[PATCH v2] target/mips: Rewrite UHI errno_mips() using switch statement

[Philippe Mathieu-Daudé]

Linking on Haiku OS fails:

  
/boot/system/develop/tools/bin/../lib/gcc/x86_64-unknown-haiku/8.3.0/../../../../x86_64-unknown-haiku/bin/ld:
  error: 
libqemu-mips-softmmu.fa.p/target_mips_tcg_sysemu_mips-semi.c.o(.rodata) is too 
large (0xffff405a bytes)
  
/boot/system/develop/tools/bin/../lib/gcc/x86_64-unknown-haiku/8.3.0/../../../../x86_64-unknown-haiku/bin/ld:
  final link failed: memory exhausted
  collect2: error: ld returned 1 exit status

This is because the host_to_mips_errno[] uses errno as index,
for example:

  static const uint16_t host_to_mips_errno[] = {
      [ENAMETOOLONG] = 91,
      ...

and Haiku defines [*] ENAMETOOLONG as:

   12 /* Error baselines */
   13 #define B_GENERAL_ERROR_BASE              INT_MIN
   ..
   22 #define B_STORAGE_ERROR_BASE              (B_GENERAL_ERROR_BASE + 0x6000)
  ...
  106 #define B_NAME_TOO_LONG                   (B_STORAGE_ERROR_BASE + 4)
  ...
  211 #define ENAMETOOLONG                      
B_TO_POSIX_ERROR(B_NAME_TOO_LONG)

so the array ends up beeing indeed too big.

Since POSIX errno can't be use as indexes on Haiku,
rewrite errno_mips() using a switch statement.

[*] https://github.com/haiku/haiku/blob/r1beta3/headers/os/support/Errors.h#L130

Reported-by: Richard Zak <richard.j.zak@gmail.com>
Suggested-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
Supersedes: <20210704170736.617895-4-f4bug@amsat.org>
---
 target/mips/tcg/sysemu/mips-semi.c | 24 +++++++++---------------
 1 file changed, 9 insertions(+), 15 deletions(-)

diff --git a/target/mips/tcg/sysemu/mips-semi.c 
b/target/mips/tcg/sysemu/mips-semi.c
index 77108b0b1a9..b4a383ae90c 100644
--- a/target/mips/tcg/sysemu/mips-semi.c
+++ b/target/mips/tcg/sysemu/mips-semi.c
@@ -74,25 +74,19 @@ enum UHIOpenFlags {
     UHIOpen_EXCL   = 0x800
 };
 
-/* Errno values taken from asm-mips/errno.h */
-static const uint16_t host_to_mips_errno[] = {
-    [ENAMETOOLONG] = 78,
+static int errno_mips(int host_errno)
+{
+    /* Errno values taken from asm-mips/errno.h */
+    switch (host_errno) {
+    case 0:             return 0;
+    case ENAMETOOLONG:  return 78;
 #ifdef EOVERFLOW
-    [EOVERFLOW]    = 79,
+    case EOVERFLOW:     return 79;
 #endif
 #ifdef ELOOP
-    [ELOOP]        = 90,
+    case ELOOP:         return 90;
 #endif
-};
-
-static int errno_mips(int err)
-{
-    if (err < 0 || err >= ARRAY_SIZE(host_to_mips_errno)) {
-        return EINVAL;
-    } else if (host_to_mips_errno[err]) {
-        return host_to_mips_errno[err];
-    } else {
-        return err;
+    default:            return EINVAL;
     }
 }
 
-- 
2.31.1