bsd-user: elfload: simplify bswap a bit.

Reduce the number of ifdefs by always calling the swapping routine, but
making them empty when swapping isn't needed.

Signed-off-by: Warner Losh <imp@bsdimp.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

bsd-user/elfload.c

@@ -88,20 +88,27 @@ static void bswap_ehdr(struct elfhdr *ehdr)
     bswap16s(&ehdr->e_shstrndx);        /* Section header string table index */
 }
 
-static void bswap_phdr(struct elf_phdr *phdr)
+static void bswap_phdr(struct elf_phdr *phdr, int phnum)
 {
+    int i;
+
+    for (i = 0; i < phnum; i++, phdr++) {
         bswap32s(&phdr->p_type);        /* Segment type */
+        bswap32s(&phdr->p_flags);       /* Segment flags */
         bswaptls(&phdr->p_offset);      /* Segment file offset */
         bswaptls(&phdr->p_vaddr);       /* Segment virtual address */
         bswaptls(&phdr->p_paddr);       /* Segment physical address */
         bswaptls(&phdr->p_filesz);      /* Segment size in file */
         bswaptls(&phdr->p_memsz);       /* Segment size in memory */
-    bswap32s(&phdr->p_flags);           /* Segment flags */
         bswaptls(&phdr->p_align);       /* Segment alignment */
     }
+}
 
-static void bswap_shdr(struct elf_shdr *shdr)
+static void bswap_shdr(struct elf_shdr *shdr, int shnum)
 {
+    int i;
+
+    for (i = 0; i < shnum; i++, shdr++) {
         bswap32s(&shdr->sh_name);
         bswap32s(&shdr->sh_type);
         bswaptls(&shdr->sh_flags);
@@ -113,6 +120,7 @@ static void bswap_shdr(struct elf_shdr *shdr)
         bswaptls(&shdr->sh_addralign);
         bswaptls(&shdr->sh_entsize);
     }
+}
 
 static void bswap_sym(struct elf_sym *sym)
 {
@@ -121,7 +129,15 @@ static void bswap_sym(struct elf_sym *sym)
     bswaptls(&sym->st_size);
     bswap16s(&sym->st_shndx);
 }
-#endif
+
+#else /* ! BSWAP_NEEDED */
+
+static void bswap_ehdr(struct elfhdr *ehdr) { }
+static void bswap_phdr(struct elf_phdr *phdr, int phnum) { }
+static void bswap_shdr(struct elf_shdr *shdr, int shnum) { }
+static void bswap_sym(struct elf_sym *sym) { }
+
+#endif /* ! BSWAP_NEEDED */
 
 /*
  * 'copy_elf_strings()' copies argument/envelope strings from user
@@ -367,9 +383,7 @@ static abi_ulong load_elf_interp(struct elfhdr *interp_elf_ex,
     last_bss = 0;
     error = 0;
 
-#ifdef BSWAP_NEEDED
     bswap_ehdr(interp_elf_ex);
-#endif
     /* First of all, some simple consistency checks */
     if ((interp_elf_ex->e_type != ET_EXEC &&
          interp_elf_ex->e_type != ET_DYN) ||
@@ -410,12 +424,7 @@ static abi_ulong load_elf_interp(struct elfhdr *interp_elf_ex,
         free(elf_phdata);
         return retval;
     }
-#ifdef BSWAP_NEEDED
+    bswap_phdr(elf_phdata, interp_elf_ex->e_phnum);
-    eppnt = elf_phdata;
-    for (i = 0; i<interp_elf_ex->e_phnum; i++, eppnt++) {
-        bswap_phdr(eppnt);
-    }
-#endif
 
     if (interp_elf_ex->e_type == ET_DYN) {
         /* in order to avoid hardcoding the interpreter load
@@ -560,9 +569,7 @@ static void load_symbols(struct elfhdr *hdr, int fd)
     for (i = 0; i < hdr->e_shnum; i++) {
         if (read(fd, &sechdr, sizeof(sechdr)) != sizeof(sechdr))
             return;
-#ifdef BSWAP_NEEDED
+        bswap_shdr(&sechdr, 1);
-        bswap_shdr(&sechdr);
-#endif
         if (sechdr.sh_type == SHT_SYMTAB) {
             symtab = sechdr;
             lseek(fd, hdr->e_shoff
@@ -570,9 +577,7 @@ static void load_symbols(struct elfhdr *hdr, int fd)
             if (read(fd, &strtab, sizeof(strtab))
                 != sizeof(strtab))
                 return;
-#ifdef BSWAP_NEEDED
+            bswap_shdr(&strtab, 1);
-            bswap_shdr(&strtab);
-#endif
             goto found;
         }
     }
@@ -605,9 +610,7 @@ static void load_symbols(struct elfhdr *hdr, int fd)
 
     i = 0;
     while (i < nsyms) {
-#ifdef BSWAP_NEEDED
         bswap_sym(syms + i);
-#endif
         // Throw away entries which we do not need.
         if (syms[i].st_shndx == SHN_UNDEF ||
                 syms[i].st_shndx >= SHN_LORESERVE ||
@@ -679,9 +682,7 @@ int load_elf_binary(struct bsd_binprm *bprm, struct target_pt_regs *regs,
     load_addr = 0;
     load_bias = 0;
     elf_ex = *((struct elfhdr *) bprm->buf);          /* exec-header */
-#ifdef BSWAP_NEEDED
     bswap_ehdr(&elf_ex);
-#endif
 
     /* First of all, some simple consistency checks */
     if ((elf_ex.e_type != ET_EXEC && elf_ex.e_type != ET_DYN) ||
@@ -715,12 +716,8 @@ int load_elf_binary(struct bsd_binprm *bprm, struct target_pt_regs *regs,
         return -errno;
     }
 
-#ifdef BSWAP_NEEDED
+    bswap_phdr(elf_phdata, elf_ex.e_phnum);
-    elf_ppnt = elf_phdata;
+
-    for (i = 0; i < elf_ex.e_phnum; i++, elf_ppnt++) {
-        bswap_phdr(elf_ppnt);
-    }
-#endif
     elf_ppnt = elf_phdata;
 
     elf_bss = 0;