XCOFF: add support for TLS relocations on hidden symbols

This patch adds support for TLS relocation targeting C_HIDEXT symbols.
In gas, TLS relocations, except R_TLSM and R_TLMSL, must keep the value
of their target symbol.
In ld, it simply ensures that internal TLS symbols are added to the
linker hash table for xcoff_reloc_type_tls.

It also improves the tests made by both.

bfd/ChangeLog:

	* coff-rs6000.c (xcoff_howto_table): Fix name of R_TLSML.
	(xcoff_reloc_type_tls): Replace the error when h is NULL by
	an assert.
	(xcoff_complain_overflow_unsigned_func): Adjust comments.
	* coff64-rs6000.c (xcoff64_howto_table): Fix name of R_TLSML.
	* xcofflink.c (xcoff_link_add_symbols_to_hash_table): New
	function.
	(xcoff_link_add_symbols): Add C_HIDEXT TLS symbols to the linker
	hash table.

gas/ChangeLog:

	* config/tc-ppc.c (md_apply_fix): Enable support for TLS
	relocation over internal symbols.
	* testsuite/gas/ppc/aix.exp: Replace xcoff-tlms by xcoff-tls.
	* testsuite/gas/ppc/xcoff-tlsm-32.d: Removed.
	* testsuite/gas/ppc/xcoff-tlsm-64.d: Removed.
	* testsuite/gas/ppc/xcoff-tlsm.s: Removed.
	* testsuite/gas/ppc/xcoff-tls-32.d: New test.
	* testsuite/gas/ppc/xcoff-tls-64.d: New test.
	* testsuite/gas/ppc/xcoff-tls.s: New test.

ld/ChangeLog:

	* testsuite/ld-powerpc/aix52.exp: Improve aix-tls-reloc test.
	* testsuite/ld-powerpc/aix-tls-reloc.s: Likewise.
	* testsuite/ld-powerpc/aix-tls-reloc-32.d: Removed.
	* testsuite/ld-powerpc/aix-tls-reloc-64.d: Removed.
	* testsuite/ld-powerpc/aix-tls-reloc-32.dd: New test.
	* testsuite/ld-powerpc/aix-tls-reloc-32.dt: New test.
	* testsuite/ld-powerpc/aix-tls-reloc-64.dd: New test.
	* testsuite/ld-powerpc/aix-tls-reloc-64.dt: New test.

3 files changed, 62 insertions, 28 deletions

diff --git a/bfd/coff-rs6000.c b/bfd/coff-rs6000.c
index 3248670..97e84a4 100644
--- a/bfd/coff-rs6000.c
+++ b/bfd/coff-rs6000.c
@@ -1106,7 +1106,7 @@ reloc_howto_type xcoff_howto_table[] =
 	 0,			/* bitpos */
 	 complain_overflow_bitfield, /* complain_on_overflow */
 	 0,			/* special_function */
-	 "R_TLSM",		/* name */
+	 "R_TLSML",		/* name */
 	 true,			/* partial_inplace */
 	 0xffffffff,		/* src_mask */
 	 0xffffffff,		/* dst_mask */
@@ -3236,27 +3236,19 @@ xcoff_reloc_type_tls (bfd *input_bfd ATTRIBUTE_UNUSED,
 
   h = obj_xcoff_sym_hashes (input_bfd)[rel->r_symndx];
 
-  /* FIXME: R_TLSML is targeting a internal TOC symbol, which will
-     make the following checks failing. It should be moved with
-     R_TLSM bellow once it works.  */
+  /* R_TLSML is handled by the loader but must be from a
+     TOC entry targeting itslef.  This is already verified in
+     xcoff_link_add_symbols.
+     The value must be 0.  */
   if (howto->type == R_TLSML)
     {
       *relocation = 0;
       return true;
     }
 
-  /* FIXME: h is sometimes null, if the TLS symbol is not exported.  */
-  if (!h)
-    {
-      char vaddr_buf[128];
-
-      sprintf_vma (vaddr_buf, rel->r_vaddr);
-      _bfd_error_handler
-	(_("%pB: TLS relocation at 0x%s over internal symbols (C_HIDEXT) not yet possible\n"),
-	 input_bfd, vaddr_buf);
-      return false;
-    }
-
+  /* The target symbol should always be available even if it's not
+     exported.  */
+  BFD_ASSERT (h != NULL);
 
   /* TLS relocations must target a TLS symbol.  */
   if (h->smclas != XMC_TL && h->smclas != XMC_UL)
@@ -3286,9 +3278,8 @@ xcoff_reloc_type_tls (bfd *input_bfd ATTRIBUTE_UNUSED,
       return false;
     }
 
-  /* R_TLSM and R_TLSML are relocations used by the loader.
-     The value must be 0.
-     FIXME: move R_TLSML here.  */
+  /* R_TLSM are relocations used by the loader.
+     The value must be 0.  */
   if (howto->type == R_TLSM)
     {
       *relocation = 0;
@@ -3621,10 +3612,10 @@ xcoff_complain_overflow_unsigned_func (bfd *input_bfd,
    R_TLS_LE:
    Thread-local storage relocation using local-exec model.
 
-   R_TLS:
+   R_TLSM:
    Tread-local storage relocation used by the loader.
 
-   R_TLSM:
+   R_TLSML:
    Tread-local storage relocation used by the loader.
 
    R_TOCU:
diff --git a/bfd/coff64-rs6000.c b/bfd/coff64-rs6000.c
index 6698f43..01326d4 100644
--- a/bfd/coff64-rs6000.c
+++ b/bfd/coff64-rs6000.c
@@ -1350,7 +1350,7 @@ reloc_howto_type xcoff64_howto_table[] =
 	 0,			/* bitpos */
 	 complain_overflow_bitfield, /* complain_on_overflow */
 	 0,			/* special_function */
-	 "R_TLSM",		/* name */
+	 "R_TLSML",		/* name */
 	 true,			/* partial_inplace */
 	 MINUS_ONE,		/* src_mask */
 	 MINUS_ONE,		/* dst_mask */
diff --git a/bfd/xcofflink.c b/bfd/xcofflink.c
index a838c4b..ba07ba7 100644
--- a/bfd/xcofflink.c
+++ b/bfd/xcofflink.c
@@ -1178,6 +1178,26 @@ xcoff_find_reloc (struct internal_reloc *relocs,
   return min;
 }
 
+/* Return true if the symbol has to be added to the linker hash
+   table.  */
+static bool
+xcoff_link_add_symbols_to_hash_table (struct internal_syment sym,
+				      union internal_auxent aux)
+{
+  /* External symbols must be added.  */
+  if (EXTERN_SYM_P (sym.n_sclass))
+    return true;
+
+  /* Hidden TLS symbols must be added to verify TLS relocations
+     in xcoff_reloc_type_tls.  */
+  if (sym.n_sclass == C_HIDEXT
+      && ((aux.x_csect.x_smclas == XMC_TL
+	   || aux.x_csect.x_smclas == XMC_UL)))
+    return true;
+
+  return false;
+}
+
 /* Add all the symbols from an object file to the hash table.
 
    XCOFF is a weird format.  A normal XCOFF .o files will have three
@@ -1551,6 +1571,11 @@ xcoff_link_add_symbols (bfd *abfd, struct bfd_link_info *info)
 	     32 bit has a csect length of 4 for TOC
 	     64 bit has a csect length of 8 for TOC
 
+	     An exception is made for TOC entries with a R_TLSML
+	     relocation.  This relocation is made for the loader.
+	     We must check that the referenced symbol is the TOC entry
+	     itself.
+
 	     The conditions to get past the if-check are not that bad.
 	     They are what is used to create the TOC csects in the first
 	     place.  */
@@ -1580,7 +1605,8 @@ xcoff_link_add_symbols (bfd *abfd, struct bfd_link_info *info)
 		 64 bit R_POS r_size is 63  */
 	      if (relindx < enclosing->reloc_count
 		  && rel->r_vaddr == (bfd_vma) sym.n_value
-		  && rel->r_type == R_POS
+		  && (rel->r_type == R_POS ||
+		      rel->r_type == R_TLSML)
 		  && ((bfd_xcoff_is_xcoff32 (abfd)
 		       && rel->r_size == 31)
 		      || (bfd_xcoff_is_xcoff64 (abfd)
@@ -1652,6 +1678,22 @@ xcoff_link_add_symbols (bfd *abfd, struct bfd_link_info *info)
 			  set_toc = h;
 			}
 		    }
+		  else if (rel->r_type == R_TLSML)
+		    {
+			csect_index = ((esym
+					- (bfd_byte *) obj_coff_external_syms (abfd))
+				       / symesz);
+			if (((unsigned long) rel->r_symndx) != csect_index)
+			  {
+			    _bfd_error_handler
+			      /* xgettext:c-format */
+			      (_("%pB: TOC entry `%s' has a R_TLSML"
+				 "relocation not targeting itself"),
+			       abfd, name);
+			    bfd_set_error (bfd_error_bad_value);
+			    goto error_return;
+			  }
+		    }
 		}
 	    }
 
@@ -1749,9 +1791,10 @@ xcoff_link_add_symbols (bfd *abfd, struct bfd_link_info *info)
 	    if (first_csect == NULL)
 	      first_csect = csect;
 
-	    /* If this symbol is external, we treat it as starting at the
-	       beginning of the newly created section.  */
-	    if (EXTERN_SYM_P (sym.n_sclass))
+	    /* If this symbol must be added to the linker hash table,
+	       we treat it as starting at the beginning of the newly
+	       created section.  */
+	    if (xcoff_link_add_symbols_to_hash_table (sym, aux))
 	      {
 		section = csect;
 		value = 0;
@@ -1847,7 +1890,7 @@ xcoff_link_add_symbols (bfd *abfd, struct bfd_link_info *info)
 	  if (first_csect == NULL)
 	    first_csect = csect;
 
-	  if (EXTERN_SYM_P (sym.n_sclass))
+	  if (xcoff_link_add_symbols_to_hash_table (sym, aux))
 	    {
 	      csect->flags |= SEC_IS_COMMON;
 	      csect->size = 0;
@@ -1888,7 +1931,7 @@ xcoff_link_add_symbols (bfd *abfd, struct bfd_link_info *info)
       /* Now we have enough information to add the symbol to the
 	 linker hash table.  */
 
-      if (EXTERN_SYM_P (sym.n_sclass))
+      if (xcoff_link_add_symbols_to_hash_table (sym, aux))
 	{
 	  bool copy, ok;
 	  flagword flags;