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, 31 insertions, 27 deletions

diff --git a/sysdeps/mips/dl-machine.h b/sysdeps/mips/dl-machine.h
index b74d427..f8d1298 100644
--- a/sysdeps/mips/dl-machine.h
+++ b/sysdeps/mips/dl-machine.h
@@ -187,9 +187,9 @@ elf_machine_load_address (void)
 
 /* We can't rely on elf_machine_got_rel because _dl_object_relocation_scope
    fiddles with global data.  */
-#define ELF_MACHINE_BEFORE_RTLD_RELOC(dynamic_info)			\
+#define ELF_MACHINE_BEFORE_RTLD_RELOC(bootstrap_map, dynamic_info)	\
 do {									\
-  struct link_map *map = BOOTSTRAP_MAP;					\
+  struct link_map *map = bootstrap_map;					\
   ElfW(Sym) *sym;							\
   ElfW(Addr) *got;							\
   int i, n;								\
@@ -474,11 +474,12 @@ elf_machine_plt_value (struct link_map *map, const ElfW(Rel) *reloc,
    by RELOC_ADDR.  SYM is the relocation symbol specified by R_INFO and
    MAP is the object containing the reloc.  */
 
-auto inline void
+static inline void
 __attribute__ ((always_inline))
-elf_machine_reloc (struct link_map *map, ElfW(Addr) r_info,
-		   const ElfW(Sym) *sym, const struct r_found_version *version,
-		   void *reloc_addr, ElfW(Addr) r_addend, int inplace_p)
+elf_machine_reloc (struct link_map *map, struct r_scope_elem *scope[],
+		   ElfW(Addr) r_info, const ElfW(Sym) *sym,
+		   const struct r_found_version *version, void *reloc_addr,
+		   ElfW(Addr) r_addend, int inplace_p)
 {
   const unsigned long int r_type = ELFW(R_TYPE) (r_info);
   ElfW(Addr) *addr_field = (ElfW(Addr) *) reloc_addr;
@@ -506,7 +507,8 @@ elf_machine_reloc (struct link_map *map, ElfW(Addr) r_info,
     case R_MIPS_TLS_TPREL32:
 # endif
       {
-	struct link_map *sym_map = RESOLVE_MAP (&sym, version, r_type);
+	struct link_map *sym_map = RESOLVE_MAP (map, scope, &sym, version,
+						r_type);
 
 	switch (r_type)
 	  {
@@ -646,7 +648,7 @@ elf_machine_reloc (struct link_map *map, ElfW(Addr) r_info,
 	  _dl_signal_error (0, map->l_name, NULL,
 			    "found jump slot relocation with non-zero addend");
 
-	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);
 	*addr_field = value;
 
@@ -660,7 +662,7 @@ elf_machine_reloc (struct link_map *map, ElfW(Addr) r_info,
 	ElfW(Addr) value;
 
 	/* Calculate the address of the symbol.  */
-	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);
 
 	if (__builtin_expect (sym == NULL, 0))
@@ -707,16 +709,17 @@ elf_machine_reloc (struct link_map *map, ElfW(Addr) r_info,
 /* Perform the relocation specified by RELOC and SYM (which is fully resolved).
    MAP is the object containing the reloc.  */
 
-auto inline void
+static 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,
-		 void *const reloc_addr, int skip_ifunc)
+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)
 {
-  elf_machine_reloc (map, reloc->r_info, sym, version, reloc_addr, 0, 1);
+  elf_machine_reloc (map, scope, reloc->r_info, sym, version, reloc_addr, 0, 1);
 }
 
-auto inline void
+static inline void
 __attribute__((always_inline))
 elf_machine_rel_relative (ElfW(Addr) l_addr, const ElfW(Rel) *reloc,
 			  void *const reloc_addr)
@@ -724,9 +727,9 @@ elf_machine_rel_relative (ElfW(Addr) l_addr, const ElfW(Rel) *reloc,
   /* XXX Nothing to do.  There is no relative relocation, right?  */
 }
 
-auto 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(Rel) *reloc,
 		      int skip_ifunc)
 {
@@ -747,17 +750,17 @@ elf_machine_lazy_rel (struct link_map *map,
     _dl_reloc_bad_type (map, r_type, 1);
 }
 
-auto inline void
+static inline void
 __attribute__ ((always_inline))
-elf_machine_rela (struct link_map *map, const ElfW(Rela) *reloc,
+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)
 {
-  elf_machine_reloc (map, reloc->r_info, sym, version, reloc_addr,
+  elf_machine_reloc (map, scope, reloc->r_info, sym, version, reloc_addr,
 		     reloc->r_addend, 0);
 }
 
-auto inline void
+static inline void
 __attribute__((always_inline))
 elf_machine_rela_relative (ElfW(Addr) l_addr, const ElfW(Rela) *reloc,
 			   void *const reloc_addr)
@@ -766,9 +769,9 @@ elf_machine_rela_relative (ElfW(Addr) l_addr, const ElfW(Rela) *reloc,
 
 #ifndef RTLD_BOOTSTRAP
 /* Relocate GOT. */
-auto inline void
+static inline void
 __attribute__((always_inline))
-elf_machine_got_rel (struct link_map *map, int lazy)
+elf_machine_got_rel (struct link_map *map, struct r_scope_elem *scope[], int lazy)
 {
   ElfW(Addr) *got;
   ElfW(Sym) *sym;
@@ -781,7 +784,7 @@ elf_machine_got_rel (struct link_map *map, int lazy)
       const struct r_found_version *version __attribute__ ((unused))	  \
 	= vernum ? &map->l_versions[vernum[sym_index] & 0x7fff] : NULL;	  \
       struct link_map *sym_map;						  \
-      sym_map = RESOLVE_MAP (&ref, version, reloc);			  \
+      sym_map = RESOLVE_MAP (map, scope, &ref, version, reloc);		  \
       SYMBOL_ADDRESS (sym_map, ref, true);				  \
     })
 
@@ -867,9 +870,10 @@ elf_machine_got_rel (struct link_map *map, int lazy)
 /* Set up the loaded object described by L so its stub function
    will jump to the on-demand fixup code __dl_runtime_resolve.  */
 
-auto inline int
+static inline int
 __attribute__((always_inline))
-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)
 {
 # ifndef RTLD_BOOTSTRAP
   ElfW(Addr) *got;
@@ -899,7 +903,7 @@ elf_machine_runtime_setup (struct link_map *l, int lazy, int profile)
     }
 
   /* Relocate global offset table.  */
-  elf_machine_got_rel (l, lazy);
+  elf_machine_got_rel (l, scope, lazy);
 
   /* If using PLTs, fill in the first two entries of .got.plt.  */
   if (l->l_info[DT_JMPREL] && lazy)