[Lldb-commits] [lldb] [LLDB] Remove fallthrough (PR #216398)

[Adrian Prantl via lldb-commits]

https://github.com/adrian-prantl created https://github.com/llvm/llvm-project/pull/216398

Address post-commit feedback on https://github.com/llvm/llvm-project/commit/8ad0f7cf78f12b51e91d3799593a1d766b6ab6a6.

>From 8ad0f7cf78f12b51e91d3799593a1d766b6ab6a6 Mon Sep 17 00:00:00 2001
From: Adrian Prantl <aprantl at apple.com>
Date: Fri, 14 Aug 2026 12:44:20 -0700
Subject: [PATCH 1/2] [lldb][CMake] Give the staged lldb-defines.h a build rule

a05b232076ed dropped lldb-defines.h from the header staging loop so
that the source header is never copied, leaving the staged copy to be
produced by a POST_BUILD command on liblldb-header-staging. Ninja
cannot see files produced that way, and LLDBRPCHeaders.cmake depends on
the staged path directly, so a clean build with LLDB_BUILD_LLDBRPC
enabled fails to even load the graph:

  ninja: error: 'include/lldb/lldb-defines.h', needed by
  'tools/lldb-rpc/DerivedHeaders/lldb-rpc-defines.h', missing and no
  known rule to make it

Dropping the header from the loop also removed it from
lldb_staged_headers and from LLDB.framework/Headers, even though
SBDefines.h includes it.

Stage the header through version-header-fix.py from inside the loop
instead. The script reads the source header and writes a fresh staged
copy, so the source tree can still be read-only, and the staged header
gets a rule that dependents can rely on.

Assisted-by: Claude
---
 lldb/source/API/CMakeLists.txt | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/lldb/source/API/CMakeLists.txt b/lldb/source/API/CMakeLists.txt
index 83ecb428d8ea4..c589756060a6b 100644
--- a/lldb/source/API/CMakeLists.txt
+++ b/lldb/source/API/CMakeLists.txt
@@ -284,8 +284,6 @@ set(generated_public_headers ${LLDB_OBJ_DIR}/include/lldb/API/SBLanguages.h)
 file(GLOB root_public_headers ${LLDB_SOURCE_DIR}/include/lldb/lldb-*.h)
 file(GLOB root_private_headers ${LLDB_SOURCE_DIR}/include/lldb/lldb-private*.h)
 list(REMOVE_ITEM root_public_headers ${root_private_headers})
-# Skip the initial copy of lldb-defines.h. The fixed version is generated at build time.
-list(REMOVE_ITEM root_public_headers ${LLDB_SOURCE_DIR}/include/lldb/lldb-defines.h)
 
 add_custom_command(
   OUTPUT ${lldb_header_staging_dir}
@@ -311,7 +309,12 @@ foreach(header
   get_filename_component(basename ${header} NAME)
   set(staged_header ${lldb_header_staging_dir}/${basename})
 
-  if(unifdef_EXECUTABLE)
+  if(basename STREQUAL "lldb-defines.h")
+    set(copy_command "${Python3_EXECUTABLE}"
+        ${LLDB_SOURCE_DIR}/scripts/version-header-fix.py
+        -i ${header} -o ${staged_header}
+        -m ${LLDB_VERSION_MAJOR} -n ${LLDB_VERSION_MINOR} -p ${LLDB_VERSION_PATCH})
+  elseif(unifdef_EXECUTABLE)
     # unifdef returns 0 when the file is unchanged and 1 if something was changed.
     # That means if we successfully remove SWIG code, the build system believes
     # that the command has failed and stops. This is undesirable.
@@ -345,9 +348,6 @@ foreach(header
   endif()
 endforeach()
 
-add_custom_command(TARGET liblldb-header-staging POST_BUILD
-  COMMAND "${Python3_EXECUTABLE}" ${LLDB_SOURCE_DIR}/scripts/version-header-fix.py -i ${LLDB_SOURCE_DIR}/include/lldb/lldb-defines.h -o ${lldb_header_staging_dir}/lldb-defines.h -m ${LLDB_VERSION_MAJOR} -n ${LLDB_VERSION_MINOR} -p ${LLDB_VERSION_PATCH}
-)
 add_dependencies(liblldb liblldb-header-staging)
 
 if(LLDB_BUILD_FRAMEWORK)

>From 9567979bb0e2953f9b5d8c92e4aeafb39fe25978 Mon Sep 17 00:00:00 2001
From: Adrian Prantl <aprantl at apple.com>
Date: Fri, 14 Aug 2026 13:45:25 -0700
Subject: [PATCH 2/2] [LLDB] Remove fallthrough

Address post-commit feedback on 8ad0f7cf78f12.
---
 lldb/source/API/CMakeLists.txt | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lldb/source/API/CMakeLists.txt b/lldb/source/API/CMakeLists.txt
index c589756060a6b..f7604b8f9cf73 100644
--- a/lldb/source/API/CMakeLists.txt
+++ b/lldb/source/API/CMakeLists.txt
@@ -314,7 +314,8 @@ foreach(header
         ${LLDB_SOURCE_DIR}/scripts/version-header-fix.py
         -i ${header} -o ${staged_header}
         -m ${LLDB_VERSION_MAJOR} -n ${LLDB_VERSION_MINOR} -p ${LLDB_VERSION_PATCH})
-  elseif(unifdef_EXECUTABLE)
+  endif()
+  if(unifdef_EXECUTABLE)
     # unifdef returns 0 when the file is unchanged and 1 if something was changed.
     # That means if we successfully remove SWIG code, the build system believes
     # that the command has failed and stops. This is undesirable.