elf: Avoid nested functions in the loader [BZ #27220]

dynamic-link.h is included more than once in some elf/ files (rtld.c,
dl-conflict.c, dl-reloc.c, dl-reloc-static-pie.c) and uses GCC nested
functions. This harms readability and the nested functions usage
is the biggest obstacle prevents Clang build (Clang doesn't support GCC
nested functions).

The key idea for unnesting is to add extra parameters (struct link_map
*and struct r_scope_elm *[]) to RESOLVE_MAP,
ELF_MACHINE_BEFORE_RTLD_RELOC, ELF_DYNAMIC_RELOCATE, elf_machine_rel[a],
elf_machine_lazy_rel, and elf_machine_runtime_setup. (This is inspired
by Stan Shebs' ppc64/x86-64 implementation in the
google/grte/v5-2.27/master which uses mixed extra parameters and static
variables.)

Future simplification:
* If mips elf_machine_runtime_setup no longer needs RESOLVE_GOTSYM,
  elf_machine_runtime_setup can drop the `scope` parameter.
* If TLSDESC no longer need to be in elf_machine_lazy_rel,
  elf_machine_lazy_rel can drop the `scope` parameter.

Tested on aarch64, i386, x86-64, powerpc64le, powerpc64, powerpc32,
sparc64, sparcv9, s390x, s390, hppa, ia64, armhf, alpha, and mips64.
In addition, tested build-many-glibcs.py with {arc,csky,microblaze,nios2}-linux-gnu
and riscv64-linux-gnu-rv64imafdc-lp64d.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

1 files changed, 13 insertions, 9 deletions

diff --git a/sysdeps/aarch64/dl-machine.h b/sysdeps/aarch64/dl-machine.h
index 3e10cb462f..e30e81c902 100644
--- a/sysdeps/aarch64/dl-machine.h
+++ b/sysdeps/aarch64/dl-machine.h
@@ -59,7 +59,8 @@ elf_machine_dynamic (void)
    entries will jump to the on-demand fixup code in dl-runtime.c.  */
 
 static inline int __attribute__ ((unused))
-elf_machine_runtime_setup (struct link_map *l, int lazy, int profile)
+elf_machine_runtime_setup (struct link_map *l, struct r_scope_elem *scope[],
+			   int lazy, int profile)
 {
   if (l->l_info[DT_JMPREL] && lazy)
     {
@@ -237,10 +238,11 @@ elf_machine_plt_value (struct link_map *map,
 
 #ifdef RESOLVE_MAP
 
-auto inline void
+static inline void
 __attribute__ ((always_inline))
-elf_machine_rela (struct link_map *map, const ElfW(Rela) *reloc,
-		  const ElfW(Sym) *sym, const struct r_found_version *version,
+elf_machine_rela (struct link_map *map, struct r_scope_elem *scope[],
+		  const ElfW(Rela) *reloc, const ElfW(Sym) *sym,
+		  const struct r_found_version *version,
 		  void *const reloc_addr_arg, int skip_ifunc)
 {
   ElfW(Addr) *const reloc_addr = reloc_addr_arg;
@@ -253,7 +255,8 @@ elf_machine_rela (struct link_map *map, const ElfW(Rela) *reloc,
   else
     {
       const ElfW(Sym) *const refsym = sym;
-      struct link_map *sym_map = RESOLVE_MAP (&sym, version, r_type);
+      struct link_map *sym_map = RESOLVE_MAP (map, scope, &sym, version,
+					      r_type);
       ElfW(Addr) value = SYMBOL_ADDRESS (sym_map, sym, true);
 
       if (sym != NULL
@@ -377,9 +380,9 @@ elf_machine_rela_relative (ElfW(Addr) l_addr,
   *reloc_addr = l_addr + reloc->r_addend;
 }
 
-inline void
+static inline void
 __attribute__ ((always_inline))
-elf_machine_lazy_rel (struct link_map *map,
+elf_machine_lazy_rel (struct link_map *map, struct r_scope_elem *scope[],
 		      ElfW(Addr) l_addr,
 		      const ElfW(Rela) *reloc,
 		      int skip_ifunc)
@@ -406,7 +409,7 @@ elf_machine_lazy_rel (struct link_map *map,
 		    (const void *)D_PTR (map, l_info[VERSYMIDX (DT_VERSYM)]);
 		  version = &map->l_versions[vernum[symndx] & 0x7fff];
 		}
-	      elf_machine_rela (map, reloc, sym, version, reloc_addr,
+	      elf_machine_rela (map, scope, reloc, sym, version, reloc_addr,
 				skip_ifunc);
 	      return;
 	    }
@@ -433,7 +436,8 @@ elf_machine_lazy_rel (struct link_map *map,
 
       /* Always initialize TLS descriptors completely, because lazy
 	 initialization requires synchronization at every TLS access.  */
-      elf_machine_rela (map, reloc, sym, version, reloc_addr, skip_ifunc);
+      elf_machine_rela (map, scope, reloc, sym, version, reloc_addr,
+			skip_ifunc);
     }
   else if (__glibc_unlikely (r_type == AARCH64_R(IRELATIVE)))
     {