elf: Avoid nested functions in the loader (all ports) [BZ #27220]maskray/unnest

[Alternative to https://sourceware.org/pipermail/libc-alpha/2021-August/130340.html
This version fixes all ports and doesn't add NESTING dispatches.]
[Available at
https://sourceware.org/git/?p=glibc.git;a=shortlog;h=refs/heads/maskray/unnest ]

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 CC=clang (which doesn't support the
feature).

The key idea for unnesting is to add extra parameters (link_map * and
r_scope_elm *[]) to RESOLVE_MAP, ELF_MACHINE_BEFORE_RTLD_RELOC,
ELF_DYNAMIC_RELOCATE, elf_machine_rela?, 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 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-linux-gnu, powerpc64le-linux-gnu and x86_64-linux-gnu.

Tested build-many-glibcs.py glibcs with
{alpha,arc,csky,hppa,ia64,microblaze,nios2,s390x,sh4,sparc64,sparc64}-linux-gnu,
arm-linux-gnueabi, csky-linux-gnuabiv2, mips64-linux-gnu-n64, and riscv64-linux-gnu-rv64imafdc-lp64.

1 files changed, 9 insertions, 10 deletions

diff --git a/sysdeps/powerpc/powerpc32/dl-machine.h b/sysdeps/powerpc/powerpc32/dl-machine.h
index ced3a7b659..cda012dc1b 100644
--- a/sysdeps/powerpc/powerpc32/dl-machine.h
+++ b/sysdeps/powerpc/powerpc32/dl-machine.h
@@ -109,8 +109,6 @@ elf_machine_load_address (void)
   return runtime_dynamic - elf_machine_dynamic ();
 }
 
-#define ELF_MACHINE_BEFORE_RTLD_RELOC(dynamic_info) /* nothing */
-
 /* The PLT uses Elf32_Rela relocs.  */
 #define elf_machine_relplt elf_machine_rela
 
@@ -172,7 +170,7 @@ extern int __elf_machine_runtime_setup (struct link_map *map,
 					int lazy, int profile);
 
 static inline int
-elf_machine_runtime_setup (struct link_map *map,
+elf_machine_runtime_setup (struct link_map *map, struct r_scope_elem *scope[],
 			   int lazy, int profile)
 {
   if (map->l_info[DT_JMPREL] == 0)
@@ -286,9 +284,10 @@ extern void _dl_reloc_overflow (struct link_map *map,
    LOADADDR is the load address of the object; INFO is an array indexed
    by DT_* of the .dynamic section info.  */
 
-auto inline void __attribute__ ((always_inline))
-elf_machine_rela (struct link_map *map, const Elf32_Rela *reloc,
-		  const Elf32_Sym *sym, const struct r_found_version *version,
+static inline void __attribute__ ((always_inline))
+elf_machine_rela (struct link_map *map, struct r_scope_elem *scope[],
+		  const Elf32_Rela *reloc, const Elf32_Sym *sym,
+		  const struct r_found_version *version,
 		  void *const reloc_addr_arg, int skip_ifunc)
 {
   Elf32_Addr *const reloc_addr = reloc_addr_arg;
@@ -317,7 +316,7 @@ elf_machine_rela (struct link_map *map, const Elf32_Rela *reloc,
     }
   else
     {
-      sym_map = RESOLVE_MAP (&sym, version, r_type);
+      sym_map = RESOLVE_MAP (map, scope, &sym, version, r_type);
       value = SYMBOL_ADDRESS (sym_map, sym, true);
     }
   value += reloc->r_addend;
@@ -441,7 +440,7 @@ elf_machine_rela (struct link_map *map, const Elf32_Rela *reloc,
     }
 }
 
-auto inline void __attribute__ ((always_inline))
+static inline void __attribute__ ((always_inline))
 elf_machine_rela_relative (Elf32_Addr l_addr, const Elf32_Rela *reloc,
 			   void *const reloc_addr_arg)
 {
@@ -449,8 +448,8 @@ elf_machine_rela_relative (Elf32_Addr l_addr, const Elf32_Rela *reloc,
   *reloc_addr = l_addr + reloc->r_addend;
 }
 
-auto inline void __attribute__ ((always_inline))
-elf_machine_lazy_rel (struct link_map *map,
+static inline void __attribute__ ((always_inline))
+elf_machine_lazy_rel (struct link_map *map, struct r_scope_elem *scope[],
 		      Elf32_Addr l_addr, const Elf32_Rela *reloc,
 		      int skip_ifunc)
 {