llvm: don't touch VCS files
Builds of LLVM (& its subpackages) try to touch `.git/logs/HEAD` in
order to be able to cheaply determine when a header file that contains
VCS info should be updated.
As mentioned in the comment, users of this have to gracefully handle the
`touch` failing, but Portage's sandbox reports it as a violation and
fails the build regardless.
Just unconditionally skip touching the file so we avoid the sandbox
issues.
BUG=b:412322904
TEST=`emerge llvm` got to src_compile() instead of dying at
TEST=src_configure().
patch.cherry: false
patch.platforms: chromiumos
patch.version_range.from: 547379
patch.version_range.until: null
Change-Id: I021f090ae609127acb429031277906f9d74c9552
diff --git a/llvm/cmake/modules/AddLLVM.cmake b/llvm/cmake/modules/AddLLVM.cmake
index 99959ec..f015085 100644
--- a/llvm/cmake/modules/AddLLVM.cmake
+++ b/llvm/cmake/modules/AddLLVM.cmake
@@ -2542,14 +2542,13 @@
get_filename_component(git_dir ${git_output} ABSOLUTE BASE_DIR ${path})
# Some branchless cases (e.g. 'repo') may not yet have .git/logs/HEAD
if (NOT EXISTS "${git_dir}/logs/HEAD")
- execute_process(COMMAND ${CMAKE_COMMAND} -E touch HEAD
- WORKING_DIRECTORY "${git_dir}/logs"
- RESULT_VARIABLE touch_head_result
- ERROR_QUIET)
- if (NOT touch_head_result EQUAL 0)
- set(${out_var} "" PARENT_SCOPE)
- return()
- endif()
+ # ChromeOS-local: we often operate in the Portage sandbox, so patch out
+ # the creation of this file. Users of this function _must_ gracefully
+ # handle when it can't be written to, but Portage will still break the
+ # build after-the-fact because it observed an attempt to violate the
+ # sandbox. b/412322904
+ set(${out_var} "" PARENT_SCOPE)
+ return()
endif()
set(${out_var} "${git_dir}/logs/HEAD" PARENT_SCOPE)
endif()
