[PATCH] winebuild: Find main/wmain in static libraries. - wine-devel

17 Jul 2020

Have the winebuild -spec.o include an undefined .globl referencing any
symbol we know the winecrt0 entry point will eventually reference,
so ld knows about what it needs before scanning library archives.
---
wine.exe.so files set __wine_spec_exe_entry as the entry point,
rather than main. Therefore the linker is not initially looking for main,
and will pass over any objects in lib.a archives that might provide it.
When libwinecrt0.a is reached, it finds __wine_spec_exe_entry and learns
that this wants main, but this rescan will prefer the winecrt0 definition
(in terms of WinMain) to rescanning earlier libraries.
Only a direct .o file (which is never passed over) can override this,
so libraries like -lgtest_main do not work as intended.

diff --git a/tools/winebuild/build.h b/tools/winebuild/build.h
index e1d2e5edf8..66b15167a3 100644
--- a/tools/winebuild/build.h
+++ b/tools/winebuild/build.h
@@ -136,6 +136,7 @@ typedef struct
     int              subsystem;          /* subsystem id */
     int              subsystem_major;    /* subsystem version major number */
     int              subsystem_minor;    /* subsystem version minor number */
+    int              unicode_app;        /* default to unicode entry point */
     ORDDEF          *entry_points;       /* dll entry points */
     ORDDEF         **names;              /* array of entry point names (points into entry_points) */
     ORDDEF         **ordinals;           /* array of dll ordinals (points into entry_points) */
@@ -297,6 +298,7 @@ extern void output_gnu_stack_note(void);
extern void add_import_dll( const char *name, const char *filename );
extern void add_delayed_import( const char *name );
extern void add_extra_ld_symbol( const char *name );
+extern void add_spec_extra_ld_symbol( const char *name );
extern void read_undef_symbols( DLLSPEC *spec, char **argv );
extern void resolve_imports( DLLSPEC *spec );
extern int is_undefined( const char *name );
diff --git a/tools/winebuild/main.c b/tools/winebuild/main.c
index 0e5e1627dd..68137b0f4c 100644
--- a/tools/winebuild/main.c
+++ b/tools/winebuild/main.c
@@ -396,8 +396,25 @@ static const char *get_default_entry_point( const DLLSPEC *spec )
{
     if (spec->characteristics & IMAGE_FILE_DLL) return "DllMain";
     if (spec->subsystem == IMAGE_SUBSYSTEM_NATIVE) return "DriverEntry";
-    if (spec->type == SPEC_WIN16) return "__wine_spec_exe16_entry";
-    return "__wine_spec_exe_entry";
+    if (spec->type == SPEC_WIN16) {
+        add_spec_extra_ld_symbol("WinMain16");
+        return "__wine_spec_exe16_entry";
+    }
+    if (spec->unicode_app) {
+        /* __wine_spec_exe_wentry always calls wmain */
+        add_spec_extra_ld_symbol("wmain");
+        if(spec->subsystem == IMAGE_SUBSYSTEM_WINDOWS_GUI) {
+            add_spec_extra_ld_symbol("wWinMain");
+        }
+        return "__wine_spec_exe_wentry";
+    } else {
+        /* __wine_spec_exe_entry always calls main */
+        add_spec_extra_ld_symbol("main");
+        if(spec->subsystem == IMAGE_SUBSYSTEM_WINDOWS_GUI) {
+            add_spec_extra_ld_symbol("WinMain");
+        }
+        return "__wine_spec_exe_entry";
+    }
}
 /* parse options from the argv array and remove all the recognized ones */
@@ -448,6 +465,7 @@ static char **parse_options( int argc, char **argv, DLLSPEC *spec )
             else if (!strcmp( optarg, "thumb" )) thumb_mode = 1;
             else if (!strcmp( optarg, "no-cygwin" )) use_msvcrt = 1;
             else if (!strcmp( optarg, "unix" )) unix_lib = 1;
+            else if (!strcmp( optarg, "unicode" )) spec->unicode_app = 1;
             else if (!strncmp( optarg, "cpu=", 4 )) cpu_option = xstrdup( optarg + 4 );
             else if (!strncmp( optarg, "fpu=", 4 )) fpu_option = xstrdup( optarg + 4 );
             else if (!strncmp( optarg, "arch=", 5 )) arch_option = xstrdup( optarg + 5 );
diff --git a/tools/winebuild/spec32.c b/tools/winebuild/spec32.c
index c85249b2a9..7fccb0c4f6 100644
--- a/tools/winebuild/spec32.c
+++ b/tools/winebuild/spec32.c
@@ -50,6 +50,13 @@ int needs_get_pc_thunk = 0;
 static const char builtin_signature[32] = "Wine builtin DLL";
static const char fakedll_signature[32] = "Wine placeholder DLL";
+static struct strarray spec_extra_ld_symbols = { 0 }; /* list of extra symbols that ld should resolve */
+
+/* add a symbol to the list of extra symbols that ld must resolve */
+void add_spec_extra_ld_symbol( const char *name )
+{
+    strarray_add( &spec_extra_ld_symbols, name, NULL );
+}
 /* check if entry point needs a relay thunk */
static inline int needs_relay( const ORDDEF *odp )
@@ -602,6 +609,7 @@ void output_exports( DLLSPEC *spec )
void output_module( DLLSPEC *spec )
{
     int machine = 0;
+    int i;
     unsigned int page_size = get_page_size();
     const char *data_dirs[16] = { NULL };
@@ -680,6 +688,10 @@ void output_module( DLLSPEC *spec )
     output( "\t.long 0\n" );              /* SizeOfCode */
     output( "\t.long 0\n" );              /* SizeOfInitializedData */
     output( "\t.long 0\n" );              /* SizeOfUninitializedData */
+
+    for (i = 0; i < spec_extra_ld_symbols.count; i++)
+        output( "\t.globl %s\n", asm_name(spec_extra_ld_symbols.str[i]) );
+
     /* note: we expand the AddressOfEntryPoint field on 64-bit by overwriting the BaseOfCode field */
     output( "\t%s %s\n",                  /* AddressOfEntryPoint */
             get_asm_ptr_keyword(), spec->init_func ? asm_name(spec->init_func) : "0" );
diff --git a/tools/winegcc/winegcc.c b/tools/winegcc/winegcc.c
index 29c1b0549d..3c2b029b40 100644
--- a/tools/winegcc/winegcc.c
+++ b/tools/winegcc/winegcc.c
@@ -1228,8 +1228,6 @@ static void build(struct options* opts)
             entry_point = (is_pe && opts->target_cpu == CPU_x86) ? "DriverEntry@8" : "DriverEntry";
         else if (opts->use_msvcrt && !opts->shared && !opts->win16_app)
             entry_point = opts->unicode_app ? "wmainCRTStartup" : "mainCRTStartup";
-        else if (!is_pe && !opts->shared && opts->unicode_app)
-            entry_point = "__wine_spec_exe_wentry";
     }
     else entry_point = opts->entry_point;
@@ -1241,6 +1239,8 @@ static void build(struct options* opts)
     spec_o_name = get_temp_file(output_name, ".spec.o");
     if (opts->force_pointer_size)
         strarray_add(spec_args, strmake("-m%u", 8 * opts->force_pointer_size ));
+    if(opts->unicode_app)
+        strarray_add(spec_args, "-municode");
     strarray_add(spec_args, "-D_REENTRANT");
     if (opts->pic && !is_pe) strarray_add(spec_args, "-fPIC");
     strarray_add(spec_args, opts->shared ? "--dll" : "--exe");

    