tcc_attribute_naked.patch

From 7050d61d1c8a14077d0399ad5a7422aad16b79a8 Mon Sep 17 00:00:00 2001
From: Stefan Koch <[email protected]>
Date: Tue, 8 Feb 2022 11:14:38 +0100
Subject: [PATCH] Add __attribute__(naked)

---
 tcc.h    |  3 ++-
 tccgen.c | 13 +++++++++++--
 tcctok.h |  1 +
 3 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/tcc.h b/tcc.h
index ef69ef5..e8ed61d 100644
--- a/tcc.h
+++ b/tcc.h
@@ -548,7 +548,8 @@ struct FuncAttr {
     func_dtor   : 1, /* attribute((destructor)) */
     func_args   : 8, /* PE __stdcall args */
     func_alwinl : 1, /* always_inline */
-    xxxx        : 15;
+    func_naked  : 1,  /* attribute((naked)) */
+    xxxx        : 14;
 };
 
 /* symbol management */
diff --git a/tccgen.c b/tccgen.c
index 67e205b..18ac832 100644
--- a/tccgen.c
+++ b/tccgen.c
@@ -81,6 +81,7 @@ ST_DATA int global_expr;  /* true if compound literals must be allocated globall
 ST_DATA CType func_vt; /* current function return type (used by return instruction) */
 ST_DATA int func_var; /* true if current function is variadic (used by return instruction) */
 ST_DATA int func_vc;
+ST_DATA int func_naked;
 static int last_line_num, new_file, func_ind; /* debug info control */
 ST_DATA const char *funcname;
 ST_DATA CType int_type, func_old_type, char_type, char_pointer_type;
@@ -1686,6 +1687,8 @@ static void merge_funcattr(struct FuncAttr *fa, struct FuncAttr *fa1)
       fa->func_args = fa1->func_args;
     if (fa1->func_noreturn)
       fa->func_noreturn = 1;
+    if (fa1->func_naked)
+      fa->func_naked = 1;
     if (fa1->func_ctor)
       fa->func_ctor = 1;
     if (fa1->func_dtor)
@@ -4432,6 +4435,9 @@ redo:
         case TOK_NORETURN2:
             ad->f.func_noreturn = 1;
             break;
+        case TOK_NAKED:
+            ad->f.func_naked = 1;
+            break;
         case TOK_CDECL1:
         case TOK_CDECL2:
         case TOK_CDECL3:
@@ -8602,13 +8608,15 @@ static void gen_function(Sym *sym)
     func_ind = ind;
     func_vt = sym->type.ref->type;
     func_var = sym->type.ref->f.func_type == FUNC_ELLIPSIS;
+    func_naked = sym->type.ref->f.func_naked;
 
     /* put debug symbol */
     tcc_debug_funcstart(tcc_state, sym);
     /* push a dummy symbol to enable local sym storage */
     sym_push2(&local_stack, SYM_FIELD, 0, 0);
     local_scope = 1; /* for function parameters */
-    gfunc_prolog(sym);
+    if (func_naked != 1)
+        gfunc_prolog(sym);
     local_scope = 0;
     rsym = 0;
     clear_temp_local_var_list();
@@ -8617,7 +8625,8 @@ static void gen_function(Sym *sym)
     nocode_wanted = 0;
     /* reset local stack */
     pop_local_syms(NULL, 0);
-    gfunc_epilog();
+    if (func_naked != 1)
+        gfunc_epilog();
     cur_text_section->data_offset = ind;
     local_scope = 0;
     label_pop(&global_label_stack, NULL, 0);
diff --git a/tcctok.h b/tcctok.h
index d4c1ef5..7eff548 100644
--- a/tcctok.h
+++ b/tcctok.h
@@ -140,6 +140,7 @@
      DEF(TOK_DESTRUCTOR2, "__destructor__")
      DEF(TOK_ALWAYS_INLINE1, "always_inline")
      DEF(TOK_ALWAYS_INLINE2, "__always_inline__")
+     DEF(TOK_NAKED, "naked")
 
      DEF(TOK_MODE, "__mode__")
      DEF(TOK_MODE_QI, "__QI__")
-- 
2.17.1