[PATCH] ldso - adding HAVE_RELATIVE_RELOCS define - updated

[olsajiri at gmail.com]

Hi,
I moved the HAVE_RELATIVE_RELOCS to the dl-sysdep.h.
Also found there were warnings of non used variables due to the
ifdef'ed block. The rest is the same.


As the former comment suggested, I added the HAVE_RELATIVE_RELOCS and
and reduced the linker code size.

 [Nr] Name              Type            Addr     Off    Size   ES Flg Lk Inf Al
-[ 6] .text             PROGBITS        00000a2c 000a2c 00323e 00  AX  0   0  4
+[ 6] .text             PROGBITS        00000a2c 000a2c 003133 00  AX  0   0  4

I suppose most of the linkers support -Bsymbolic,
but I could verify only i386 and arm. 

Signed-off-by: Jiri Olsa <olsajiri at gmail.com>
---
Index: ldso/ldso/arm/dl-sysdep.h
===================================================================
--- ldso/ldso/arm/dl-sysdep.h	(revision 24692)
+++ ldso/ldso/arm/dl-sysdep.h	(working copy)
@@ -52,6 +52,9 @@
 /* Used for error messages */
 #define ELF_TARGET "ARM"
 
+/* The linker supports relative relocations */
+#define HAVE_RELATIVE_RELOCS
+
 struct elf_resolve;
 unsigned long _dl_linux_resolver(struct elf_resolve * tpnt, int reloc_entry);
 
Index: ldso/ldso/dl-startup.c
===================================================================
--- ldso/ldso/dl-startup.c	(revision 24692)
+++ ldso/ldso/dl-startup.c	(working copy)
@@ -233,12 +233,6 @@
 # define INDX_MAX 2
 #endif
 		for (indx = 0; indx < INDX_MAX; indx++) {
-			unsigned int i;
-			unsigned long *reloc_addr;
-			unsigned long symbol_addr;
-			int symtab_index;
-			ElfW(Sym) *sym;
-			ELF_RELOC *rpnt;
 			unsigned long rel_addr, rel_size;
 			ElfW(Word) relative_count = tpnt->dynamic_info[DT_RELCONT_IDX];
 
@@ -250,41 +244,52 @@
 			if (!rel_addr)
 				continue;
 
-			/* Now parse the relocation information */
-			/* Since ldso is linked with -Bsymbolic, all relocs will be RELATIVE(for those archs that have
-			   RELATIVE relocs) which means that the for(..) loop below has nothing to do and can be deleted.
-			   Possibly one should add a HAVE_RELATIVE_RELOCS directive and #ifdef away some code. */
 			if (!indx && relative_count) {
 				rel_size -= relative_count * sizeof(ELF_RELOC);
 				elf_machine_relative(load_addr, rel_addr, relative_count);
 				rel_addr += relative_count * sizeof(ELF_RELOC);
 			}
 
-			rpnt = (ELF_RELOC *) rel_addr;
-			for (i = 0; i < rel_size; i += sizeof(ELF_RELOC), rpnt++) {
-				reloc_addr = (unsigned long *) DL_RELOC_ADDR(load_addr, (unsigned long)rpnt->r_offset);
-				symtab_index = ELF_R_SYM(rpnt->r_info);
-				symbol_addr = 0;
-				sym = NULL;
-				if (symtab_index) {
-					char *strtab;
-					ElfW(Sym) *symtab;
+			/* Since ldso is linked with -Bsymbolic, all relocs will be RELATIVE (for those archs that have
+			   RELATIVE relocs - HAVE_RELATIVE_RELOCS define).  Which means that the for(..) loop below has 
+			   nothing to do and can omited. */
+#if !defined(HAVE_RELATIVE_RELOCS)
+			{
+				ELF_RELOC *rpnt;
+				unsigned int i;
+				ElfW(Sym) *sym;
+				unsigned long symbol_addr;
+				int symtab_index;
+				unsigned long *reloc_addr;
+				
+				/* Now parse the relocation information */
+				rpnt = (ELF_RELOC *) rel_addr;
+				for (i = 0; i < rel_size; i += sizeof(ELF_RELOC), rpnt++) {
+					reloc_addr = (unsigned long *) DL_RELOC_ADDR(load_addr, (unsigned long)rpnt->r_offset);
+					symtab_index = ELF_R_SYM(rpnt->r_info);
+					symbol_addr = 0;
+					sym = NULL;
+					if (symtab_index) {
+						char *strtab;
+						ElfW(Sym) *symtab;
 
-					symtab = (ElfW(Sym) *) tpnt->dynamic_info[DT_SYMTAB];
-					strtab = (char *) tpnt->dynamic_info[DT_STRTAB];
-					sym = &symtab[symtab_index];
-					symbol_addr = (unsigned long) DL_RELOC_ADDR(load_addr, sym->st_value);
+						symtab = (ElfW(Sym) *) tpnt->dynamic_info[DT_SYMTAB];
+						strtab = (char *) tpnt->dynamic_info[DT_STRTAB];
+						sym = &symtab[symtab_index];
+						symbol_addr = (unsigned long) DL_RELOC_ADDR(load_addr, sym->st_value);
 #if !defined(EARLY_STDERR_SPECIAL)
-					SEND_STDERR_DEBUG("relocating symbol: ");
-					SEND_STDERR_DEBUG(strtab + sym->st_name);
-					SEND_STDERR_DEBUG("\n");
+						SEND_STDERR_DEBUG("relocating symbol: ");
+						SEND_STDERR_DEBUG(strtab + sym->st_name);
+						SEND_STDERR_DEBUG("\n");
 #endif
-				} else {
-					SEND_STDERR_DEBUG("relocating unknown symbol\n");
+					} else {
+						SEND_STDERR_DEBUG("relocating unknown symbol\n");
+					}
+					/* Use this machine-specific macro to perform the actual relocation.  */
+					PERFORM_BOOTSTRAP_RELOC(rpnt, reloc_addr, symbol_addr, load_addr, sym);
 				}
-				/* Use this machine-specific macro to perform the actual relocation.  */
-				PERFORM_BOOTSTRAP_RELOC(rpnt, reloc_addr, symbol_addr, load_addr, sym);
 			}
+#endif // !defined(HAVE_RELATIVE_RELOCS)
 		}
 	}
 #endif
Index: ldso/ldso/i386/dl-sysdep.h
===================================================================
--- ldso/ldso/i386/dl-sysdep.h	(revision 24692)
+++ ldso/ldso/i386/dl-sysdep.h	(working copy)
@@ -22,6 +22,9 @@
 /* Used for error messages */
 #define ELF_TARGET "386"
 
+/* The linker supports relative relocations */
+#define HAVE_RELATIVE_RELOCS
+
 struct elf_resolve;
 extern unsigned long _dl_linux_resolver(struct elf_resolve * tpnt, int reloc_entry);