From f2d4ba38f5723a207c40a288036af2f38b70e837 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Thu, 4 Jul 2019 10:35:47 +0200 Subject: gas/ELF: don't accumulate .type settings Recently a patch was submitted for a Xen Project test harness binary to override the compiler specified @object to @func (see [1]). In a reply I suggested we shouldn't make ourselves dependent on currently unspecified behavior of gas here: It accumulates all requests, and then bfd/elf.c:swap_out_syms(), in an apparently ad hoc manner, prioritizes certain flags over others. Make the behavior predictable: Generally the last .type is what counts. Exceptions are directives which set multiple bits (TLS, IFUNC, and UNIQUE): Subsequent directives requesting just the more generic bit (i.e. FUNC following IFUNC) won't clear the more specific one. Warn about incompatible changes, except from/to STT_NOTYPE. Also add a new target hook, which hppa wants to use right away afaict. In the course of adding the warning I ran into two ld testsuite failures. I can only assume that it was a copy-and-paste mistake that lead to the same symbol having its type set twice. [1] https://lists.xenproject.org/archives/html/xen-devel/2019-05/msg01980.html --- gas/config/obj-elf.c | 33 ++++++++++++++++++++++++++++++++- 1 file changed, 32 insertions(+), 1 deletion(-) (limited to 'gas/config/obj-elf.c') diff --git a/gas/config/obj-elf.c b/gas/config/obj-elf.c index 318e27d..224d4c2 100644 --- a/gas/config/obj-elf.c +++ b/gas/config/obj-elf.c @@ -2069,7 +2069,38 @@ obj_elf_type (int ignore ATTRIBUTE_UNUSED) if (*input_line_pointer == '"') ++input_line_pointer; - elfsym->symbol.flags |= type; +#ifdef md_elf_symbol_type_change + if (!md_elf_symbol_type_change (sym, elfsym, type)) +#endif + { + flagword mask = BSF_FUNCTION | BSF_OBJECT; + + if (type != BSF_FUNCTION) + mask |= BSF_GNU_INDIRECT_FUNCTION; + if (type != BSF_OBJECT) + { + mask |= BSF_GNU_UNIQUE | BSF_THREAD_LOCAL; + + if (S_IS_COMMON (sym)) + { + as_bad (_("cannot change type of common symbol '%s'"), + S_GET_NAME (sym)); + mask = type = 0; + } + } + + /* Don't warn when changing to STT_NOTYPE. */ + if (type) + { + flagword new = (elfsym->symbol.flags & ~mask) | type; + + if (new != (elfsym->symbol.flags | type)) + as_warn (_("symbol '%s' already has its type set"), S_GET_NAME (sym)); + elfsym->symbol.flags = new; + } + else + elfsym->symbol.flags &= ~mask; + } demand_empty_rest_of_line (); } -- cgit v1.1