clang: Disable building dexp in clang-native

Building dexp (native) on Debian 11 causes intermittent failure[0].
This tools in not used in clang except in tests (that we don't run).

So, disable building this tool by encapsulating its build in a cmake
option and then in a PACKAGECONFIG.

Users sure of not using Debian 11 (or the impacted g++ compiler) can
turn this config on safely.

Only the -native* variants change. Dexp is still enabled by default for
target.

[0]: https://bugzilla.yoctoproject.org/show_bug.cgi?id=15803

Signed-off-by: Yoann Congal <yoann.congal@smile.fr>

3 files changed, 91 insertions, 0 deletions

diff --git a/recipes-devtools/clang/clang/0037-clangd-Add-a-build-option-to-disable-building-dexp.patch b/recipes-devtools/clang/clang/0037-clangd-Add-a-build-option-to-disable-building-dexp.patch
new file mode 100644
index 0000000..3851488
--- /dev/null
+++ b/recipes-devtools/clang/clang/0037-clangd-Add-a-build-option-to-disable-building-dexp.patch
@@ -0,0 +1,84 @@
+From 8001f900e602c0a8abcf118bda5869a2eb0d5ee9 Mon Sep 17 00:00:00 2001
+From: Yoann Congal <yoann.congal@smile.fr>
+Date: Tue, 25 Mar 2025 22:25:55 +0100
+Subject: [PATCH] clangd: Add a build option to disable building dexp
+
+Building dexp on Debian 11 currently causes intermittent failure[0][1].
+
+Adding the CLANGD_BUILD_DEXP option to disable dexp from the build
+allows Debian 11 users to build clang (albeit without the dexp tool).
+
+This option is set to "Build Dexp" by default so, no change is expected
+without manual setting.
+
+[0]: https://bugzilla.yoctoproject.org/show_bug.cgi?id=15803
+[1]: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1101322
+
+Upstream-Status: Submitted [https://github.com/llvm/llvm-project/pull/133124]
+Signed-off-by: Yoann Congal <yoann.congal@smile.fr>
+---
+ clang-tools-extra/clangd/CMakeLists.txt          | 8 +++++++-
+ clang-tools-extra/clangd/test/CMakeLists.txt     | 7 +++++--
+ clang-tools-extra/clangd/test/lit.site.cfg.py.in | 1 +
+ 3 files changed, 13 insertions(+), 3 deletions(-)
+
+diff --git a/clang-tools-extra/clangd/CMakeLists.txt b/clang-tools-extra/clangd/CMakeLists.txt
+index 6f10afe4a562..a1e9da41b4b3 100644
+--- a/clang-tools-extra/clangd/CMakeLists.txt
++++ b/clang-tools-extra/clangd/CMakeLists.txt
+@@ -210,6 +210,9 @@ if (CLANGD_ENABLE_REMOTE)
+   include(AddGRPC)
+ endif()
+ 
++option(CLANGD_BUILD_DEXP "Build the dexp tool as part of Clangd" ON)
++llvm_canonicalize_cmake_booleans(CLANGD_BUILD_DEXP)
++
+ if(CLANG_INCLUDE_TESTS)
+   add_subdirectory(test)
+   add_subdirectory(unittests)
+@@ -220,4 +223,7 @@ option(CLANGD_ENABLE_REMOTE "Use gRPC library to enable remote index support for
+ set(GRPC_INSTALL_PATH "" CACHE PATH "Path to gRPC library manual installation.")
+ 
+ add_subdirectory(index/remote)
+-add_subdirectory(index/dex/dexp)
++
++if(CLANGD_BUILD_DEXP)
++  add_subdirectory(index/dex/dexp)
++endif()
+diff --git a/clang-tools-extra/clangd/test/CMakeLists.txt b/clang-tools-extra/clangd/test/CMakeLists.txt
+index b51f461a4986..42fc3506641f 100644
+--- a/clang-tools-extra/clangd/test/CMakeLists.txt
++++ b/clang-tools-extra/clangd/test/CMakeLists.txt
+@@ -3,8 +3,6 @@ set(CLANGD_TEST_DEPS
+   ClangdTests
+   clangd-indexer
+   split-file
+-  # No tests for it, but we should still make sure they build.
+-  dexp
+   )
+ 
+ if(CLANGD_BUILD_XPC)
+@@ -12,6 +10,11 @@ if(CLANGD_BUILD_XPC)
+   list(APPEND CLANGD_TEST_DEPS ClangdXpcUnitTests)
+ endif()
+ 
++if(CLANGD_BUILD_DEXP)
++  # No tests for it, but we should still make sure they build.
++  list(APPEND CLANGD_TEST_DEPS dexp)
++endif()
++
+ if(CLANGD_ENABLE_REMOTE)
+   list(APPEND CLANGD_TEST_DEPS clangd-index-server clangd-index-server-monitor)
+ endif()
+diff --git a/clang-tools-extra/clangd/test/lit.site.cfg.py.in b/clang-tools-extra/clangd/test/lit.site.cfg.py.in
+index 1fe7c8d0f324..a0bb3561e19e 100644
+--- a/clang-tools-extra/clangd/test/lit.site.cfg.py.in
++++ b/clang-tools-extra/clangd/test/lit.site.cfg.py.in
+@@ -15,6 +15,7 @@ config.llvm_shlib_dir = "@SHLIBDIR@"
+ config.clangd_source_dir = "@CMAKE_CURRENT_SOURCE_DIR@/.."
+ config.clangd_binary_dir = "@CMAKE_CURRENT_BINARY_DIR@/.."
+ config.clangd_build_xpc = @CLANGD_BUILD_XPC@
++config.clangd_build_dexp = @CLANGD_BUILD_DEXP@
+ config.clangd_enable_remote = @CLANGD_ENABLE_REMOTE@
+ config.clangd_tidy_checks = @CLANGD_TIDY_CHECKS@
+ config.have_zlib = @LLVM_ENABLE_ZLIB@
diff --git a/recipes-devtools/clang/clang_git.bb b/recipes-devtools/clang/clang_git.bb
index 40e32c7..8fe5c6a 100644
--- a/recipes-devtools/clang/clang_git.bb
+++ b/recipes-devtools/clang/clang_git.bb
@@ -78,6 +78,12 @@ PACKAGECONFIG:class-nativesdk = "clangd \
 PACKAGECONFIG[bootstrap] = "-DCLANG_ENABLE_BOOTSTRAP=On -DCLANG_BOOTSTRAP_PASSTHROUGH='${PASSTHROUGH}' -DBOOTSTRAP_LLVM_ENABLE_LTO=Thin -DBOOTSTRAP_LLVM_ENABLE_LLD=ON,,,"
 PACKAGECONFIG[build-id] = "-DENABLE_LINKER_BUILD_ID=ON,-DENABLE_LINKER_BUILD_ID=OFF,,"
 PACKAGECONFIG[clangd] = "-DCLANG_ENABLE_CLANGD=ON,-DCLANG_ENABLE_CLANGD=OFF,,"
+
+# Activate to build the dexp tool in clangd
+# Disabled by default for -native since it is known to trigger compiler failure on Debian 11
+# See: https://bugzilla.yoctoproject.org/show_bug.cgi?id=15803
+PACKAGECONFIG[clangd-dexp] = "-DCLANGD_BUILD_DEXP=ON,-DCLANGD_BUILD_DEXP=OFF,,"
+
 PACKAGECONFIG[compiler-rt] = "-DCLANG_DEFAULT_RTLIB=compiler-rt,,"
 PACKAGECONFIG[eh] = "-DLLVM_ENABLE_EH=ON,-DLLVM_ENABLE_EH=OFF,,"
 PACKAGECONFIG[libcplusplus] = "-DCLANG_DEFAULT_CXX_STDLIB=libc++,,"
diff --git a/recipes-devtools/clang/common.inc b/recipes-devtools/clang/common.inc
index ef9e7eb..5f43192 100644
--- a/recipes-devtools/clang/common.inc
+++ b/recipes-devtools/clang/common.inc
@@ -55,6 +55,7 @@ SRC_URI = "\
     file://0034-scan-build-py-respect-LLVM_LIBDIR_SUFFIX-like-other-.patch \
     file://0035-compiler-rt-Do-not-pass-target-to-clang-compiler.patch \
     file://0036-Fix-build-on-ppc64-musl.patch \
+    file://0037-clangd-Add-a-build-option-to-disable-building-dexp.patch \
 "
 # Fallback to no-PIE if not set
 GCCPIE ??= ""