aarch64: override default elf .set handling in gas

Backport commit 0b4eac57c44ec4c9e13f5201b40936c3b3e6c639

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 c6a65ac94271d8ce718b5391a6afe393e7407e6f..f5c03a91c00b6c0a72ca462b788c3aa69eebc0db 100644 (file)
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,14 @@
+2019-07-05  Szabolcs Nagy  <szabolcs.nagy@arm.com>
+
+       Backport from mainline
+       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.
+
 2019-07-05  Szabolcs Nagy  <szabolcs.nagy@arm.com>
 
        Backport from mainline

diff --git a/gas/config/tc-aarch64.c b/gas/config/tc-aarch64.c
index 12f4849be154777ac6d0b6937ff2ed927d795c7f..9cb7b7c722559452afd004d612983042de86863f 100644 (file)
--- a/gas/config/tc-aarch64.c
+++ b/gas/config/tc-aarch64.c
@@ -9345,3 +9345,35 @@ 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 50b76d30191339d792601a92928c5350f1c94db4..93d33713247da541cfb1b0bd8c57908f465883df 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