diff --git a/libc/Android.bp b/libc/Android.bp
index 845945a..7b0ac23 100644
--- a/libc/Android.bp
+++ b/libc/Android.bp
@@ -1409,7 +1409,6 @@
         "bionic/mblen.cpp",
         "bionic/mbrtoc16.cpp",
         "bionic/mbrtoc32.cpp",
-        "bionic/mbstate.cpp",
         "bionic/memmem.cpp",
         "bionic/mempcpy.cpp",
         "bionic/mkdir.cpp",
diff --git a/libc/bionic/c16rtomb.cpp b/libc/bionic/c16rtomb.cpp
index 77512be..93749c6 100644
--- a/libc/bionic/c16rtomb.cpp
+++ b/libc/bionic/c16rtomb.cpp
@@ -50,18 +50,18 @@
       mbstate_set_byte(state, 2, (c32 & 0x00ff00) >> 8);
       return 0;
     } else if (is_low_surrogate(c16)) {
-      return reset_and_return_illegal(EINVAL, state);
+      return mbstate_reset_and_return_illegal(EINVAL, state);
     } else {
       return c32rtomb(s, static_cast<char32_t>(c16), state);
     }
   } else {
     if (!is_low_surrogate(c16)) {
-      return reset_and_return_illegal(EINVAL, state);
+      return mbstate_reset_and_return_illegal(EINVAL, state);
     }
 
     char32_t c32 = ((mbstate_get_byte(state, 3) << 16) |
                     (mbstate_get_byte(state, 2) << 8) |
                     (c16 & ~0xdc00)) + 0x10000;
-    return reset_and_return(c32rtomb(s, c32, NULL), state);
+    return mbstate_reset_and_return(c32rtomb(s, c32, NULL), state);
   }
 }
diff --git a/libc/bionic/c32rtomb.cpp b/libc/bionic/c32rtomb.cpp
index d3231c0..ebe9cd3 100644
--- a/libc/bionic/c32rtomb.cpp
+++ b/libc/bionic/c32rtomb.cpp
@@ -38,7 +38,7 @@
 
   if (s == NULL) {
     // Equivalent to c32rtomb(buf, U'\0', ps).
-    return reset_and_return(1, state);
+    return mbstate_reset_and_return(1, state);
   }
 
   // POSIX states that if char32_t is a null wide character, a null byte shall
@@ -47,11 +47,11 @@
   // stored.
   if (c32 == U'\0') {
     *s = '\0';
-    reset_and_return(1, state);
+    return mbstate_reset_and_return(1, state);
   }
 
   if (!mbsinit(state)) {
-    return reset_and_return_illegal(EILSEQ, state);
+    return mbstate_reset_and_return_illegal(EILSEQ, state);
   }
 
   if ((c32 & ~0x7f) == 0) {
diff --git a/libc/bionic/mbrtoc16.cpp b/libc/bionic/mbrtoc16.cpp
index 6878a11..2180516 100644
--- a/libc/bionic/mbrtoc16.cpp
+++ b/libc/bionic/mbrtoc16.cpp
@@ -55,7 +55,7 @@
   char16_t trail = mbstate_get_byte(state, 1) << 8 |
                    mbstate_get_byte(state, 0);
   *pc16 = trail;
-  return reset_and_return(mbstate_get_byte(state, 3), state);
+  return mbstate_reset_and_return(mbstate_get_byte(state, 3), state);
 }
 
 size_t mbrtoc16(char16_t* pc16, const char* s, size_t n, mbstate_t* ps) {
@@ -76,13 +76,13 @@
   if (__MB_IS_ERR(nconv)) {
     return nconv;
   } else if (nconv == 0) {
-    return reset_and_return(nconv, state);
+    return mbstate_reset_and_return(nconv, state);
   } else if (c32 > 0x10ffff) {
     // Input cannot be encoded as UTF-16.
-    return reset_and_return_illegal(EILSEQ, state);
+    return mbstate_reset_and_return_illegal(EILSEQ, state);
   } else if (c32 < 0x10000) {
     *pc16 = static_cast<char16_t>(c32);
-    return reset_and_return(nconv, state);
+    return mbstate_reset_and_return(nconv, state);
   } else {
     return begin_surrogate(c32, pc16, nconv, state);
   }
diff --git a/libc/bionic/mbrtoc32.cpp b/libc/bionic/mbrtoc32.cpp
index bd40ecf..f004b78 100644
--- a/libc/bionic/mbrtoc32.cpp
+++ b/libc/bionic/mbrtoc32.cpp
@@ -41,7 +41,7 @@
   // Full state verification is done when decoding the sequence (after we have
   // all the bytes).
   if (mbstate_get_byte(state, 3) != 0) {
-    return reset_and_return_illegal(EINVAL, state);
+    return mbstate_reset_and_return_illegal(EINVAL, state);
   }
 
   if (s == NULL) {
@@ -98,7 +98,7 @@
     lower_bound = 0x10000;
   } else {
     // Malformed input; input is not UTF-8. See RFC 3629.
-    return reset_and_return_illegal(EILSEQ, state);
+    return mbstate_reset_and_return_illegal(EILSEQ, state);
   }
 
   // Fill in the state.
@@ -107,7 +107,7 @@
   for (i = 0; i < MIN(bytes_wanted, n); i++) {
     if (!mbsinit(state) && ((*s & 0xc0) != 0x80)) {
       // Malformed input; bad characters in the middle of a character.
-      return reset_and_return_illegal(EILSEQ, state);
+      return mbstate_reset_and_return_illegal(EILSEQ, state);
     }
     mbstate_set_byte(state, bytes_so_far + i, *s++);
   }
@@ -125,14 +125,14 @@
 
   if (c32 < lower_bound) {
     // Malformed input; redundant encoding.
-    return reset_and_return_illegal(EILSEQ, state);
+    return mbstate_reset_and_return_illegal(EILSEQ, state);
   }
   if ((c32 >= 0xd800 && c32 <= 0xdfff) || c32 == 0xfffe || c32 == 0xffff) {
     // Malformed input; invalid code points.
-    return reset_and_return_illegal(EILSEQ, state);
+    return mbstate_reset_and_return_illegal(EILSEQ, state);
   }
   if (pc32 != NULL) {
     *pc32 = c32;
   }
-  return reset_and_return(c32 == U'\0' ? 0 : bytes_wanted, state);
+  return mbstate_reset_and_return(c32 == U'\0' ? 0 : bytes_wanted, state);
 }
diff --git a/libc/bionic/mbstate.cpp b/libc/bionic/mbstate.cpp
deleted file mode 100644
index cb327d8..0000000
--- a/libc/bionic/mbstate.cpp
+++ /dev/null
@@ -1,57 +0,0 @@
-/*
- * Copyright (C) 2014 The Android Open Source Project
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *  * Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- *  * Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in
- *    the documentation and/or other materials provided with the
- *    distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
- * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
- * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
- * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
- * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
- * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
- * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
-
-#include "private/bionic_mbstate.h"
-
-#include <errno.h>
-
-__LIBC_HIDDEN__ size_t mbstate_bytes_so_far(const mbstate_t* ps) {
-  return
-    (ps->__seq[2] != 0) ? 3 :
-    (ps->__seq[1] != 0) ? 2 :
-    (ps->__seq[0] != 0) ? 1 : 0;
-}
-
-__LIBC_HIDDEN__ void mbstate_set_byte(mbstate_t* ps, int i, char byte) {
-  ps->__seq[i] = static_cast<uint8_t>(byte);
-}
-
-__LIBC_HIDDEN__ uint8_t mbstate_get_byte(const mbstate_t* ps, int n) {
-  return ps->__seq[n];
-}
-
-__LIBC_HIDDEN__ size_t reset_and_return_illegal(int _errno, mbstate_t* ps) {
-  errno = _errno;
-  *(reinterpret_cast<uint32_t*>(ps->__seq)) = 0;
-  return __MB_ERR_ILLEGAL_SEQUENCE;
-}
-
-__LIBC_HIDDEN__ size_t reset_and_return(int _return, mbstate_t* ps) {
-  *(reinterpret_cast<uint32_t*>(ps->__seq)) = 0;
-  return _return;
-}
diff --git a/libc/bionic/wchar.cpp b/libc/bionic/wchar.cpp
index 36fc2a2..62023d6 100644
--- a/libc/bionic/wchar.cpp
+++ b/libc/bionic/wchar.cpp
@@ -74,7 +74,7 @@
   // character appears as anything but the first byte of a
   // multibyte sequence. Check now to avoid doing it in the loops.
   if (nmc > 0 && mbstate_bytes_so_far(state) > 0 && static_cast<uint8_t>((*src)[0]) < 0x80) {
-    return reset_and_return_illegal(EILSEQ, state);
+    return mbstate_reset_and_return_illegal(EILSEQ, state);
   }
 
   // Measure only?
@@ -83,23 +83,23 @@
       if (static_cast<uint8_t>((*src)[i]) < 0x80) {
         // Fast path for plain ASCII characters.
         if ((*src)[i] == '\0') {
-          return reset_and_return(o, state);
+          return mbstate_reset_and_return(o, state);
         }
         r = 1;
       } else {
         r = mbrtowc(NULL, *src + i, nmc - i, state);
         if (r == __MB_ERR_ILLEGAL_SEQUENCE) {
-          return reset_and_return_illegal(EILSEQ, state);
+          return mbstate_reset_and_return_illegal(EILSEQ, state);
         }
         if (r == __MB_ERR_INCOMPLETE_SEQUENCE) {
-          return reset_and_return_illegal(EILSEQ, state);
+          return mbstate_reset_and_return_illegal(EILSEQ, state);
         }
         if (r == 0) {
-          return reset_and_return(o, state);
+          return mbstate_reset_and_return(o, state);
         }
       }
     }
-    return reset_and_return(o, state);
+    return mbstate_reset_and_return(o, state);
   }
 
   // Actually convert, updating `dst` and `src`.
@@ -110,26 +110,26 @@
       r = 1;
       if ((*src)[i] == '\0') {
         *src = nullptr;
-        return reset_and_return(o, state);
+        return mbstate_reset_and_return(o, state);
       }
     } else {
       r = mbrtowc(dst + o, *src + i, nmc - i, state);
       if (r == __MB_ERR_ILLEGAL_SEQUENCE) {
         *src += i;
-        return reset_and_return_illegal(EILSEQ, state);
+        return mbstate_reset_and_return_illegal(EILSEQ, state);
       }
       if (r == __MB_ERR_INCOMPLETE_SEQUENCE) {
         *src += nmc;
-        return reset_and_return(EILSEQ, state);
+        return mbstate_reset_and_return_illegal(EILSEQ, state);
       }
       if (r == 0) {
         *src = NULL;
-        return reset_and_return(o, state);
+        return mbstate_reset_and_return(o, state);
       }
     }
   }
   *src += i;
-  return reset_and_return(o, state);
+  return mbstate_reset_and_return(o, state);
 }
 
 size_t mbsrtowcs(wchar_t* dst, const char** src, size_t len, mbstate_t* ps) {
@@ -149,7 +149,7 @@
   mbstate_t* state = (ps == NULL) ? &__private_state : ps;
 
   if (!mbsinit(state)) {
-    return reset_and_return_illegal(EILSEQ, state);
+    return mbstate_reset_and_return_illegal(EILSEQ, state);
   }
 
   char buf[MB_LEN_MAX];
diff --git a/libc/private/bionic_mbstate.h b/libc/private/bionic_mbstate.h
index 018b47c..292959a 100644
--- a/libc/private/bionic_mbstate.h
+++ b/libc/private/bionic_mbstate.h
@@ -43,11 +43,31 @@
 #define __MB_IS_ERR(rv) (rv == __MB_ERR_ILLEGAL_SEQUENCE || \
                          rv == __MB_ERR_INCOMPLETE_SEQUENCE)
 
-size_t mbstate_bytes_so_far(const mbstate_t* ps);
-void mbstate_set_byte(mbstate_t* ps, int i, char byte);
-uint8_t mbstate_get_byte(const mbstate_t* ps, int n);
-size_t reset_and_return_illegal(int _errno, mbstate_t* ps);
-size_t reset_and_return(int _return, mbstate_t* ps);
+static inline __wur size_t mbstate_bytes_so_far(const mbstate_t* ps) {
+  return
+      (ps->__seq[2] != 0) ? 3 :
+      (ps->__seq[1] != 0) ? 2 :
+      (ps->__seq[0] != 0) ? 1 : 0;
+}
+
+static inline void mbstate_set_byte(mbstate_t* ps, int i, char byte) {
+  ps->__seq[i] = static_cast<uint8_t>(byte);
+}
+
+static inline __wur uint8_t mbstate_get_byte(const mbstate_t* ps, int n) {
+  return ps->__seq[n];
+}
+
+static inline __wur size_t mbstate_reset_and_return_illegal(int _errno, mbstate_t* ps) {
+  errno = _errno;
+  *(reinterpret_cast<uint32_t*>(ps->__seq)) = 0;
+  return __MB_ERR_ILLEGAL_SEQUENCE;
+}
+
+static inline __wur size_t mbstate_reset_and_return(int _return, mbstate_t* ps) {
+  *(reinterpret_cast<uint32_t*>(ps->__seq)) = 0;
+  return _return;
+}
 
 __END_DECLS