[PATCH] modpost: refactor get_secindex()

From: Masahiro Yamada
Date: Tue Jul 26 2022 - 14:09:39 EST


SPECIAL() is only used in get_secindex(). Squash it.

Make the code more readable with more comments.

Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
---

scripts/mod/modpost.h | 30 ++++++++++++++++++------------
1 file changed, 18 insertions(+), 12 deletions(-)

diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
index bd874f906781..33b376d9ba71 100644
--- a/scripts/mod/modpost.h
+++ b/scripts/mod/modpost.h
@@ -156,22 +156,28 @@ static inline int is_shndx_special(unsigned int i)
return i != SHN_XINDEX && i >= SHN_LORESERVE && i <= SHN_HIRESERVE;
}

-/*
- * Move reserved section indices SHN_LORESERVE..SHN_HIRESERVE out of
- * the way to -256..-1, to avoid conflicting with real section
- * indices.
- */
-#define SPECIAL(i) ((i) - (SHN_HIRESERVE + 1))
-
/* Accessor for sym->st_shndx, hides ugliness of "64k sections" */
static inline unsigned int get_secindex(const struct elf_info *info,
const Elf_Sym *sym)
{
- if (is_shndx_special(sym->st_shndx))
- return SPECIAL(sym->st_shndx);
- if (sym->st_shndx != SHN_XINDEX)
- return sym->st_shndx;
- return info->symtab_shndx_start[sym - info->symtab_start];
+ unsigned int index = sym->st_shndx;
+
+ /*
+ * Elf{32,64}_Sym::st_shndx is 2 byte. Big section numbers are available
+ * in the .symtab_shndx section.
+ */
+ if (index == SHN_XINDEX)
+ return info->symtab_shndx_start[sym - info->symtab_start];
+
+ /*
+ * Move reserved section indices SHN_LORESERVE..SHN_HIRESERVE out of
+ * the way to UINT_MAX-255..UINT_MAX, to avoid conflicting with real
+ * section indices.
+ */
+ if (index >= SHN_LORESERVE)
+ return index - SHN_HIRESERVE - 1;
+
+ return index;
}

/* file2alias.c */
--
2.34.1