PATCH: PR ld/10426: ld incorrectly creates STT_GNU_IFUNC SHN_UNDEF symbols

H.J. Lu hongjiu.lu@intel.com
Wed Jul 22 11:46:00 GMT 2009


Hi,

For static linker, a STT_GNU_IFUNC symbol in a DSO is the same as a normal
FUNC symbol.  Also, there should be no undefined STT_GNU_IFUNC symbol in
output.  I am checking in this patch as an obvious fix.

Thanks.


H.J.
---
Index: ld/testsuite/ChangeLog
===================================================================
--- ld/testsuite/ChangeLog	(revision 6446)
+++ ld/testsuite/ChangeLog	(working copy)
@@ -1,3 +1,11 @@
+2009-07-21  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR ld/10426
+	* ld-ifunc/ifunc.exp: Check test-1 and libtest-2.so.  Updated.
+
+	* ld-ifunc/test-1.c: New.
+	* ld-ifunc/test-2.c: Likewise.
+
 2009-07-17  Chao-ying Fu  <fu@mips.com>
 
 	* ld-mips-elf/pic-and-nonpic-3b.dd: Updated to use new PLT
Index: ld/testsuite/ld-ifunc/ifunc.exp
===================================================================
--- ld/testsuite/ld-ifunc/ifunc.exp	(revision 6446)
+++ ld/testsuite/ld-ifunc/ifunc.exp	(working copy)
@@ -181,6 +181,14 @@ if ![ld_assemble $as "$srcdir/ld-elf/emp
     fail "Could not create an empty object file"
     set fails [expr $fails + 1]
 }
+if ![ld_compile "$CC -c" "$srcdir/$subdir/test-1.c" "tmpdir/test-1.o"] {
+    fail "Could not create test-1.o"
+    set fails [expr $fails + 1]
+}
+if ![ld_compile "$CC -fPIC -c" "$srcdir/$subdir/test-2.c" "tmpdir/test-2.o"] {
+    fail "Could not create test-2.o"
+    set fails [expr $fails + 1]
+}
 
 if { $fails != 0 } {
     return
@@ -215,6 +223,14 @@ if ![ld_simple_link $ld "tmpdir/static_n
     fail "Could not link a non-ifunc using static executable"
     set fails [expr $fails + 1]
 }
+if ![default_ld_link $ld "tmpdir/test-1" "tmpdir/test-1.o tmpdir/libshared_ifunc.so"] {
+    fail "Could not link test-1"
+    set fails [expr $fails + 1]
+}
+if ![ld_simple_link $ld "tmpdir/libtest-2.so" "-shared tmpdir/test-2.o"] {
+    fail "Could not link libtest-2.so"
+    set fails [expr $fails + 1]
+}
 
 if { $fails == 0 } {
   pass "Building ifunc binaries"
@@ -266,14 +282,22 @@ if {[contains_ifunc_symbol tmpdir/static
     fail "Static ifunc-using executable does not contain an IFUNC symbol"
     set fails [expr $fails + 1]
 }
-if {[contains_ifunc_symbol tmpdir/dynamic_prog] != 1} {
-    fail "Dynamic ifunc-using executable does not contain an IFUNC symbol"
+if {[contains_ifunc_symbol tmpdir/dynamic_prog] != 0} {
+    fail "Dynamic ifunc-using executable contains an IFUNC symbol"
     set fails [expr $fails + 1]
 }
 if {[contains_ifunc_symbol tmpdir/static_nonifunc_prog] != 0} {
     fail "Static non-ifunc-using executable contains an IFUNC symbol"
     set fails [expr $fails + 1]
 }
+if {[contains_ifunc_symbol tmpdir/test-1] != 0} {
+    fail "test-1 contains IFUNC symbols"
+    set fails [expr $fails + 1]
+}
+if {[contains_ifunc_symbol tmpdir/libtest-2.so] != 0} {
+    fail "libtest-2.so contains IFUNC symbols"
+    set fails [expr $fails + 1]
+}
 
 # The linked ifunc using executables and shared libraries should contain
 # a dynamic reloc referencing the IFUNC symbol.  (Even the static
@@ -292,8 +316,8 @@ if {[contains_irelative_reloc tmpdir/sta
     fail "Static ifunc-using executable does not contain R_*_IRELATIVE relocation"
     set fails [expr $fails + 1]
 }
-if {[contains_ifunc_reloc tmpdir/dynamic_prog] != 1} {
-    fail "Dynamic ifunc-using executable does not contain a reloc against an IFUNC symbol"
+if {[contains_ifunc_reloc tmpdir/dynamic_prog] != 0} {
+    fail "Dynamic ifunc-using executable contains a reloc against an IFUNC symbol"
     set fails [expr $fails + 1]
 }
 if {[contains_ifunc_reloc tmpdir/static_nonifunc_prog] == 1} {
Index: ld/testsuite/ld-ifunc/test-1.c
===================================================================
--- ld/testsuite/ld-ifunc/test-1.c	(revision 0)
+++ ld/testsuite/ld-ifunc/test-1.c	(revision 0)
@@ -0,0 +1,3 @@
+extern int library_func2 (void);
+int (*fn) (void) = library_func2;
+int main (void) { fn (); return 0; }
Index: ld/testsuite/ld-ifunc/test-2.c
===================================================================
--- ld/testsuite/ld-ifunc/test-2.c	(revision 0)
+++ ld/testsuite/ld-ifunc/test-2.c	(revision 0)
@@ -0,0 +1,3 @@
+extern int library_func2 (void);
+int foo (void) { library_func2 (); return 0; }
+__asm__(".type library_func2, %gnu_indirect_function");
Index: bfd/ChangeLog
===================================================================
--- bfd/ChangeLog	(revision 6446)
+++ bfd/ChangeLog	(working copy)
@@ -1,3 +1,11 @@
+2009-07-21  H.J. Lu  <hongjiu.lu@intel.com>
+
+	 PR ld/10426
+	 * elflink.c (elf_link_add_object_symbols): Turn an IFUNC symbol
+	 from a DSO into a normal FUNC symbol.
+	 (elf_link_output_extsym): Turn an undefined IFUNC symbol into
+	 a normal FUNC symbol.
+
 2009-07-17  Chao-ying Fu  <fu@mips.com>
 
 	* elfxx-mips.c (LOAD_INTERLOCKS_P): New define.
Index: bfd/elflink.c
===================================================================
--- bfd/elflink.c	(revision 6446)
+++ bfd/elflink.c	(working copy)
@@ -4279,15 +4279,24 @@ error_free_dyn:
 	  if (ELF_ST_TYPE (isym->st_info) != STT_NOTYPE
 	      && (definition || h->type == STT_NOTYPE))
 	    {
-	      if (h->type != STT_NOTYPE
-		  && h->type != ELF_ST_TYPE (isym->st_info)
-		  && ! type_change_ok)
-		(*_bfd_error_handler)
-		  (_("Warning: type of symbol `%s' changed"
-		     " from %d to %d in %B"),
-		   abfd, name, h->type, ELF_ST_TYPE (isym->st_info));
+	      unsigned int type = ELF_ST_TYPE (isym->st_info);
+
+	      /* Turn an IFUNC symbol from a DSO into a normal FUNC
+		 symbol.  */
+	      if (type == STT_GNU_IFUNC
+		  && (abfd->flags & DYNAMIC) != 0)
+		type = STT_FUNC;
 
-	      h->type = ELF_ST_TYPE (isym->st_info);
+	      if (h->type != type)
+		{
+		  if (h->type != STT_NOTYPE && ! type_change_ok)
+		    (*_bfd_error_handler)
+		      (_("Warning: type of symbol `%s' changed"
+			 " from %d to %d in %B"),
+		       abfd, name, h->type, type);
+
+		  h->type = type;
+		}
 	    }
 
 	  /* Merge st_other field.  */
@@ -8683,12 +8692,17 @@ elf_link_output_extsym (struct elf_link_
 	  || ELF_ST_BIND (sym.st_info) == STB_WEAK))
     {
       int bindtype;
+      unsigned int type = ELF_ST_TYPE (sym.st_info);
+
+      /* Turn an undefined IFUNC symbol into a normal FUNC symbol. */
+      if (type == STT_GNU_IFUNC)
+	type = STT_FUNC;
 
       if (h->ref_regular_nonweak)
 	bindtype = STB_GLOBAL;
       else
 	bindtype = STB_WEAK;
-      sym.st_info = ELF_ST_INFO (bindtype, ELF_ST_TYPE (sym.st_info));
+      sym.st_info = ELF_ST_INFO (bindtype, type);
     }
 
   /* If this is a symbol defined in a dynamic library, don't use the



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