[PATCH v2 0/1] MR3873: tools/winebuild: Force CIE content on x86_64.

[eric pouech (＠epo)]

Force as to emit expected CIE/FDE information for x86_64 CPU
in .debug_frame section.

This has been unveiled by 425bd55b02e375b9ac8f79b254ce3ca5c9e72719
(before this commit, the .cfi directives where not emitted by
winebuild).

x86_64-w64-mingw32-as on x86_64 emits "strange" unwinding
information (from winebuild).

00000000 0000000000000014 ffffffff CIE
  Version:               1
  Augmentation:          ""
  Code alignment factor: 1
  Data alignment factor: -8
  Return address column: 32

DW_CFA_def_cfa: r7 (rsp) ofs 8
  DW_CFA_offset: r32 (xmm15) at cfa-8
  DW_CFA_nop
  DW_CFA_nop
  DW_CFA_nop
  DW_CFA_nop
  DW_CFA_nop
  DW_CFA_nop

Consequence: in unwinding, xmm15 gets updated, but rip isn't, causing
an infinite loop in dbghelp.

Wine-Bug-Id: https://bugs.winehq.org/show_bug.cgi?id=55560

Signed-off-by: Eric Pouech

--
  v2: tools/winebuild: Emit SEH unwind information instead of dwarf.

https://gitlab.winehq.org/wine/wine/-/merge_requests/3873

[PATCH v2 1/1] tools/winebuild: Emit SEH unwind information instead of dwarf.

[Eric Pouech]

From: Eric Pouech

Done for syscall and import thunks on PE targets.

Wine-Bug-Id: https://bugs.winehq.org/show_bug.cgi?id=55560

Signed-off-by: Eric Pouech 
---
 tools/winebuild/build.h  |  2 ++
 tools/winebuild/import.c |  8 ++++----
 tools/winebuild/utils.c  | 13 +++++++++++++
 3 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/tools/winebuild/build.h b/tools/winebuild/build.h
index 733cd34e614..dfa8574a5da 100644
--- a/tools/winebuild/build.h
+++ b/tools/winebuild/build.h
@@ -246,6 +246,8 @@ extern int output( const char *format, ... )
    __attribute__ ((__format__ (__printf__, 1, 2)));
 extern void output_cfi( const char *format, ... )
    __attribute__ ((__format__ (__printf__, 1, 2)));
+extern void output_seh( const char *format, ... )
+   __attribute__ ((__format__ (__printf__, 1, 2)));
 extern void output_rva( const char *format, ... )
    __attribute__ ((__format__ (__printf__, 1, 2)));
 extern void output_thunk_rva( int ordinal, const char *format, ... )
diff --git a/tools/winebuild/import.c b/tools/winebuild/import.c
index de4bc26f60d..6d0642fdb28 100644
--- a/tools/winebuild/import.c
+++ b/tools/winebuild/import.c
@@ -769,7 +769,7 @@ static void output_import_thunk( const char *name, const char *table, int pos )
     output( "\n\t.align %d\n", get_alignment(4) );
     output( "\t%s\n", func_declaration(name) );
     output( "%s\n", asm_globl(name) );
-    output_cfi( ".cfi_startproc" );
+    output_seh( ".seh_proc %s", asm_name(name) );

switch (target.cpu)
     {
@@ -811,7 +811,7 @@ static void output_import_thunk( const char *name, const char *table, int pos )
         output( "\tbr x16\n" );
         break;
     }
-    output_cfi( ".cfi_endproc" );
+    output_seh( ".seh_endproc" );
     output_function_size( name );
 }

@@ -1421,7 +1421,7 @@ void output_syscalls( DLLSPEC *spec )
         output( "\t.align %d\n", get_alignment(16) );
         output( "\t%s\n", func_declaration(name) );
         output( "%s\n", asm_globl(name) );
-        output_cfi( ".cfi_startproc" );
+        output_seh( ".seh_proc %s", asm_name(name) );
         switch (target.cpu)
         {
         case CPU_i386:
@@ -1483,7 +1483,7 @@ void output_syscalls( DLLSPEC *spec )
         default:
             assert(0);
         }
-        output_cfi( ".cfi_endproc" );
+        output_seh( ".seh_endproc" );
         output_function_size( name );
     }

diff --git a/tools/winebuild/utils.c b/tools/winebuild/utils.c
index 49d2468b236..41e3462bfb2 100644
--- a/tools/winebuild/utils.c
+++ b/tools/winebuild/utils.c
@@ -938,6 +938,19 @@ void output_cfi( const char *format, ... )
     va_end( valist );
 }

+/* output a .seh directive */
+void output_seh( const char *format, ... )
+{
+    va_list valist;
+
+    if (!unwind_tables || target.cpu == CPU_i386) return;
+    va_start( valist, format );
+    fputc( '\t', output_file );
+    vfprintf( output_file, format, valist );
+    fputc( '\n', output_file );
+    va_end( valist );
+}
+
 /* output an RVA pointer */
 void output_rva( const char *format, ... )
 {