From cf08675702044c180553c866ba1fde0414f00590 Mon Sep 17 00:00:00 2001
From: Joe Soroka <gits@joesoroka.com>
Date: Tue, 1 Feb 2011 09:41:03 -0800
Subject: [PATCH] weak definitions overrule non-weak prototypes

---
 tccgen.c        | 12 ++++++++++++
 tests/Makefile  | 11 +++++++++--
 tests/tcctest.c |  6 ++++++
 3 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/tccgen.c b/tccgen.c
index 2d7e4aec..7144ccdd 100644
--- a/tccgen.c
+++ b/tccgen.c
@@ -5194,6 +5194,12 @@ static void decl_initializer_alloc(CType *type, AttributeDef *ad, int r,
             vsetc(type, VT_CONST | VT_SYM, &cval);
             vtop->sym = sym;
         }
+        /* patch symbol weakness */
+        if (type->t & VT_WEAK) {
+            unsigned char *st_info = 
+                &((ElfW(Sym) *)symtab_section->data)[sym->c].st_info;
+            *st_info = ELF32_ST_INFO(STB_WEAK, ELF32_ST_TYPE(*st_info));
+        }
 #ifdef CONFIG_TCC_BCHECK
         /* handles bounds now because the symbol must be defined
            before for the relocation */
@@ -5314,6 +5320,12 @@ static void gen_function(Sym *sym)
     /* patch symbol size */
     ((ElfW(Sym) *)symtab_section->data)[sym->c].st_size = 
         ind - func_ind;
+    /* patch symbol weakness (this definition overrules any prototype) */
+    if (sym->type.t & VT_WEAK) {
+        unsigned char *st_info = 
+            &((ElfW(Sym) *)symtab_section->data)[sym->c].st_info;
+        *st_info = ELF32_ST_INFO(STB_WEAK, ELF32_ST_TYPE(*st_info));
+    }
     if (tcc_state->do_debug) {
         put_stabn(N_FUN, 0, 0, ind - func_ind);
     }
diff --git a/tests/Makefile b/tests/Makefile
index 017f35cf..4bebc2be 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -6,7 +6,7 @@
 TESTS = libtest test3
 
 # these should work too
-# TESTS += test1 test2 speedtest btest
+# TESTS += test1 test2 speedtest btest weaktest
 
 # these don't work as they should
 # TESTS += test4 asmtest
@@ -26,7 +26,7 @@ DISAS=objdump -d
 all test : $(TESTS)
 
 # make sure that tcc exists
-test1 test2 test3 test4 btest speedtest asmtest : ../tcc
+test1 test2 test3 test4 btest speedtest asmtest weaktest : ../tcc
 ../%:
 	$(MAKE) -C .. $*
 
@@ -116,6 +116,13 @@ speedtest: ex2 ex3
 	time ./ex3 35
 	time $(TCC) -run ../examples/ex3.c 35
 
+weaktest: test.ref
+	$(TCC) -c tcctest.c -o weaktest.tcc.o
+	 $(CC) -c tcctest.c -o weaktest.gcc.o -I. -w $(CFLAGS)
+	objdump -t weaktest.tcc.o | grep ' w ' | sed -e 's/.* \([a-zA-Z0-9_]*\)$$/\1/' | LC_ALL=C sort > weaktest.tcc.o.txt
+	objdump -t weaktest.gcc.o | grep ' w ' | sed -e 's/.* \([a-zA-Z0-9_]*\)$$/\1/' | LC_ALL=C sort > weaktest.gcc.o.txt
+	diff weaktest.gcc.o.txt weaktest.tcc.o.txt && echo "Weak Auto Test OK"
+
 ex%: ../examples/ex%.c
 	$(CC) -o $@ $< $(CFLAGS)
 
diff --git a/tests/tcctest.c b/tests/tcctest.c
index 8c2b2a25..01289575 100644
--- a/tests/tcctest.c
+++ b/tests/tcctest.c
@@ -2231,19 +2231,25 @@ void builtin_test(void)
 
 extern int __attribute__((weak)) weak_f1(void);
 extern int __attribute__((weak)) weak_f2(void);
+extern int                       weak_f3(void);
 extern int __attribute__((weak)) weak_v1;
 extern int __attribute__((weak)) weak_v2;
+extern int                       weak_v3;
 
 void __attribute__((weak)) weak_test(void)
 {
 	printf("weak_f1=%d\n", weak_f1 ? weak_f1() : 123);
 	printf("weak_f2=%d\n", weak_f2 ? weak_f2() : 123);
+	printf("weak_f3=%d\n", weak_f3 ? weak_f3() : 123);
 	printf("weak_v1=%d\n",&weak_v1 ? weak_v1   : 123);
 	printf("weak_v2=%d\n",&weak_v2 ? weak_v2   : 123);
+	printf("weak_v3=%d\n",&weak_v3 ? weak_v3   : 123);
 }
 
 int __attribute__((weak)) weak_f2() { return 222; }
+int __attribute__((weak)) weak_f3() { return 333; }
 int __attribute__((weak)) weak_v2 = 222;
+int __attribute__((weak)) weak_v3 = 333;
 
 void const_func(const int a)
 {
-- 
2.11.4.GIT