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nix/src/libexpr/meson.build
Sergei Zimmerman 5e74c0e4d6
libexpr: Add SampleStack stack-sampling profiler
This patch adds support for a native stack sampling
profiler to the evaluator, which saves a collapsed stack
profile information to a configurable location.

Introduced options (in `EvalSettings`):

- `eval-profile-file` - path to the collected profile file.
- `eval-profiler-frequency` - sampling frequency.
- `eval-profiler` - enumeration option for enabling the profiler.

  Currently only `flamegraph` is supported, but having this an
  enumeration rather than a boolean switch leaves the door open
  for other profiler variants (e.g. tracy).

Profile includes the following information on best-effort basis (e.g. some lambdas might
have an undefined name). Callstack information contains:

- Call site location (where the function gets called).
- Primop/lambda name of the function being called.
- Functors/partial applications don't have a name attached to them unlike special-cased primops and lambads.

For cases where callsite location isn't available we have to resort to providing
the location where the lambda itself is defined. This removes some of the confusing
`«none»:0` locations in the profile from previous attempts.

Example usage with piping directly into zstd for compression:

```
nix eval --no-eval-cache nixpkgs#nixosTests.gnome \
  --eval-profiler flamegraph \
  --eval-profile-file >(zstd -of nix.profile.zstd)
```

Co-authored-by: Jörg Thalheim <joerg@thalheim.io>
2025-05-21 20:15:19 +00:00

187 lines
4.3 KiB
Meson

project('nix-expr', 'cpp',
version : files('.version'),
default_options : [
'cpp_std=c++2a',
# TODO(Qyriad): increase the warning level
'warning_level=1',
'errorlogs=true', # Please print logs for tests that fail
],
meson_version : '>= 1.1',
license : 'LGPL-2.1-or-later',
)
cxx = meson.get_compiler('cpp')
subdir('nix-meson-build-support/deps-lists')
configdata_pub = configuration_data()
configdata_priv = configuration_data()
deps_private_maybe_subproject = [
]
deps_public_maybe_subproject = [
dependency('nix-util'),
dependency('nix-store'),
dependency('nix-fetchers'),
]
subdir('nix-meson-build-support/subprojects')
subdir('nix-meson-build-support/big-objs')
# Check for each of these functions, and create a define like `#define HAVE_LCHOWN 1`.
check_funcs = [
'sysconf',
]
foreach funcspec : check_funcs
define_name = 'HAVE_' + funcspec.underscorify().to_upper()
define_value = cxx.has_function(funcspec).to_int()
configdata_priv.set(define_name, define_value)
endforeach
boost = dependency(
'boost',
modules : ['container', 'context'],
include_type: 'system',
)
# boost is a public dependency, but not a pkg-config dependency unfortunately, so we
# put in `deps_other`.
deps_other += boost
nlohmann_json = dependency('nlohmann_json', version : '>= 3.9')
deps_public += nlohmann_json
bdw_gc = dependency('bdw-gc', required : get_option('gc'))
if bdw_gc.found()
deps_public += bdw_gc
foreach funcspec : [
'pthread_attr_get_np',
'pthread_getattr_np',
]
define_name = 'HAVE_' + funcspec.underscorify().to_upper()
define_value = cxx.has_function(funcspec).to_int()
configdata_priv.set(define_name, define_value)
endforeach
# Affects ABI, because it changes what bdw_gc itself does!
configdata_pub.set('GC_THREADS', 1)
endif
# Used in public header. Affects ABI!
configdata_pub.set('NIX_USE_BOEHMGC', bdw_gc.found().to_int())
toml11 = dependency(
'toml11',
version : '>=3.7.0',
method : 'cmake',
include_type: 'system',
)
deps_other += toml11
config_priv_h = configure_file(
configuration : configdata_priv,
output : 'expr-config-private.hh',
)
subdir('nix-meson-build-support/common')
parser_tab = custom_target(
input : 'parser.y',
output : [
'parser-tab.cc',
'parser-tab.hh',
],
command : [
'bison',
'-v',
'-o',
'@OUTPUT0@',
'@INPUT@',
'-d',
],
# NOTE(Qyriad): Meson doesn't support installing only part of a custom target, so we add
# an install script below which removes parser-tab.cc.
install : true,
install_dir : get_option('includedir') / 'nix',
)
lexer_tab = custom_target(
input : [
'lexer.l',
parser_tab,
],
output : [
'lexer-tab.cc',
'lexer-tab.hh',
],
command : [
'flex',
'-Cf', # Use full scanner tables
'--outfile',
'@OUTPUT0@',
'--header-file=' + '@OUTPUT1@',
'@INPUT0@',
],
# NOTE(Qyriad): Meson doesn't support installing only part of a custom target, so we add
# an install script below which removes lexer-tab.cc.
install : true,
install_dir : get_option('includedir') / 'nix',
)
subdir('nix-meson-build-support/generate-header')
generated_headers = []
foreach header : [
'imported-drv-to-derivation.nix',
'fetchurl.nix',
]
generated_headers += gen_header.process(header)
endforeach
sources = files(
'attr-path.cc',
'attr-set.cc',
'eval-cache.cc',
'eval-error.cc',
'eval-gc.cc',
'eval-profiler-settings.cc',
'eval-profiler.cc',
'eval-settings.cc',
'eval.cc',
'function-trace.cc',
'get-drvs.cc',
'json-to-value.cc',
'lexer-helpers.cc',
'nixexpr.cc',
'paths.cc',
'primops.cc',
'print-ambiguous.cc',
'print.cc',
'search-path.cc',
'value-to-json.cc',
'value-to-xml.cc',
'value/context.cc',
)
subdir('include/nix/expr')
subdir('primops')
subdir('nix-meson-build-support/export-all-symbols')
subdir('nix-meson-build-support/windows-version')
this_library = library(
'nixexpr',
sources,
config_priv_h,
parser_tab,
lexer_tab,
generated_headers,
dependencies : deps_public + deps_private + deps_other,
include_directories : include_dirs,
link_args: linker_export_flags,
prelink : true, # For C++ static initializers
install : true,
)
install_headers(headers, subdir : 'nix/expr', preserve_path : true)
libraries_private = []
subdir('nix-meson-build-support/export')