gh-149353: Avoid stale JIT stamp triggering rebuilds

[diegorusso]

• Issue: JIT shim build changes in #148872 can cause build steps to be unnecessarily repeated and with possible build breakage #149353

[diegorusso]

@ned-deily can you try this please?

[read-the-docs-community]

Documentation build overview

📚 cpython-previews | 🛠️ Build #32534730 | 📁 Comparing 3883cef against main (8c79678)

  🔍 Preview build  

3 files changed

± library/argparse.html
± whatsnew/3.15.html
± whatsnew/changelog.html

[ned-deily]

@ned-deily can you try this please?

@diegorusso Sorry, at least on macOS I don't see any difference: the make install step still starts by rebuilding jit.o.

[ned-deily]

Ah, I should have tried this before.

gmake --debug=w install
Makefile:979: update target 'check-clean-src' due to: target is .PHONY
Makefile:3395: update target 'Python/jit.o' due to: jit_stencils-aarch64-apple-darwin.h
gcc -c -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer  -fno-strict-overflow -Wsign-compare -Wunreachable-code -DNDEBUG -g -O3 -Wall    -std=c11 -Wextra -Wno-unused-parameter -Wno-missing-field-initializers -Wstrict-prototypes -Werror=implicit-function-declaration -fvisibility=hidden -Werror=unguarded-availability -D_Py_TIER2=3 -D_Py_JIT  -I./Include/internal -I./Include/internal/mimalloc  -I. -I./Include    -DPy_BUILD_CORE -o Python/jit.o Python/jit.c
Makefile:2115: update target 'Modules/getbuildinfo.o' due to: Python/jit.o
gcc -c -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer  -fno-strict-overflow -Wsign-compare -Wunreachable-code -DNDEBUG -g -O3 -Wall    -std=c11 -Wextra -Wno-unused-parameter -Wno-missing-field-initializers -Wstrict-prototypes -Werror=implicit-function-declaration -fvisibility=hidden -Werror=unguarded-availability -D_Py_TIER2=3 -D_Py_JIT  -I./Include/internal -I./Include/internal/mimalloc  -I. -I./Include    -DPy_BUILD_CORE \
      -DGITVERSION="\"`LC_ALL=C git --git-dir ./.git rev-parse --short HEAD`\"" \
      -DGITTAG="\"`LC_ALL=C git --git-dir ./.git describe --all --always --dirty`\"" \
      -DGITBRANCH="\"`LC_ALL=C git --git-dir ./.git name-rev --name-only HEAD`\"" \
      -o Modules/getbuildinfo.o ./Modules/getbuildinfo.c
Makefile:1953: update target 'Programs/_freeze_module' due to: Modules/getbuildinfo.o Python/jit.o
[...]

[ned-deily]

And, following the first make but before the make install:

-rw-r-----   1 nad staff      904 May  4 20:01 jit_shim-aarch64-apple-darwin.o
-rw-r-----   1 nad staff      253 May  4 20:01 jit_unwind_info-aarch64-apple-darwin.h
-rw-r-----   1 nad staff  2046781 May  4 20:02 jit_stencils-aarch64-apple-darwin.h
-rw-r-----  1 nad  staff  1356520 May  4 20:01 Python/jit.o

So it does think that jit.o is out-of-date.