[PATCH 0/2] MR7119: ntdll, loader: Add __attribute__((used)) to a few symbols that shouldn't be discarded.

[William Horvath (＠whrvth)]

These changes are enough to allow building the entirety of the native (ELF) side with `-flto`.

[PATCH 1/2] ntdll: Mark call_init_thunk "used".

[William Horvath]

From: William Horvath

It's only referenced by inline asm, so this prevents the linker
from discarding the symbol if (e.g.) LTO is used.
---
 dlls/ntdll/unix/signal_arm.c    | 2 +-
 dlls/ntdll/unix/signal_arm64.c  | 2 +-
 dlls/ntdll/unix/signal_i386.c   | 2 +-
 dlls/ntdll/unix/signal_x86_64.c | 2 +-
 4 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/dlls/ntdll/unix/signal_arm.c b/dlls/ntdll/unix/signal_arm.c
index c9ae492597d..f2c45e7b99e 100644
--- a/dlls/ntdll/unix/signal_arm.c
+++ b/dlls/ntdll/unix/signal_arm.c
@@ -1121,7 +1121,7 @@ void signal_init_process(void)
 /***********************************************************************
  *           call_init_thunk
  */
-void call_init_thunk( LPTHREAD_START_ROUTINE entry, void *arg, BOOL suspend, TEB *teb,
+void __attribute__((used)) call_init_thunk( LPTHREAD_START_ROUTINE entry, void *arg, BOOL suspend, TEB *teb,
                       struct syscall_frame *frame, void *syscall_cfa )
 {
     struct arm_thread_data *thread_data = (struct arm_thread_data *)&teb->GdiTebBatch;
diff --git a/dlls/ntdll/unix/signal_arm64.c b/dlls/ntdll/unix/signal_arm64.c
index 57d9c375076..4aead01ff9d 100644
--- a/dlls/ntdll/unix/signal_arm64.c
+++ b/dlls/ntdll/unix/signal_arm64.c
@@ -1447,7 +1447,7 @@ void syscall_dispatcher_return_slowpath(void)
 /***********************************************************************
  *           call_init_thunk
  */
-void call_init_thunk( LPTHREAD_START_ROUTINE entry, void *arg, BOOL suspend, TEB *teb,
+void __attribute__((used)) call_init_thunk( LPTHREAD_START_ROUTINE entry, void *arg, BOOL suspend, TEB *teb,
                       struct syscall_frame *frame, void *syscall_cfa )
 {
     struct arm64_thread_data *thread_data = (struct arm64_thread_data *)&teb->GdiTebBatch;
diff --git a/dlls/ntdll/unix/signal_i386.c b/dlls/ntdll/unix/signal_i386.c
index 8ae7afc769e..1a14886d000 100644
--- a/dlls/ntdll/unix/signal_i386.c
+++ b/dlls/ntdll/unix/signal_i386.c
@@ -2496,7 +2496,7 @@ void signal_init_process(void)
 /***********************************************************************
  *           call_init_thunk
  */
-void call_init_thunk( LPTHREAD_START_ROUTINE entry, void *arg, BOOL suspend, TEB *teb,
+void __attribute__((used)) call_init_thunk( LPTHREAD_START_ROUTINE entry, void *arg, BOOL suspend, TEB *teb,
                       struct syscall_frame *frame, void *syscall_cfa )
 {
     struct x86_thread_data *thread_data = (struct x86_thread_data *)&teb->GdiTebBatch;
diff --git a/dlls/ntdll/unix/signal_x86_64.c b/dlls/ntdll/unix/signal_x86_64.c
index caa85249896..799f29ab2a2 100644
--- a/dlls/ntdll/unix/signal_x86_64.c
+++ b/dlls/ntdll/unix/signal_x86_64.c
@@ -2575,7 +2575,7 @@ void signal_init_process(void)
 /***********************************************************************
  *           call_init_thunk
  */
-void call_init_thunk( LPTHREAD_START_ROUTINE entry, void *arg, BOOL suspend, TEB *teb,
+void __attribute__((used)) call_init_thunk( LPTHREAD_START_ROUTINE entry, void *arg, BOOL suspend, TEB *teb,
                       struct syscall_frame *frame, void *syscall_cfa )
 {
     struct amd64_thread_data *thread_data = (struct amd64_thread_data *)&teb->GdiTebBatch;

[PATCH 2/2] loader: Mark thread_ldt, thread_data, wld_start "used".

[William Horvath]

From: William Horvath

They're only referenced by inline asm, so this prevents the linker
from discarding the symbol if (e.g.) LTO is used.
---
 loader/preloader.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/loader/preloader.c b/loader/preloader.c
index d0551bae63a..3df0884d611 100644
--- a/loader/preloader.c
+++ b/loader/preloader.c
@@ -181,6 +181,7 @@ void __bb_init_func(void) { return; }

static int thread_data[256];

+__attribute__((used))
 struct
 {
     /* this is the kernel modify_ldt struct */
@@ -333,7 +334,7 @@ static inline int wld_prctl( int code, long arg )

#elif defined(__x86_64__)

-void *thread_data[256];
+void __attribute__((used)) *thread_data[256];

/*
  * The _start function is the entry and exit point of this program
@@ -422,7 +423,7 @@ SYSCALL_NOERR( wld_getegid, 108 /* SYS_getegid */ );

#elif defined(__aarch64__)

-void *thread_data[256];
+void __attribute__((used)) *thread_data[256];

/*
  * The _start function is the entry and exit point of this program
@@ -529,7 +530,7 @@ SYSCALL_NOERR( wld_getegid, 177 /* SYS_getegid */ );

#elif defined(__arm__)

-void *thread_data[256];
+void __attribute__((used)) *thread_data[256];

/*
  * The _start function is the entry and exit point of this program
@@ -1395,7 +1396,7 @@ static void set_process_name( int argc, char *argv[] )
  *  Load the binary and then its ELF interpreter.
  *  Note, we assume that the binary is a dynamically linked ELF shared object.
  */
-void* wld_start( void **stack )
+void* __attribute__((used)) wld_start( void **stack )
 {
     long i, *pargc;
     char **argv, **p;

[PATCH 2/2] loader: Mark thread_ldt, thread_data, wld_start "used".

[Marvin]

Hi,

It looks like your patch introduced the new failures shown below.
Please investigate and fix them before resubmitting your patch.
If they are not new, fixing them anyway would help a lot. Otherwise
please ask for the known failures list to be updated.

The tests also ran into some preexisting test failures. If you know how
to fix them that would be helpful. See the TestBot job for the details:

The full results can be found at:
https://testbot.winehq.org/JobDetails.pl?Key=150811

Your paranoid android.

=== debian11b (64 bit WoW report) ===

mshtml:
xmlhttprequest.c:460: Test failed: AllResponseHeaders(L"Date: Thu, 09 Jan 2025 08:09:24 GMT\r\nContent-Type: application/xml\r\nTransfer-Encoding: chunked\r\nConnection: keep-alive\r\nLast-Modified: Tue, 14 Jun 2022 15:45:18 GMT\r\nETag: W/"33-5e16a4aa23f18"\r\nCF-Cache-Status: DYNAMIC\r\nReport-To: {"endpoints":[{"url":"https:\/\/a.n"...) don't have expected substr(L"Content-Length: 51")
xmlhttprequest.c:460: Test failed: AllResponseHeaders(L"Date: Thu, 09 Jan 2025 08:09:25 GMT\r\nContent-Type: application/xml\r\nTransfer-Encoding: chunked\r\nConnection: keep-alive\r\nLast-Modified: Tue, 14 Jun 2022 15:45:18 GMT\r\nETag: W/"33-5e16a4aa23f18"\r\nCF-Cache-Status: DYNAMIC\r\nReport-To: {"endpoints":[{"url":"https:\/\/a.n"...) don't have expected substr(L"Content-Length: 51")

winhttp:
notification.c:734: Test failed: got unexpected thread 0xb94, err 0
winhttp.c:1205: Test failed: available_size = 542