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>
(cherry picked from commit 490e6c62aa31a8aa5c4a059f6e646ede121edf0a)

28 files changed, 380 insertions, 323 deletions

diff --git a/elf/dl-conflict.c b/elf/dl-conflict.c
index 31a2f90770..5c8e51d19a 100644
--- a/elf/dl-conflict.c
+++ b/elf/dl-conflict.c
@@ -27,20 +27,12 @@
 #include <sys/types.h>
 #include "dynamic-link.h"
 
-void
-_dl_resolve_conflicts (struct link_map *l, ElfW(Rela) *conflict,
-		       ElfW(Rela) *conflictend)
-{
-#if ! ELF_MACHINE_NO_RELA
-  if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_RELOC))
-    _dl_debug_printf ("\nconflict processing: %s\n", DSO_FILENAME (l->l_name));
-
-  {
-    /* Do the conflict relocation of the object and library GOT and other
-       data.  */
+/* Used at loading time solely for prelink executable.  It is not called
+   concurrently so it is be safe to defined as static.  */
+static struct link_map *resolve_conflict_map __attribute__ ((__unused__));
 
     /* This macro is used as a callback from the ELF_DYNAMIC_RELOCATE code.  */
-#define RESOLVE_MAP(ref, version, flags) (*ref = NULL, NULL)
+#define RESOLVE_MAP(map, scope, ref, version, flags) (*ref = NULL, NULL)
 #define RESOLVE(ref, version, flags) (*ref = NULL, 0)
 #define RESOLVE_CONFLICT_FIND_MAP(map, r_offset) \
   do {									      \
@@ -51,12 +43,23 @@ _dl_resolve_conflicts (struct link_map *l, ElfW(Rela) *conflict,
     (map) = resolve_conflict_map;					      \
   } while (0)
 
+#include "dynamic-link.h"
+
+void
+_dl_resolve_conflicts (struct link_map *l, ElfW(Rela) *conflict,
+		       ElfW(Rela) *conflictend)
+{
+#if ! ELF_MACHINE_NO_RELA
+  if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_RELOC))
+    _dl_debug_printf ("\nconflict processing: %s\n", DSO_FILENAME (l->l_name));
+
+  {
+    /* Do the conflict relocation of the object and library GOT and other
+       data.  */
+
     /* Prelinking makes no sense for anything but the main namespace.  */
     assert (l->l_ns == LM_ID_BASE);
-    struct link_map *resolve_conflict_map __attribute__ ((__unused__))
-      = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
-
-#include "dynamic-link.h"
+    resolve_conflict_map = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
 
     /* Override these, defined in dynamic-link.h.  */
 #undef CHECK_STATIC_TLS
@@ -67,8 +70,8 @@ _dl_resolve_conflicts (struct link_map *l, ElfW(Rela) *conflict,
     GL(dl_num_cache_relocations) += conflictend - conflict;
 
     for (; conflict < conflictend; ++conflict)
-      elf_machine_rela (l, conflict, NULL, NULL, (void *) conflict->r_offset,
-			0);
+      elf_machine_rela (l, NULL, conflict, NULL, NULL,
+			(void *) conflict->r_offset, 0);
   }
 #endif
 }
diff --git a/elf/dl-reloc-static-pie.c b/elf/dl-reloc-static-pie.c
index 2fb02d7276..a52ba8aeb8 100644
--- a/elf/dl-reloc-static-pie.c
+++ b/elf/dl-reloc-static-pie.c
@@ -19,8 +19,14 @@
 #if ENABLE_STATIC_PIE
 /* Mark symbols hidden in static PIE for early self relocation to work.  */
 # pragma GCC visibility push(hidden)
+#include <assert.h>
 #include <unistd.h>
 #include <ldsodefs.h>
+
+#include <dl-machine.h>
+
+#define STATIC_PIE_BOOTSTRAP
+#define RESOLVE_MAP(map, scope, sym, version, flags) map
 #include "dynamic-link.h"
 
 /* Relocate static executable with PIE.  */
@@ -30,11 +36,6 @@ _dl_relocate_static_pie (void)
 {
   struct link_map *main_map = _dl_get_dl_main_map ();
 
-# define STATIC_PIE_BOOTSTRAP
-# define BOOTSTRAP_MAP (main_map)
-# define RESOLVE_MAP(sym, version, flags) BOOTSTRAP_MAP
-# include "dynamic-link.h"
-
   /* Figure out the run-time load address of static PIE.  */
   main_map->l_addr = elf_machine_load_address ();
 
@@ -53,12 +54,12 @@ _dl_relocate_static_pie (void)
   elf_get_dynamic_info (main_map);
 
 # ifdef ELF_MACHINE_BEFORE_RTLD_RELOC
-  ELF_MACHINE_BEFORE_RTLD_RELOC (main_map->l_info);
+  ELF_MACHINE_BEFORE_RTLD_RELOC (main_map, main_map->l_info);
 # endif
 
   /* Relocate ourselves so we can do normal function calls and
      data access using the global offset table.  */
-  ELF_DYNAMIC_RELOCATE (main_map, 0, 0, 0);
+  ELF_DYNAMIC_RELOCATE (main_map, NULL, 0, 0, 0);
   main_map->l_relocated = 1;
 
   /* Initialize _r_debug.  */
diff --git a/elf/dl-reloc.c b/elf/dl-reloc.c
index e13a672ade..3447de7f35 100644
--- a/elf/dl-reloc.c
+++ b/elf/dl-reloc.c
@@ -162,6 +162,32 @@ _dl_nothread_init_static_tls (struct link_map *map)
 }
 #endif /* !THREAD_GSCOPE_IN_TCB */
 
+/* This macro is used as a callback from the ELF_DYNAMIC_RELOCATE code.  */
+#define RESOLVE_MAP(l, scope, ref, version, r_type)			      \
+    ((ELFW(ST_BIND) ((*ref)->st_info) != STB_LOCAL			      \
+      && __glibc_likely (!dl_symbol_visibility_binds_local_p (*ref)))	      \
+     ? ((__glibc_unlikely ((*ref) == l->l_lookup_cache.sym)		      \
+	 && elf_machine_type_class (r_type) == l->l_lookup_cache.type_class)  \
+	? (bump_num_cache_relocations (),				      \
+	   (*ref) = l->l_lookup_cache.ret,				      \
+	   l->l_lookup_cache.value)					      \
+	: ({ lookup_t _lr;						      \
+	     int _tc = elf_machine_type_class (r_type);			      \
+	     l->l_lookup_cache.type_class = _tc;			      \
+	     l->l_lookup_cache.sym = (*ref);				      \
+	     const struct r_found_version *v = NULL;			      \
+	     if ((version) != NULL && (version)->hash != 0)		      \
+	       v = (version);						      \
+	     _lr = _dl_lookup_symbol_x ((const char *) D_PTR (l, l_info[DT_STRTAB]) + (*ref)->st_name, \
+					l, (ref), scope, v, _tc,	      \
+					DL_LOOKUP_ADD_DEPENDENCY	      \
+					| DL_LOOKUP_FOR_RELOCATE, NULL);      \
+	     l->l_lookup_cache.ret = (*ref);				      \
+	     l->l_lookup_cache.value = _lr; }))				      \
+     : l)
+
+#include "dynamic-link.h"
+
 void
 _dl_relocate_object (struct link_map *l, struct r_scope_elem *scope[],
 		     int reloc_mode, int consider_profiling)
@@ -243,36 +269,7 @@ _dl_relocate_object (struct link_map *l, struct r_scope_elem *scope[],
   {
     /* Do the actual relocation of the object's GOT and other data.  */
 
-    /* String table object symbols.  */
-    const char *strtab = (const void *) D_PTR (l, l_info[DT_STRTAB]);
-
-    /* This macro is used as a callback from the ELF_DYNAMIC_RELOCATE code.  */
-#define RESOLVE_MAP(ref, version, r_type) \
-    ((ELFW(ST_BIND) ((*ref)->st_info) != STB_LOCAL			      \
-      && __glibc_likely (!dl_symbol_visibility_binds_local_p (*ref)))	      \
-     ? ((__builtin_expect ((*ref) == l->l_lookup_cache.sym, 0)		      \
-	 && elf_machine_type_class (r_type) == l->l_lookup_cache.type_class)  \
-	? (bump_num_cache_relocations (),				      \
-	   (*ref) = l->l_lookup_cache.ret,				      \
-	   l->l_lookup_cache.value)					      \
-	: ({ lookup_t _lr;						      \
-	     int _tc = elf_machine_type_class (r_type);			      \
-	     l->l_lookup_cache.type_class = _tc;			      \
-	     l->l_lookup_cache.sym = (*ref);				      \
-	     const struct r_found_version *v = NULL;			      \
-	     if ((version) != NULL && (version)->hash != 0)		      \
-	       v = (version);						      \
-	     _lr = _dl_lookup_symbol_x (strtab + (*ref)->st_name, l, (ref),   \
-					scope, v, _tc,			      \
-					DL_LOOKUP_ADD_DEPENDENCY	      \
-					| DL_LOOKUP_FOR_RELOCATE, NULL);      \
-	     l->l_lookup_cache.ret = (*ref);				      \
-	     l->l_lookup_cache.value = _lr; }))				      \
-     : l)
-
-#include "dynamic-link.h"
-
-    ELF_DYNAMIC_RELOCATE (l, lazy, consider_profiling, skip_ifunc);
+    ELF_DYNAMIC_RELOCATE (l, scope, lazy, consider_profiling, skip_ifunc);
 
 #ifndef PROF
     if (__glibc_unlikely (consider_profiling)
diff --git a/elf/do-rel.h b/elf/do-rel.h
index 321ac2b359..f441b74919 100644
--- a/elf/do-rel.h
+++ b/elf/do-rel.h
@@ -37,8 +37,8 @@
    relocations; they should be set up to call _dl_runtime_resolve, rather
    than fully resolved now.  */
 
-auto inline void __attribute__ ((always_inline))
-elf_dynamic_do_Rel (struct link_map *map,
+static inline void __attribute__ ((always_inline))
+elf_dynamic_do_Rel (struct link_map *map, struct r_scope_elem *scope[],
 		    ElfW(Addr) reladdr, ElfW(Addr) relsize,
 		    __typeof (((ElfW(Dyn) *) 0)->d_un.d_val) nrelative,
 		    int lazy, int skip_ifunc)
@@ -68,13 +68,13 @@ elf_dynamic_do_Rel (struct link_map *map,
 	  }
 	else
 # endif
-	  elf_machine_lazy_rel (map, l_addr, r, skip_ifunc);
+	  elf_machine_lazy_rel (map, scope, l_addr, r, skip_ifunc);
 
 # ifdef ELF_MACHINE_IRELATIVE
       if (r2 != NULL)
 	for (; r2 <= end2; ++r2)
 	  if (ELFW(R_TYPE) (r2->r_info) == ELF_MACHINE_IRELATIVE)
-	    elf_machine_lazy_rel (map, l_addr, r2, skip_ifunc);
+	    elf_machine_lazy_rel (map, scope, l_addr, r2, skip_ifunc);
 # endif
     }
   else
@@ -134,7 +134,7 @@ elf_dynamic_do_Rel (struct link_map *map,
 #endif
 
 	      ElfW(Half) ndx = version[ELFW(R_SYM) (r->r_info)] & 0x7fff;
-	      elf_machine_rel (map, r, &symtab[ELFW(R_SYM) (r->r_info)],
+	      elf_machine_rel (map, scope, r, &symtab[ELFW(R_SYM) (r->r_info)],
 			       &map->l_versions[ndx],
 			       (void *) (l_addr + r->r_offset), skip_ifunc);
 	    }
@@ -146,7 +146,7 @@ elf_dynamic_do_Rel (struct link_map *map,
 		{
 		  ElfW(Half) ndx
 		    = version[ELFW(R_SYM) (r2->r_info)] & 0x7fff;
-		  elf_machine_rel (map, r2,
+		  elf_machine_rel (map, scope, r2,
 				   &symtab[ELFW(R_SYM) (r2->r_info)],
 				   &map->l_versions[ndx],
 				   (void *) (l_addr + r2->r_offset),
@@ -167,14 +167,14 @@ elf_dynamic_do_Rel (struct link_map *map,
 	      }
 	    else
 # endif
-	      elf_machine_rel (map, r, &symtab[ELFW(R_SYM) (r->r_info)], NULL,
+	      elf_machine_rel (map, scope, r, &symtab[ELFW(R_SYM) (r->r_info)], NULL,
 			       (void *) (l_addr + r->r_offset), skip_ifunc);
 
 # ifdef ELF_MACHINE_IRELATIVE
 	  if (r2 != NULL)
 	    for (; r2 <= end2; ++r2)
 	      if (ELFW(R_TYPE) (r2->r_info) == ELF_MACHINE_IRELATIVE)
-		elf_machine_rel (map, r2, &symtab[ELFW(R_SYM) (r2->r_info)],
+		elf_machine_rel (map, scope, r2, &symtab[ELFW(R_SYM) (r2->r_info)],
 				 NULL, (void *) (l_addr + r2->r_offset),
 				 skip_ifunc);
 # endif
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
diff --git a/elf/get-dynamic-info.h b/elf/get-dynamic-info.h
index 4aa2058abf..15c316b38c 100644
--- a/elf/get-dynamic-info.h
+++ b/elf/get-dynamic-info.h
@@ -16,18 +16,15 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
-/* This file is included multiple times and therefore lacks a header
-   file inclusion guard.  */