aarch64: override default elf .set handling in gas

Allow st_other values such as STO_AARCH64_VARIANT_PCS to be set for alias
symbols independently.  This is needed for ifunc symbols which are
aliased to the resolver using .set and don't expect resolver attributes
to override the ifunc symbol attributes.  This means .variant_pcs must be
added explicitly to aliases.

gas/ChangeLog:

	* config/tc-aarch64.c (aarch64_elf_copy_symbol_attributes): Define.
	* config/tc-aarch64.h (aarch64_elf_copy_symbol_attributes): Declare.
	(OBJ_COPY_SYMBOL_ATTRIBUTES): Define.
	* testsuite/gas/aarch64/symbol-variant_pcs-3.d: New test.
	* testsuite/gas/aarch64/symbol-variant_pcs-3.s: New test.

diff --git a/gas/ChangeLog b/gas/ChangeLog
index ed69e9a8126762aaf3247af39da4062ce5dfe2ce..a6a539c77a73a546ba7cc5400c04c6c8cc13c976 100644 (file)
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,11 @@
+2019-05-24  Szabolcs Nagy  <szabolcs.nagy@arm.com>
+
+       * config/tc-aarch64.c (aarch64_elf_copy_symbol_attributes): Define.
+       * config/tc-aarch64.h (aarch64_elf_copy_symbol_attributes): Declare.
+       (OBJ_COPY_SYMBOL_ATTRIBUTES): Define.
+       * testsuite/gas/aarch64/symbol-variant_pcs-3.d: New test.
+       * testsuite/gas/aarch64/symbol-variant_pcs-3.s: New test.
+
 2019-05-24  Szabolcs Nagy  <szabolcs.nagy@arm.com>
 
        * config/tc-aarch64.c (s_variant_pcs): New function.

diff --git a/gas/config/tc-aarch64.c b/gas/config/tc-aarch64.c
index 3bccfa24ba7412214a176e0ef47c1d3bb12ce9b7..000a81c64f8e95eef920fe447358f99bb68b84f9 100644 (file)
--- a/gas/config/tc-aarch64.c
+++ b/gas/config/tc-aarch64.c
@@ -9420,3 +9420,35 @@ aarch64_copy_symbol_attributes (symbolS * dest, symbolS * src)
 {
   AARCH64_GET_FLAG (dest) = AARCH64_GET_FLAG (src);
 }
+
+#ifdef OBJ_ELF
+/* Same as elf_copy_symbol_attributes, but without copying st_other.
+   This is needed so AArch64 specific st_other values can be independently
+   specified for an IFUNC resolver (that is called by the dynamic linker)
+   and the symbol it resolves (aliased to the resolver).  In particular,
+   if a function symbol has special st_other value set via directives,
+   then attaching an IFUNC resolver to that symbol should not override
+   the st_other setting.  Requiring the directive on the IFUNC resolver
+   symbol would be unexpected and problematic in C code, where the two
+   symbols appear as two independent function declarations.  */
+
+void
+aarch64_elf_copy_symbol_attributes (symbolS *dest, symbolS *src)
+{
+  struct elf_obj_sy *srcelf = symbol_get_obj (src);
+  struct elf_obj_sy *destelf = symbol_get_obj (dest);
+  if (srcelf->size)
+    {
+      if (destelf->size == NULL)
+       destelf->size = XNEW (expressionS);
+      *destelf->size = *srcelf->size;
+    }
+  else
+    {
+      if (destelf->size != NULL)
+       free (destelf->size);
+      destelf->size = NULL;
+    }
+  S_SET_SIZE (dest, S_GET_SIZE (src));
+}
+#endif

diff --git a/gas/config/tc-aarch64.h b/gas/config/tc-aarch64.h
index b54907218cf2cbe4ac72b875305d500fb4a46fbd..f4eb1d5fa976b50699f80927fd108d856e5b2806 100644 (file)
--- a/gas/config/tc-aarch64.h
+++ b/gas/config/tc-aarch64.h
@@ -130,6 +130,12 @@ void aarch64_copy_symbol_attributes (symbolS *, symbolS *);
   (aarch64_copy_symbol_attributes (DEST, SRC))
 #endif
 
+#ifdef OBJ_ELF
+void aarch64_elf_copy_symbol_attributes (symbolS *, symbolS *);
+#define OBJ_COPY_SYMBOL_ATTRIBUTES(DEST, SRC) \
+  aarch64_elf_copy_symbol_attributes (DEST, SRC)
+#endif
+
 #define TC_START_LABEL(STR, NUL_CHAR, NEXT_CHAR)                       \
   (NEXT_CHAR == ':' || (NEXT_CHAR == '/' && aarch64_data_in_code ()))
 #define tc_canonicalize_symbol_name(str) aarch64_canonicalize_symbol_name (str);

diff --git a/gas/testsuite/gas/aarch64/symbol-variant_pcs-3.d b/gas/testsuite/gas/aarch64/symbol-variant_pcs-3.d
new file mode 100644 (file)
index 0000000..204914e
--- /dev/null
+++ b/gas/testsuite/gas/aarch64/symbol-variant_pcs-3.d
@@ -0,0 +1,12 @@
+#objdump: -t
+
+.*:     file format .*
+
+SYMBOL TABLE:
+0+ l    d  \.text      0+ \.text
+0+ l    d  \.data      0+ \.data
+0+ l    d  \.bss       0+ \.bss
+0+ g       \.text      0+ 0x80 foo_vpcs
+0+ g       \.text      0+ foo_base
+0+ g       \.text      0+ 0x80 alias_vpcs
+0+ g       \.text      0+ alias_base

diff --git a/gas/testsuite/gas/aarch64/symbol-variant_pcs-3.s b/gas/testsuite/gas/aarch64/symbol-variant_pcs-3.s
new file mode 100644 (file)
index 0000000..9960831
--- /dev/null
+++ b/gas/testsuite/gas/aarch64/symbol-variant_pcs-3.s
@@ -0,0 +1,20 @@
+.text
+.global foo_vpcs
+.global foo_base
+.global alias_vpcs
+.global alias_base
+
+.variant_pcs foo_vpcs
+.variant_pcs alias_vpcs
+
+foo_vpcs:
+foo_base:
+       bl foo_vpcs
+       bl foo_base
+       bl alias_vpcs
+       bl alias_base
+
+/* Check that the STO_AARCH64_VARIANT_PCS is not affected by .set.  */
+
+.set alias_base, foo_vpcs
+.set alias_vpcs, foo_base