depends: hard-code necessary c(xx)flags rather than setting them per-host

fanquake commented at 9:33 am on May 22, 2025: member

The per-host flag values now represent the mandatory flags that cannot be overridden by the environment. Additionally, these flags (-pipe and -std=xx) will no longer be passed into the CMake build.

Pulled out of #31920.

DrahtBot commented at 9:33 am on May 22, 2025: contributor

The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.

Code Coverage & Benchmarks

For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/32584.

Reviews

See the guideline for information on the review process.

Type	Reviewers
ACK	ryanofsky
Concept ACK	hebasto

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fanquake added the label DrahtBot Guix build requested on May 22, 2025

hebasto commented at 10:28 am on May 22, 2025: member

Concept ACK.

maflcko commented at 12:08 pm on May 22, 2025: member

The per-host flag values now represent the mandatory flags that cannot be overridden by the environment. Additionally, these flags (-pipe and -std=xx) will no longer be passed into the CMake build.

Would be nice to explain this with commands to test and observe the difference in behavior. This would make it easier to understand the goals and test them.

hebasto commented at 2:21 pm on May 22, 2025: member

My Guix build:

 0aarch64
 17a5858e3364998675e06a2bec330a6fb9f619613a9228a568b5c98cba873460f  guix-build-0275825f7ace/output/aarch64-linux-gnu/SHA256SUMS.part
 2a8b08f5f246ca97ae26bf9142355797f82d3f1e7eb2ffbc1b7d78f35c4c0cd4d  guix-build-0275825f7ace/output/aarch64-linux-gnu/bitcoin-0275825f7ace-aarch64-linux-gnu-debug.tar.gz
 392cbdec0549173a3e3a90ac81ad2dac98d9758a76efe12a6d205cc1265f9f701  guix-build-0275825f7ace/output/aarch64-linux-gnu/bitcoin-0275825f7ace-aarch64-linux-gnu.tar.gz
 4c7915b68fdfa3fb68e78d6264f36ddca591204578d8f3d857c3d322a17522439  guix-build-0275825f7ace/output/arm-linux-gnueabihf/SHA256SUMS.part
 555777a80adf1abf9e39cac043e5736279b67b67dc8dac2a3c37a19cb37e71e54  guix-build-0275825f7ace/output/arm-linux-gnueabihf/bitcoin-0275825f7ace-arm-linux-gnueabihf-debug.tar.gz
 61ecff64fb689fdf879de55a5a702fdcf9e35617f012a40f989e1365304745ae3  guix-build-0275825f7ace/output/arm-linux-gnueabihf/bitcoin-0275825f7ace-arm-linux-gnueabihf.tar.gz
 7644d8e2e1b5cd4316703c6fa78d65a3ea575a31e1f24938efbf02eaadaf1bbc4  guix-build-0275825f7ace/output/arm64-apple-darwin/SHA256SUMS.part
 8e4fa5170eaf6b0dbc792f33bc163d8ba22b0a05c0bd1b1e225bc50ad48448720  guix-build-0275825f7ace/output/arm64-apple-darwin/bitcoin-0275825f7ace-arm64-apple-darwin-codesigning.tar.gz
 99684c05d427446218e72f40340f65680f8e2b1a06496b7ab3f65181daf432a9b  guix-build-0275825f7ace/output/arm64-apple-darwin/bitcoin-0275825f7ace-arm64-apple-darwin-unsigned.tar.gz
10a9b892fa30ef9e02c9066635bd7768a13c3971ec0035d13c0857a8c837af2170  guix-build-0275825f7ace/output/arm64-apple-darwin/bitcoin-0275825f7ace-arm64-apple-darwin-unsigned.zip
11b085ac19b1eac59497975bccbe4997b772a224c27c527376950590ce86b8ef82  guix-build-0275825f7ace/output/dist-archive/bitcoin-0275825f7ace.tar.gz
127da262d6ac77a64fc5c3a550c6b72dd9dd93a923cbf3045edc4696eb4e1af043  guix-build-0275825f7ace/output/powerpc64-linux-gnu/SHA256SUMS.part
135eef5b5c79b26f3f8ad3243637ca238b5e43f55f369375312ab186dc29213e7b  guix-build-0275825f7ace/output/powerpc64-linux-gnu/bitcoin-0275825f7ace-powerpc64-linux-gnu-debug.tar.gz
143a5f90e01e28fa920954bc551594936d359f0009033172d218cb31bd6842138b  guix-build-0275825f7ace/output/powerpc64-linux-gnu/bitcoin-0275825f7ace-powerpc64-linux-gnu.tar.gz
15ed6ce026a6ae7a22dfcdc7f9c8c2ab4df33f665562b65924633288fa9b19f7e8  guix-build-0275825f7ace/output/riscv64-linux-gnu/SHA256SUMS.part
16205569f39bc41d0b70206f08dbafae994afaedce32c2dd79972c9775dc916dd8  guix-build-0275825f7ace/output/riscv64-linux-gnu/bitcoin-0275825f7ace-riscv64-linux-gnu-debug.tar.gz
1790f23ce8f6498992b55069b5c8f616adfb9b5061bb301fee31f2e4ebc7912741  guix-build-0275825f7ace/output/riscv64-linux-gnu/bitcoin-0275825f7ace-riscv64-linux-gnu.tar.gz
184628de0d41b2a2fceddc115e66a54455cdd0eea61118c841ac9ba0dc789cf3c6  guix-build-0275825f7ace/output/x86_64-apple-darwin/SHA256SUMS.part
19e851467d91e4d0ccccd3a93e3b34a76eb1c7df22c5167014ee7273f9ea78b481  guix-build-0275825f7ace/output/x86_64-apple-darwin/bitcoin-0275825f7ace-x86_64-apple-darwin-codesigning.tar.gz
207e933ca4b5598f50d7c981f4c555965b383469c15a138c426c3151626de676b4  guix-build-0275825f7ace/output/x86_64-apple-darwin/bitcoin-0275825f7ace-x86_64-apple-darwin-unsigned.tar.gz
2103fe5fc86d56a1a88f5b50e2da2fad4c72449ae3f6922aa7366cd15e730f4b89  guix-build-0275825f7ace/output/x86_64-apple-darwin/bitcoin-0275825f7ace-x86_64-apple-darwin-unsigned.zip
2211de70c37658da525c7c24d9230ac56256c081446bd1db4adab6daa5bc4f44d6  guix-build-0275825f7ace/output/x86_64-linux-gnu/SHA256SUMS.part
23b9afb4e4991e07d33b221be4b3e8dbbafa97cd9ea32d86750d0badb507545ff0  guix-build-0275825f7ace/output/x86_64-linux-gnu/bitcoin-0275825f7ace-x86_64-linux-gnu-debug.tar.gz
24b52d43b67ff116532f7570ea370328f769058cb1b98e61bc4458ad9ea61816b6  guix-build-0275825f7ace/output/x86_64-linux-gnu/bitcoin-0275825f7ace-x86_64-linux-gnu.tar.gz
257a226edf53b81befd0f88897894dd379d5ff646d8e39e24d8d9cbadb349d2f71  guix-build-0275825f7ace/output/x86_64-w64-mingw32/SHA256SUMS.part
26eeb512d3fa02d381eb440b91eeb7c59498021181a6d59c7f4b6e2a7836e7b913  guix-build-0275825f7ace/output/x86_64-w64-mingw32/bitcoin-0275825f7ace-win64-codesigning.tar.gz
27f90557e9ec12797544e46ce487ea615c0034963e570e67ddace85fafdb654455  guix-build-0275825f7ace/output/x86_64-w64-mingw32/bitcoin-0275825f7ace-win64-debug.zip
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29ca9d189c66eb2b4f4f56f93272fd09ba2bf8d46dc68217782163020d2071c81e  guix-build-0275825f7ace/output/x86_64-w64-mingw32/bitcoin-0275825f7ace-win64-unsigned.zip

DrahtBot commented at 2:04 am on May 23, 2025: contributor

Guix builds (on x86_64) [untrusted test-only build, possibly unsafe, not for production use]

File	commit 35bf3f88398da0211cece0a29da4de001e34a4dd(master)	commit 21d855af47ee4cbcd038c588529566779181fc32(pull/32584/merge)
*-aarch64-linux-gnu-debug.tar.gz	`c35cf51a398c92df...`	`a22608e4225637a7...`
*-aarch64-linux-gnu.tar.gz	`82d0798dfae78051...`	`2f2705212ffa1c69...`
*-arm-linux-gnueabihf-debug.tar.gz	`df45940210e7d3b8...`	`34ac31537a9af3d6...`
*-arm-linux-gnueabihf.tar.gz	`f8999c6256936417...`	`68c1e4ec2a247131...`
*-arm64-apple-darwin-codesigning.tar.gz	`e33513a263389b7c...`	`81bf7cd522670770...`
*-arm64-apple-darwin-unsigned.tar.gz	`7c5a453513ec0850...`	`f47233df5c83e4cf...`
*-arm64-apple-darwin-unsigned.zip	`d57eb714e111132b...`	`e3dfe76fc44c05c2...`
*-powerpc64-linux-gnu-debug.tar.gz	`5467ae49d1d3c68c...`	`a7456d49c6dd2915...`
*-powerpc64-linux-gnu.tar.gz	`76f667e56592f732...`	`398f77f8f5877965...`
*-riscv64-linux-gnu-debug.tar.gz	`29c6f37babe24e24...`	`433a3a360708e910...`
*-riscv64-linux-gnu.tar.gz	`4ac255dfa3f295c6...`	`750d33b88fd4db35...`
*-x86_64-apple-darwin-codesigning.tar.gz	`1fab8a669d4b58c9...`	`1ca27635a9338e0e...`
*-x86_64-apple-darwin-unsigned.tar.gz	`abbbc7b484711bc7...`	`55a3db7ba7c8e60d...`
*-x86_64-apple-darwin-unsigned.zip	`d748d4548ea33f6c...`	`df58b83819fa4ba3...`
*-x86_64-linux-gnu-debug.tar.gz	`8fc1e04b90d920df...`	`0f1bab24f73b0f1f...`
*-x86_64-linux-gnu.tar.gz	`7831f9973e845882...`	`bcf9e56695d9437a...`
*.tar.gz	`eaf62bd30c82aab0...`	`2f988f8cbb8e698d...`
SHA256SUMS.part	`9ca1bc71bda735df...`	`f2b33615e84e95d3...`
guix_build.log	`810be13f8c3ecc43...`	`21055af7dd4549f6...`
guix_build.log.diff		`716ad18d12ece0ad...`

DrahtBot removed the label DrahtBot Guix build requested on May 23, 2025

DrahtBot added the label Build system on May 23, 2025

depends: hard-code necessary c(xx)flags rather than setting them per-host

The per-host flag values now represent the mandatory flags that cannot be
overridden by the environment. Additionally, these flags (-pipe and -std=xx)
will no longer be passed into the CMake build.

51f6aa8ac4

fanquake commented at 1:25 pm on May 30, 2025: member

Would be nice to explain this with commands to test and observe the difference in behavior. This would make it easier to understand the goals and test them.

Sure. On master (4b1d48a6866b24f0ed027334c6de642fc848d083):

0# flags in C(XX)FLAGS
1make -C depends print-linux_CFLAGS
2linux_CFLAGS=-pipe -std=c11
3make -C depends print-linux_CXXFLAGS
4linux_CXXFLAGS=-pipe -std=c++20

Libevent depends build:

0 make -C depends libevent
1# base cflags (-pipe -std=c11) present in libevent build
2-- CMAKE_C_FLAGS:            -I/root/ci_scratch/depends/x86_64-pc-linux-gnu/include -D_GNU_SOURCE -D_FORTIFY_SOURCE=3 -pipe -std=c11 -O2 -fdebug-prefix-map=/root/ci_scratch/depends/work/build/x86_64-pc-linux-gnu/libevent/2.1.12-stable-1afae5fc856=/usr -fmacro-prefix-map=/root/ci_scratch/depends/work/build/x86_64-pc-linux-gnu/libevent/2.1.12-stable-1afae5fc856=/usr -Wall -Wextra -Wno-unused-parameter -Wstrict-aliasing -Wstrict-prototypes -fno-strict-aliasing -Wmissing-prototypes -Winit-self -Wmissing-field-initializers -Wdeclaration-after-statement -Waddress -Wnormalized=id -Woverride-init -Wlogical-op -Wwrite-strings

CMake configure:

0# duplicated -std=c++20, -pipe
1C++ compiler flags .................... -m64 -pipe -std=c++20 -O2 -O2 -g -std=c++20 -fPIC -fno-extended-identifiers -fdebug-prefix-map=/root/ci_scratch/src=. -fmacro-prefix-map=/root/ci_scratch/src=. -fstack-reuse=none -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=3 -Wstack-protector -fstack-protector-all -fcf-protection=full -fstack-clash-protection -Wall -Wextra -Wformat -Wformat-security -Wvla -Wredundant-decls -Wdate-time -Wduplicated-branches -Wduplicated-cond -Wlogical-op -Woverloaded-virtual -Wsuggest-override -Wimplicit-fallthrough -Wunreachable-code -Wbidi-chars=any -Wundef -Wno-unused-parameter
2Linker flags .......................... -pipe -std=c++20 -O2 -O2 -g -fstack-reuse=none -fstack-protector-all -fcf-protection=full -fstack-clash-protection -Wl,-z,relro -Wl,-z,now -Wl,-z,separate-code -fPIE -pie

With this PR:

0# flags no-longer in C(XX)FLAGS
1make -C depends print-linux_CFLAGS
2linux_CFLAGS=
3make -C depends print-linux_CXXFLAGS
4linux_CXXFLAGS=

Libevent depends build:

0 make -C depends libevent
1# base cflags still present in libevent build
2-- CMAKE_C_FLAGS:            -I/root/ci_scratch/depends/x86_64-pc-linux-gnu/include -D_GNU_SOURCE -D_FORTIFY_SOURCE=3  -O2 -pipe -std=c11 -fdebug-prefix-map=/root/ci_scratch/depends/work/build/x86_64-pc-linux-gnu/libevent/2.1.12-stable-ce229553a77=/usr -fmacro-prefix-map=/root/ci_scratch/depends/work/build/x86_64-pc-linux-gnu/libevent/2.1.12-stable-ce229553a77=/usr -Wall -Wextra -Wno-unused-parameter -Wstrict-aliasing -Wstrict-prototypes -fno-strict-aliasing -Wmissing-prototypes -Winit-self -Wmissing-field-initializers -Wdeclaration-after-statement -Waddress -Wnormalized=id -Woverride-init -Wlogical-op -Wwrite-strings

CMake configure

0cmake -B build --toolchain /root/ci_scratch/depends/x86_64-pc-linux-gnu/toolchain.cmake
1# flags no-longer being passed through. 
2# No more duplicated -std=c++20, -pipe removed
3C++ compiler flags .................... -m64 -O2 -O2 -g -std=c++20 -fPIC -fno-extended-identifiers -fdebug-prefix-map=/root/ci_scratch/src=. -fmacro-prefix-map=/root/ci_scratch/src=. -fstack-reuse=none -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=3 -Wstack-protector -fstack-protector-all -fcf-protection=full -fstack-clash-protection -Wall -Wextra -Wformat -Wformat-security -Wvla -Wredundant-decls -Wdate-time -Wduplicated-branches -Wduplicated-cond -Wlogical-op -Woverloaded-virtual -Wsuggest-override -Wimplicit-fallthrough -Wunreachable-code -Wbidi-chars=any -Wundef -Wno-unused-parameter
4Linker flags .......................... -O2 -O2 -g -fstack-reuse=none -fstack-protector-all -fcf-protection=full -fstack-clash-protection -Wl,-z,relro -Wl,-z,now -Wl,-z,separate-code -fPIE -pie

fanquake force-pushed on May 30, 2025

fanquake commented at 3:47 pm on May 30, 2025: member

Guix Build:

 0c118e9965e3dc46a58e78ca4bb1573bf799d10b0a5a33c978ed5873801ded1e4  guix-build-51f6aa8ac47b/output/aarch64-linux-gnu/SHA256SUMS.part
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 3ec1a9597e32d60a8588b5ac75b5f37cde90275f0dc1eeaf5a68310b43a5a3c84  guix-build-51f6aa8ac47b/output/arm-linux-gnueabihf/SHA256SUMS.part
 490ae5ac3137e4644791f2e2c330df1c305552ba7346efec23fa5e343ac0500d2  guix-build-51f6aa8ac47b/output/arm-linux-gnueabihf/bitcoin-51f6aa8ac47b-arm-linux-gnueabihf-debug.tar.gz
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 6f0f35d08337a1cf6a2ec49d5c1ba763ef43e8bd742534f7ef2fb713e48241cd9  guix-build-51f6aa8ac47b/output/arm64-apple-darwin/SHA256SUMS.part
 75254245b0788ef0e14e263f4c95bb0495ea164350e5818d3cba8a3cb96716194  guix-build-51f6aa8ac47b/output/arm64-apple-darwin/bitcoin-51f6aa8ac47b-arm64-apple-darwin-codesigning.tar.gz
 84dc618aeccd57ea4cca4ba75b451e80ef2edcc198011c608042708ee7400472d  guix-build-51f6aa8ac47b/output/arm64-apple-darwin/bitcoin-51f6aa8ac47b-arm64-apple-darwin-unsigned.tar.gz
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123b685610b39a2e01665eed76e688871d8079533ebcfbbc0fe9b8f4fd69fe6114  guix-build-51f6aa8ac47b/output/powerpc64-linux-gnu/bitcoin-51f6aa8ac47b-powerpc64-linux-gnu-debug.tar.gz
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19645547eaaf9b37adbba3efca9387db9a50238dbc079853a0d40bd75565313e89  guix-build-51f6aa8ac47b/output/x86_64-apple-darwin/bitcoin-51f6aa8ac47b-x86_64-apple-darwin-unsigned.tar.gz
20b1ab6fd7a47c495bd5f18411f3d9ce4f2820e3f0ce2826fe40cdf8f05c42a99e  guix-build-51f6aa8ac47b/output/x86_64-apple-darwin/bitcoin-51f6aa8ac47b-x86_64-apple-darwin-unsigned.zip
215361f2e3f6c980579c663f9bebef8a60c5c939a8f70dacd8fc9d3a9dd6b94ba3  guix-build-51f6aa8ac47b/output/x86_64-linux-gnu/SHA256SUMS.part
2292f47e0af06207c53904f4ff4f3ff7dad2636e3d0c38bad5fb01ab434aca5d9b  guix-build-51f6aa8ac47b/output/x86_64-linux-gnu/bitcoin-51f6aa8ac47b-x86_64-linux-gnu-debug.tar.gz
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24f0c361e3efdbd799cbeb91e7423e9de5ee09f83a93c6857365b8ac1a4670a6ed  guix-build-51f6aa8ac47b/output/x86_64-w64-mingw32/SHA256SUMS.part
257d0341bf264916c96d8816f923affa37908d8b4a5ada3d4b276d2450ca874788  guix-build-51f6aa8ac47b/output/x86_64-w64-mingw32/bitcoin-51f6aa8ac47b-win64-codesigning.tar.gz
268d150336eb837673c964d3c9d2137ad9e475f1c6db457b7a845d3277b5a29d1b  guix-build-51f6aa8ac47b/output/x86_64-w64-mingw32/bitcoin-51f6aa8ac47b-win64-debug.zip
27f437f7403b6958d991d1f7d4d5f5b611cc2e3e245335b6bf5cf5b33aeff8a1cf  guix-build-51f6aa8ac47b/output/x86_64-w64-mingw32/bitcoin-51f6aa8ac47b-win64-setup-unsigned.exe
282b06924fe6e5f20a1a2993e63198584278be0407e312c392f6be0240d4a52f1d  guix-build-51f6aa8ac47b/output/x86_64-w64-mingw32/bitcoin-51f6aa8ac47b-win64-unsigned.zip

ryanofsky approved

ryanofsky commented at 4:14 pm on June 2, 2025: contributor

Code review ACK 51f6aa8ac47b7b5412553af2e7152d250a858d0d. This seems like a good change that deduplicates host definitions, and removes nonsensical inclusion of -std in host options rather than package options, since c/c++ standard versions should not vary by host.

IIUC, this change is mostly just a refactoring. For example, it rearranges the libevent flags shown by make print-libevent_cflags from:

0libevent_cflags=-pipe -std=c11 -O2 -fdebug-prefix-map=...

to:

0libevent_cflags= -O2 -pipe -std=c11 -fdebug-prefix-map=...

It also no longer adds -pipe and -std options to the cmake toolchain file used by the bitcoin build. But those options had effect anyway because they just duplicated cmake’s own flags.

This change does have a practical effect if flag environment variables are set. For example it changes CFLAGS=CUSTOM make print-libevent_cflags output from:

0libevent_cflags=CUSTOM  -fdebug-prefix-map=...

to

0libevent_cflags=CUSTOM  -pipe -std=c11 -fdebug-prefix-map=...

so setting custom flags no longer discards the -pipe -std=c11 options, which seems good for -std and maybe less good for -pipe, but probably fine.

I did find PR & commit description somewhat confusing. The first sentence “The per-host flag values now represent the mandatory flags that cannot be overridden by the environment” seems wrong because settting CFLAGS in the environment does override the host linux_CFLAGS value (this is easy to test with make print-libevent_cflags) due to the logic in:

https://github.com/bitcoin/bitcoin/blob/1c6602399be6de0148938a3fd7b51e6c48b985d2/depends/hosts/default.mk#L31-L37

Which only appends the linux_CFLAGS value to x86_64_linux_CFLAGS on line 35 if the CFLAGS value on line 31 is unset.

So maybe the sentence should say something like “The per-host flag variables hold platform-specific defaults that are ignored when flag environment variables are set, so it was wrong for them to contain -std options relied on by package definitions.”

It could be nice generally to make the PR description less abstract and try to describe the practical effects it has, and what it is intending to do.

DrahtBot requested review from hebasto on Jun 2, 2025

depends: hard-code necessary c(xx)flags rather than setting them per-host #32584

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