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, 30 insertions, 28 deletions

diff --git a/elf/dynamic-link.h b/elf/dynamic-link.h
index 3eb24ba3a6..7cc3021164 100644
--- a/elf/dynamic-link.h
+++ b/elf/dynamic-link.h
@@ -59,31 +59,33 @@ int _dl_try_allocate_static_tls (struct link_map *map, bool optional)
    copying memory, breaking the very code written to handle the
    unaligned cases.  */
 # if ! ELF_MACHINE_NO_REL
-auto inline void __attribute__((always_inline))
-elf_machine_rel (struct link_map *map, const ElfW(Rel) *reloc,
-		 const ElfW(Sym) *sym, const struct r_found_version *version,
+static inline void __attribute__((always_inline))
+elf_machine_rel (struct link_map *map, struct r_scope_elem *scope[],
+		 const ElfW(Rel) *reloc, const ElfW(Sym) *sym,
+		 const struct r_found_version *version,
 		 void *const reloc_addr, int skip_ifunc);
-auto inline void __attribute__((always_inline))
+static inline void __attribute__((always_inline))
 elf_machine_rel_relative (ElfW(Addr) l_addr, const ElfW(Rel) *reloc,
 			  void *const reloc_addr);
 # endif
 # if ! ELF_MACHINE_NO_RELA
-auto 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,
-		  void *const reloc_addr, int skip_ifunc);
-auto inline void __attribute__((always_inline))
+static inline void __attribute__((always_inline))
+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,
+		  int skip_ifunc);
+static inline void __attribute__((always_inline))
 elf_machine_rela_relative (ElfW(Addr) l_addr, const ElfW(Rela) *reloc,
 			   void *const reloc_addr);
 # endif
 # if ELF_MACHINE_NO_RELA || defined ELF_MACHINE_PLT_REL
-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[],
 		      ElfW(Addr) l_addr, const ElfW(Rel) *reloc,
 		      int skip_ifunc);
 # else
-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[],
 		      ElfW(Addr) l_addr, const ElfW(Rela) *reloc,
 		      int skip_ifunc);
 # endif
@@ -114,7 +116,7 @@ elf_machine_lazy_rel (struct link_map *map,
    consumes precisely the very end of the DT_REL*, or DT_JMPREL and DT_REL*
    are completely separate and there is a gap between them.  */
 
-# define _ELF_DYNAMIC_DO_RELOC(RELOC, reloc, map, do_lazy, skip_ifunc, test_rel) \
+# define _ELF_DYNAMIC_DO_RELOC(RELOC, reloc, map, scope, do_lazy, skip_ifunc, test_rel) \
   do {									      \
     struct { ElfW(Addr) start, size;					      \
 	     __typeof (((ElfW(Dyn) *) 0)->d_un.d_val) nrelative; int lazy; }  \
@@ -152,18 +154,18 @@ elf_machine_lazy_rel (struct link_map *map,
       }									      \
 									      \
     if (ELF_DURING_STARTUP)						      \
-      elf_dynamic_do_##reloc ((map), ranges[0].start, ranges[0].size,	      \
-			      ranges[0].nrelative, 0, skip_ifunc);	      \
+      elf_dynamic_do_##reloc ((map), scope, ranges[0].start, ranges[0].size,  \
+			      ranges[0].nrelative, 0, skip_ifunc);  \
     else								      \
       {									      \
 	int ranges_index;						      \
 	for (ranges_index = 0; ranges_index < 2; ++ranges_index)	      \
-	  elf_dynamic_do_##reloc ((map),				      \
+	  elf_dynamic_do_##reloc ((map), scope,				      \
 				  ranges[ranges_index].start,		      \
 				  ranges[ranges_index].size,		      \
 				  ranges[ranges_index].nrelative,	      \
 				  ranges[ranges_index].lazy,		      \
-				  skip_ifunc);				      \
+				  skip_ifunc);		      \
       }									      \
   } while (0)
 
@@ -175,29 +177,29 @@ elf_machine_lazy_rel (struct link_map *map,
 
 # if ! ELF_MACHINE_NO_REL
 #  include "do-rel.h"
-#  define ELF_DYNAMIC_DO_REL(map, lazy, skip_ifunc) \
-  _ELF_DYNAMIC_DO_RELOC (REL, Rel, map, lazy, skip_ifunc, _ELF_CHECK_REL)
+#  define ELF_DYNAMIC_DO_REL(map, scope, lazy, skip_ifunc)	      \
+  _ELF_DYNAMIC_DO_RELOC (REL, Rel, map, scope, lazy, skip_ifunc, _ELF_CHECK_REL)
 # else
-#  define ELF_DYNAMIC_DO_REL(map, lazy, skip_ifunc) /* Nothing to do.  */
+#  define ELF_DYNAMIC_DO_REL(map, scope, lazy, skip_ifunc) /* Nothing to do.  */
 # endif
 
 # if ! ELF_MACHINE_NO_RELA
 #  define DO_RELA
 #  include "do-rel.h"
-#  define ELF_DYNAMIC_DO_RELA(map, lazy, skip_ifunc) \
-  _ELF_DYNAMIC_DO_RELOC (RELA, Rela, map, lazy, skip_ifunc, _ELF_CHECK_REL)
+#  define ELF_DYNAMIC_DO_RELA(map, scope, lazy, skip_ifunc)	      \
+  _ELF_DYNAMIC_DO_RELOC (RELA, Rela, map, scope, lazy, skip_ifunc, _ELF_CHECK_REL)
 # else
-#  define ELF_DYNAMIC_DO_RELA(map, lazy, skip_ifunc) /* Nothing to do.  */
+#  define ELF_DYNAMIC_DO_RELA(map, scope, lazy, skip_ifunc) /* Nothing to do.  */
 # endif
 
 /* This can't just be an inline function because GCC is too dumb
    to inline functions containing inlines themselves.  */
-# define ELF_DYNAMIC_RELOCATE(map, lazy, consider_profile, skip_ifunc) \
+# define ELF_DYNAMIC_RELOCATE(map, scope, lazy, consider_profile, skip_ifunc) \
   do {									      \
-    int edr_lazy = elf_machine_runtime_setup ((map), (lazy),		      \
+    int edr_lazy = elf_machine_runtime_setup ((map), (scope), (lazy),	      \
 					      (consider_profile));	      \
-    ELF_DYNAMIC_DO_REL ((map), edr_lazy, skip_ifunc);			      \
-    ELF_DYNAMIC_DO_RELA ((map), edr_lazy, skip_ifunc);			      \
+    ELF_DYNAMIC_DO_REL ((map), (scope), edr_lazy, skip_ifunc);		      \
+    ELF_DYNAMIC_DO_RELA ((map), (scope), edr_lazy, skip_ifunc);		      \
   } while (0)
 
 #endif