potential source of errors.
ACKs for top commit:
practicalswift:
ACK d044e0ec7d: consistent use of `override` prevents bugs + patch looks correct + Travis happy
MarcoFalke:
ACK d044e0ec7d, based on my understanding that adding `override` or `final` to a function must always be correct, unless it doesn't compile!?
vasild:
ACK d044e0ec7
Tree-SHA512: 245fd9b99b8b5cbf8694061f892cb3435f3378c97ebed9f9401ce86d21890211f2234bcc39c9f0f79a4d2806cb31bf8ce41a0f9c2acef4f3a2ac5beca6b077cf
872aa25fa1 doc: add c++17-enable to fuzzing instructions (Martin Zumsande)
Pull request description:
Update the fuzzing doc because after the merge of #18901, C++17 is required for compilation.
ACKs for top commit:
practicalswift:
ACK 872aa25fa1
MarcoFalke:
ACK 872aa25fa1
Tree-SHA512: 47e37c033690de1d1fa644bf0cebb256036b32a5784021cc0d3b32e6188822d7f517d4342990dc7ec98de6d650794aeb85483157e69e141d6bd011993e124575
68537275bd build: Enable -Werror=sign-compare (Ben Woosley)
eac6a3080d refactor: Rework asmap Interpret to avoid ptrdiff_t (Ben Woosley)
df37377e30 test: Fix outstanding -Wsign-compare errors (Ben Woosley)
Pull request description:
Disallowing sign-comparison mismatches can help to prevent the introduction of overflow and interpretation bugs.
In this case, ~all~ most existing violations are in the tests, and most simply required annotating the literal as unsigned for comparison.
This was previously prevented by violations in leveldb which were fixed upstream and merged in #17398. You can test that by building this branch against: 22d11187ee vs 75fb37ce68
ACKs for top commit:
fjahr:
re-ACK 68537275bd
practicalswift:
ACK 68537275bd
Tree-SHA512: 14b5daa38c496fb51548feb30fb4dd179e6f76a8d355f52bc8e2a18f2f9340f0bc98dcf36d8b3d6521045d013891c3103749a4eda88ceef00202a6a0cf93f73c
420fa0770f fuzz: use std::optional for sep_pos variable (Harris)
Pull request description:
This PR changes the original `size_t sep_pos` to `std::optional<size_t> sep_post_opt` to remove the warning when compiling fuzz tests.
```shell
warning: variable 'sep_pos' may be uninitialized when used here [-Wconditional-uninitialized]
```
Also, it adds `--enable-c++17` flag to CI fuzz scripts.
ACKs for top commit:
practicalswift:
ACK 420fa0770f
MarcoFalke:
ACK 420fa07
Tree-SHA512: e967d5d8ab8ee7394b243ff5b28bac72d30bd14774e4a206f8c87474fad22769da76e4ba4e03cbef83b8f60e5293e9d9293b613e2e2e59e187d4e59ae6b874ca
095bc9a106 fuzz: fix vector size problem in system fuzzer (Harris)
Pull request description:
This PR fixes a problem with vector resizing in system fuzzer (*case 7* there). Originally, this problem was discussed in PR https://github.com/bitcoin/bitcoin/pull/18908
ACKs for top commit:
MarcoFalke:
ACK 095bc9a106
practicalswift:
ACK 095bc9a106
brakmic:
> ACK [095bc9a](095bc9a106)
Tree-SHA512: 73e6004ee51d68a34b49c79d1329a8c4865c21da888801c0fcc7f1bcacb510bf371bb61675eda83e53d08e0f24712e671369719523b0ced0eb2a22607bfa1d3d
d135c29476 [ci] make list of previous releases to download a setting (Sjors Provoost)
9c246b873c [test] backwards compatibility: bump v0.19.0.1 to v0.19.1 (Sjors Provoost)
89a28e02fa [test] add v0.16.3 backwards compatibility test (Sjors Provoost)
Pull request description:
Thanks to #18774's `adjust_bitcoin_conf_for_pre_17` we can now test backwards compatibility for v0.16.3, both for sync and loading a recent wallet.
This PR bumps v0.19.0.1 to v0.19.1.
I also made the version list consistent for the `contrib/devtools/previous_release.sh` instruction, between both tests.
ACKs for top commit:
MarcoFalke:
ACK d135c29476
Tree-SHA512: 5ff137a7a934237fa220f1c2807ce9abeeb75929266558bf3e4045bec7dfcd0a8747fa74d700065c568330b18badf58c60c308eb13d1eed444d4bbfe6decc48b
1e94a2bcbc depends: Add --sysroot option to mac os native compile flags (Russell Yanofsky)
Pull request description:
Catalina SDK clang stopped automatically searching the SDK include paths when invoked without `--sysroot`:
- https://github.com/bitcoin/bitcoin/pull/16367#issuecomment-594600985
- https://github.com/Homebrew/homebrew-core/issues/45061
This hasn't been a problem for current native depends packages because are passing their own `--sysroot` values, and hasn't been a problem for current host packages because they use `darwin_` commands instead of `build_darwin_` commands. But the current `build_darwin_CC` and `build_darwin_CXX` commands are still unnecessarily fragile, and incompatible with new native depends packages added in https://github.com/bitcoin/bitcoin/pull/18677.
Cory Fields (theuni) suggested in https://github.com/bitcoin/bitcoin/pull/16367#issuecomment-595393546 switching compiler from SDK clang to native clang (from $PATH) to avoid this problem. This is easy and makes a certain amount of sense for building native packages, as opposed to host packages. But Michael (fanquake) pointed out in https://github.com/bitcoin/bitcoin/pull/18677#discussion_r409934309 that it would be inconsistent to switch to non-SDK compilers while still using other SDK tools like `ranlib` and `install_name_tool`. So simplest, minimal fix seems to be just adding the missing `--sysroot` option.
ACKs for top commit:
ryanofsky:
> ACK [1e94a2b](1e94a2bcbc) - I think this change is ok, and I prefer it to the previous patch.
fanquake:
ACK 1e94a2bcbc - I think this change is ok, and I prefer it to the previous patch. Thanks for the summary in the PR description. I played around with Xcode and the CLT; I think previously I didn't fully grok the slight differences between the two.
Tree-SHA512: 4d4bbb7f49acb76d934a872a15b4e14f36290b508cb9e728815f959767ec174bcfb6d2ca7dcd995cc550d86980d64d4247ea5ecfca2301f0953006e50744fdb4
fa082d0a57 travis: Remove valgrind (MarcoFalke)
Pull request description:
When the valgrind run was added, it took 2 hours. Travis kindly raised the timeout limit to the maximum possible of 3 hours.
Today, a full build of Bitcoin Core with all tests takes more than three hours. Thus, it is impossible to run all tests on travis.
Moreover, the feedback loop for developers that create a pull request takes at least 2 hours, but in some cases (when the travis queue is full) until the next day. This is unacceptable.
Fix both issues by removing the build from travis.
Please note that the `ci/test/` configurations are *not* removed. They will stay in the repo and can be executed anywhere (just not on travis).
ACKs for top commit:
jamesob:
ACK fa082d0a57
jnewbery:
utACK fa082d0a57
Tree-SHA512: 9acaa0e2d3926014fadb7dd2e86c4e01df382e9399f6ae99f989fa609da66a77bdd1b75d6ff42d2686f38f730b8564e6dc722aa597a473290c9d30c2abe7ef0f
a029805f57 build: remove -Qunused-arguments workaround for clang + ccache (fanquake)
Pull request description:
This was added in 386efb7695 to address spammy Clang warnings when building with ccache.
The issue was addressed in [ccache 3.2](https://bugzilla.samba.org/show_bug.cgi?id=8118), and from a look at most major distros, it's only Debian Jessie that has a version of ccache older than that ([3.1](https://packages.debian.org/jessie/ccache)).
Therefore I think it's acceptable to drop this workaround, and re-enable warnings for unused driver arguments (when compiling using Clang and ccache).
ACKs for top commit:
hebasto:
ACK a029805f57.
vasild:
utACK a029805f57
Tree-SHA512: f887b9bd12f9c1c8d209943b86e8dafe33cfd1572912f2cafabe08ffe403973e48f0f7289280a8c6db9263c57aad43fbd4bb72f42db762eb090f3b1ef0538f43
03da4c7781 build: make linker checks more robust (Cory Fields)
Pull request description:
Check for a flag to turn linker warnings into errors. When flags are passed to
linkers via the compiler driver using a -Wl,-foo flag, linker warnings may be
swallowed rather than bubbling up.
This is one of [Corys commits](b9acd3d33e) that I've modified to also add `-Wl,-fatal_warnings`
for darwin.
ACKs for top commit:
vasild:
re-ACK 03da4c778
Tree-SHA512: 212031d619ed88e52aaae30cf3b711681d72c4d670884406403605d1d86c784c84cb07e2e0d6c30926e659db8f14f8dabd5af3de5291637f8080d6dfee358248
748977690e Add asmap_direct fuzzer that tests Interpreter directly (Pieter Wuille)
7cf97fda15 Make asmap Interpreter errors fatal and fuzz test it (Pieter Wuille)
c81aefc537 Add additional effiency checks to sanity checker (Pieter Wuille)
fffd8dca2d Add asmap sanity checker (Pieter Wuille)
5feefbe6e7 Improve asmap Interpret checks and document failures (Pieter Wuille)
2b3dbfa5a6 Deal with decoding failures explicitly in asmap Interpret (Pieter Wuille)
1479007a33 Introduce Instruction enum in asmap (Pieter Wuille)
Pull request description:
This improves/documents the failure cases inside the asmap interpreter. None of the changes are bug fixes (they only change behavior for corrupted asmap files), but they may make things easier to follow.
In a second step, a sanity checker is added that effectively executes every potential code path through the asmap file, checking the same failure cases as the interpreter, and more. It takes around 30 ms to run for me for a 1.2 MB asmap file.
I've verified that this accepts asmap files constructed by https://github.com/sipa/asmap/blob/master/buildmap.py with a large dataset, and no longer accepts it with 1 bit changed in it.
ACKs for top commit:
practicalswift:
ACK 748977690e modulo feedback below.
jonatack:
ACK 748977690e code review, regular build/tests/ran bitcoin with -asmap, fuzz build/ran both fuzzers overnight.
fjahr:
ACK 748977690e
Tree-SHA512: d876df3859735795c857c83e7155ba6851ce839bdfa10c18ce2698022cc493ce024b5578c1828e2a94bcdf2552c2f46c392a251ed086691b41959e62a6970821
fa47cf9d95 wallet: Fix typo in assert that is compile-time true (MarcoFalke)
Pull request description:
Commit 92bcd70808 presumably added a check that a `dest` of type `CNoDestination` implies an empty `scriptChange`.
However, it accidentally checked for `boost::variant::empty`, which always returns false: https://www.boost.org/doc/libs/1_72_0/doc/html/boost/variant.html#id-1_3_46_5_4_1_1_16_2-bb
ACKs for top commit:
Sjors:
utACK fa47cf9d95
Tree-SHA512: 9626b1e2947039853703932a362c2ee204e002d3344856eb93eef0e0f833401336f2dfa80fd43b83c8ec6eac624e6302aee771fb67aec436ba6483be02b8d615
71f183a49b build: warn on potentially uninitialized reads (Vasil Dimov)
Pull request description:
* Enable `conditional-uninitialized` warning class to show potentially uninitialized
reads.
* Fix the sole such warning in Bitcoin Core in `GetRdRand()`: `r1` would be
set to `0` on `rdrand` failure, so initializing it to `0` is a non-functional
change.
ACKs for top commit:
practicalswift:
ACK 71f183a49b
laanwj:
ACK 71f183a49b
Tree-SHA512: 2c1d8caacd86424b16a9d92e5df19e0bedb51ae111eecad7e3bfa46447bc88e5fff1f32dacf6c4a28257ebb3d87e79f80f074ce2c523ce08b1a0c0a67ab44204
fa09110ebb doc: Fix typo in Coin doxygen comment (MarcoFalke)
Pull request description:
`CTxOutCompressor` has been renamed in commit 4de934b9b5, so rename it in the docs as well.
ACKs for top commit:
laanwj:
ACK fa09110ebb
hebasto:
ACK fa09110ebb
Tree-SHA512: e16a21ac3112a67ee7d5ffabb3f47103aed8f91fdebf1bf96311cd0b7bdb9b7323ed826bfa95517386d4128ff0ae2c7c13bad047a7c5a0cc2458be7a43119157
Check for a flag to turn linker warnings into errors. When flags are passed to
linkers via the compiler driver using a -Wl,-foo flag, linker warnings may be
swallowed rather than bubbling up.
Co-authored-by: fanquake <fanquake@gmail.com>
1ad8ea2b73 net: remove is{Empty,Full} flags from CBloomFilter, clarify CVE fix (Sebastian Falbesoner)
Pull request description:
The BIP37 bloom filter class `CBloomFilter` contains two flags `isEmpty`/`isFull` together with an update method with the purpose to, according to the comments, "avoid wasting cpu", i.e. the mechanism should serve as an optimization for the trivial cases of empty (all bits zero) or full (all bits one) filters.
However, the real reason of adding those flags (introduced with commit 37c6389c5a by gmaxwell) was a _covert fix_ of [CVE-2013-5700](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-5700), a vulnerability that allowed a divide-by-zero remote node crash.
According to gmaxwell himself (https://github.com/bitcoin/bitcoin/pull/9060#issuecomment-257749165):
> the IsEmpty/IsFull optimizations were largely a pretextual optimization intended to make unexploitable a remote crash vulnerability (integer division by zero) that existed in the original bloom filtering code without disclosing it. I'm doubtful that they are all that useful. :)
For more information on how to trigger this crash, see PR https://github.com/bitcoin/bitcoin/pull/18515 which contains a detailled description and a regression test. It has also been discussed on a [recent PR club meeting on fuzzing](https://bitcoincore.reviews/18521.html).
The covert fix code already led to issues and PR based on the wrong assumption that the flags are there for optimization reasons (see #16886 and #16922). This PR gets rid of the flags and the update method and just focuses on the CVE fix itself, i.e. it can be seen as a revert of the covert fix commit modulo the actual fix.
ACKs for top commit:
meshcollider:
utACK 1ad8ea2b73
laanwj:
Concept and code review ACK 1ad8ea2b73
jkczyz:
ACK 1ad8ea2b73
MarcoFalke:
ACK 1ad8ea2b73
fjahr:
Code review ACK 1ad8ea2b73
Tree-SHA512: 29f7ff9faece0285e11e16c024851f5bcb772dec64118ccc3f9067ec256267ec8e1b1e3105c7de2a72fd122c3b085e8fc840ab8f4e49813f1cc7a444df1867f7
bfe1ba2f5b rel-builds: Specify core.abbrev for git-rev-parse (Carl Dong)
27e63e01cc build: Accomodate makensis v2.x (Carl Dong)
1f2c39a30e guix: Remove logical cores requirement (Carl Dong)
a4f6ffa71e lint: Also enable source statements for non-gitian (Carl Dong)
d256f91cb1 rel-builds: Directly deploy win installer to OUTDIR (Carl Dong)
fa791da02f nsis: Specify OutFile path only once (Carl Dong)
14701604d0 guix: Expose GIT_COMMON_DIR in container as readonly (Carl Dong)
f5a6ac4f48 guix: Make source tarball using git-archive (Carl Dong)
395c1137f6 gitian: Limit sourced script to just assignments (Carl Dong)
Pull request description:
Based on: #18556
Related: https://github.com/bitcoin/bitcoin/pull/17595#discussion_r399728721
ACKs for top commit:
fanquake:
ACK bfe1ba2f5b - I agree with Carl, and am going to merge this. I'd like for Linux Guix builds to be working again, and we can rebase #18818.
Tree-SHA512: c87ada7e3de17ca0b692a91029b86573442ded5780fc081c214773f6b374a0cdbeaf6f6898c36669c2e247ee32aa7f82defb1180f8decac52c65f0c140f18674
28b112e9bd Get rid of BindWallet (Russell Yanofsky)
d002f9d15d Disable CWalletTx copy constructor (Russell Yanofsky)
65b9d8f8dd Avoid copying CWalletTx in LoadToWallet (Russell Yanofsky)
bd2fbc7cdb Get rid of unneeded CWalletTx::Init parameter (Russell Yanofsky)
2b9cba2065 Remove CWalletTx merging logic from AddToWallet (Russell Yanofsky)
Pull request description:
This is a pure refactoring, no behavior is changing.
Instead of AddToWallet taking a temporary CWalletTx object and then potentially merging it with a pre-existing CWalletTx, have it take a callback so callers can update the pre-existing CWalletTx directly.
This makes AddToWallet simpler because now it is only has to be concerned with saving CWalletTx objects and not merging them.
This makes AddToWallet calls clearer because they can now make direct updates to CWalletTx entries without having to make temporary objects and then worry about how they will be merged.
Motivation for this change came from the bumpfee PR #8456 where we wanted to be able to call AddToWallet to make a simple update to an existing transaction, but were reluctant to, because the existing CWalletTx merging logic did not apply and seemed dangerous try to update as part of that PR. After this refactoring, the bumpfee PR could call AddToWallet safely instead of implementing a duplicate AddToWallet function.
This also allows getting rid of the CWalletTx copy constructor to prevent unintentional copying.
ACKs for top commit:
MarcoFalke:
Anyway, re-ACK 28b112e9bd
Tree-SHA512: 528dd088714472a237500b200f4433db850bdb7fc29c5e5d81cae48072061dfb967f7c37edd90b33f24901239f9be982988547c1f8c80abc25fb243fbf7330ef
fa13090d20 contrib: Remove optimize-pngs.py script, which lives in the maintainer repo (MarcoFalke)
Pull request description:
Moved to https://github.com/bitcoin-core/bitcoin-maintainer-tools/blob/master/optimize-pngs.py
Bitcoin Core should focus on the full node implementation, not on scripts to compress png images.
This script is only used when new PNG files are added to the repo. This happens about once every two years. So fetching the script from the other repo should not be a burden, but removing it from this repo is going to cut down on the meta files we need to maintain in the main repo.
ACKs for top commit:
practicalswift:
ACK fa13090d20 -- `+0 lines, -82 lines` :)
promag:
ACK fa13090d20.
hebasto:
ACK fa13090d20, verified that script is already [moved](https://github.com/bitcoin-core/bitcoin-maintainer-tools/pull/56).
Tree-SHA512: 37d111adae769bcddc6ae88041032d5a2b8b228fec67f555c8333c38de3992f5138b30bea868d7d6d6b7f966a47133e5853134373b149ab23cba3b8b560ecb31
2a78098098 wallet: Make sure no WalletDescriptor members are uninitialized after construction (practicalswift)
ff046aeeba wallet: Make sure no DescriptorScriptPubKeyMan members are uninitialized after construction (practicalswift)
Pull request description:
This is a small folllow-up to #16528 ("Native Descriptor Wallets using DescriptorScriptPubKeyMan") which was merged in to `master` a couple of hours ago.
Make sure no `DescriptorScriptPubKeyMan` or `WalletDescriptor` members are left uninitialized after construction.
Before this change `bool m_internal` was left uninitialized when using the `DescriptorScriptPubKeyMan(WalletStorage&, WalletDescriptor&)` ctor.
The same goes for the now initialized integers which were left uninitialized when using the `WalletDescriptor()` ctor.
ACKs for top commit:
instagibbs:
utACK 2a78098098
fjahr:
Code review ACK 2a78098098
Sjors:
utACK 2a78098
achow101:
ACK 2a78098098
brakmic:
Code review ACK 2a78098098
meshcollider:
utACK 2a78098098
Tree-SHA512: c98e035268fdc7f65a423b73ac0cf010b0ef7c5e679b3cf170c1813efac8ab5c657dcbaf43c746770bea59e4772bfefe4caa834f1175260c39c7f35d92946ba5
0ae8f18dfe build: add -Wgnu to compile flags (fanquake)
3a0fd7726b Remove use of non-standard zero variadic macros (Ben Woosley)
49f6178c3e Drop unused LOG_TIME_MICROS helper (Ben Woosley)
5d4999951e prevector: Avoid unnamed struct, which is a GNU extension (DesWurstes)
Pull request description:
Since we [started using](https://github.com/bitcoin/bitcoin/pull/7165) the `ax_cxx_compile_stdcxx.m4` macro we've been passing `[noext]` to indicate that we don't want to use an extended mode, i.e GNU extensions. Speaking to Cory he clarified that the intention was to "require only vanilla c++11 and turn _off_ extension support so they would fail to compile".
However in the codebase we are currently making use of some GNU extensions. We should either remove there usage, or at least amend our CXX compiler checks. I'd prefer the former.
#### anonymous structs
```bash
./prevector.h:153:9: warning: anonymous structs are a GNU extension [-Wgnu-anonymous-struct]
struct {
```
This is fixed in b849212c1e.
#### variadic macros
```bash
./undo.h:57:50: warning: must specify at least one argument for '...' parameter of variadic macro [-Wgnu-zero-variadic-macro-arguments]
::Unserialize(s, VARINT(nVersionDummy));
```
This is taken care of in #18087.
The `LOG_TIME_*` macros introduced in #16805 make use of a [GNU extension](https://gcc.gnu.org/onlinedocs/cpp/Variadic-Macros.html).
```bash
In file included from validation.cpp:22:
./logging/timer.h:99:99: warning: token pasting of ',' and __VA_ARGS__ is a GNU extension [-Wgnu-zero-variadic-macro-arguments]
BCLog::Timer<std::chrono::milliseconds> PASTE2(logging_timer, __COUNTER__)(__func__, end_msg, ## __VA_ARGS__)
^
./logging/timer.h:99:99: warning: token pasting of ',' and __VA_ARGS__ is a GNU extension [-Wgnu-zero-variadic-macro-arguments]
./logging/timer.h:99:99: warning: token pasting of ',' and __VA_ARGS__ is a GNU extension [-Wgnu-zero-variadic-macro-arguments]
./logging/timer.h:99:99: warning: token pasting of ',' and __VA_ARGS__ is a GNU extension [-Wgnu-zero-variadic-macro-arguments]
./logging/timer.h:99:99: warning: token pasting of ',' and __VA_ARGS__ is a GNU extension [-Wgnu-zero-variadic-macro-arguments]
./logging/timer.h:101:92: warning: token pasting of ',' and __VA_ARGS__ is a GNU extension [-Wgnu-zero-variadic-macro-arguments]
BCLog::Timer<std::chrono::seconds> PASTE2(logging_timer, __COUNTER__)(__func__, end_msg, ## __VA_ARGS__)
^
6 warnings generated.
```
This is fixed in 081a0ab64eb442bc85c4d4a4d3bc2c8e97ac2a6d and 612e8e138b97fc5ad2f38847300132a8fc423c3f.
#### prevention
To ensure that usage doesn't creep back in we can add [`-Wgnu`](https://clang.llvm.org/docs/DiagnosticsReference.html#wgnu) to our compile time flags, which will make Clang warn whenever it encounters GNU extensions.
This would close#14130.
Also related to #17230, where it's suggested we use a GNU extension, the `gnu::pure` attribute.
ACKs for top commit:
practicalswift:
ACK 0ae8f18dfe -- diff looks correct
MarcoFalke:
ACK 0ae8f18dfe
vasild:
utACK 0ae8f18df
dongcarl:
ACK 0ae8f18dfe
Tree-SHA512: c517404681ef8edf04c785731d26105bac9f3c9c958605aa24cbe399c649e7c5ee0c4aa8e714fd2b2d335e2fbea4d571e09b0dec36678ef871f0a6683ba6bb7f
