src/test/run-make-fulldeps/coverage/coverage_tools.mk

   1 # Common Makefile include for Rust `run-make-fulldeps/instrument-coverage-* tests. Include this
   2 # file with the line:
   3 #
   4 # -include ../instrument-coverage/coverage_tools.mk
   5 #
   6 # To enable the Rust compiler option `-C link-dead-code`, also set the following variable
   7 # *BEFORE* the `-include` line:
   8 #
   9 # LINK_DEAD_CODE=yes
  10
  11 -include ../tools.mk
  12
  13 ifndef LINK_DEAD_CODE
  14         LINK_DEAD_CODE=no
  15 endif
  16
  17 # ISSUE(76038): When targeting MSVC, Rust binaries built with both `-Z instrument-coverage` and
  18 # `-C link-dead-code` typically crash (with a seg-fault) or at best generate an empty `*.profraw`
  19 # file, required for coverage reports.
  20 #
  21 # Enabling `-C link-dead-code` is preferred when compiling with `-Z instrument-coverage`, so
  22 # `-C link-dead-code` is automatically enabled for all platform targets _except_ MSVC.
  23 #
  24 # Making the state of `-C link-dead-code` platform-dependent creates a problem for cross-platform
  25 # tests because the injected counters, coverage reports, and some low-level output can be different,
  26 # depending on the `-C link-dead-code` setting. For example, coverage reports will not report any
  27 # coverage for a dead code region when the `-C link-dead-code` option is disabled, but with the
  28 # option enabled, those same regions will show coverage counter values (of zero, of course).
  29 #
  30 # To ensure cross-platform `-Z instrument-coverage` generate consistent output, the
  31 # `-C link-dead-code` option is always explicitly enabled or disabled.
  32 #
  33 # Since tests that execute binaries enabled with both `-Z instrument-coverage` and
  34 # `-C link-dead-code` are known to fail, those tests will need the `# ignore-msvc` setting.
  35 #
  36 # If and when the above issue is resolved, the `# ignore-msvc` option can be removed, and the
  37 # tests can be simplified to always test with `-C link-dead-code`.
  38
  39 UNAME = $(shell uname)
  40
  41 # FIXME(richkadel): Can any of the features tested by `run-make-fulldeps/coverage-*` tests be tested
  42 # just as completely by more focused unit tests of the code logic itself, to reduce the number of
  43 # test result files generated and maintained, and to help identify specific test failures and root
  44 # causes more easily?