Prefer inline functions in character.h

In character.h, replace macros with inline functions or enums
when this is easy.  This improves maintainability and
on my platform (Fedora 31 x86-64, gcc -O2) improved CPU
performance very slightly (0.3%) on ‘make compile-always’.
* src/buffer.h (SANE_TAB_WIDTH, CHARACTER_WIDTH):
Move here from character.h, and make them inline functions.
Tune CHARACTER_WIDTH so that ASCII_CHAR_WIDTH is no longer needed.
(sanitize_tab_width, sanitize_char_width):
Move here from character.h.
* src/character.h (MAX_CHAR, MAX_UNICODE_CHAR, MAX_1_BYTE_CHAR)
(MAX_2_BYTE_CHAR, MAX_3_BYTE_CHAR, MAX_4_BYTE_CHAR)
(MAX_5_BYTE_CHAR, MIN_MULTIBYTE_LEADING_CODE)
(MAX_MULTIBYTE_LEADING_CODE, MAX_MULTIBYTE_LENGTH):
Now enum constants instead of macros.
* src/character.h (CHAR_BYTES): Redo to avoid conditional branches.
(CHAR_BYTE8_P, BYTE8_TO_CHAR, UNIBYTE_TO_CHAR, CHAR_TO_BYTE8)
(CHAR_TO_BYTE_SAFE, CHAR_BYTE8_HEAD_P, CHARACTERP)
(CHECK_CHARACTER, CHECK_CHARACTER_CAR, CHECK_CHARACTER_CDR)
(CHAR_PRINTABLE_P, CHAR_BYTES, CHAR_LEADING_CODE, BYTE8_STRING)
(LEADING_CODE_P, TRAILING_CODE_P, CHAR_HEAD_P)
(BYTES_BY_CHAR_HEAD):
Now inline functions instead of macros.
(ASCII_CHAR_WIDTH): Remove; no longer used.
* src/conf_post.h (ATTRIBUTE_PURE): New macro.
* src/lisp.h (char_table_ref): Use it, for better inlining.
* src/fns.c (base64_decode_1): Add now-necessary casts.

5 files changed, 224 insertions, 161 deletions

diff --git a/src/buffer.h b/src/buffer.h
index abb1294d038..9875b8a447b 100644
--- a/src/buffer.h
+++ b/src/buffer.h
@@ -1523,6 +1523,45 @@ lowercasep (int c)
   return !uppercasep (c) && upcase (c) != c;
 }
 
+/* Return a non-outlandish value for the tab width.  */
+
+INLINE int
+sanitize_tab_width (Lisp_Object width)
+{
+  return (FIXNUMP (width) && 0 < XFIXNUM (width) && XFIXNUM (width) <= 1000
+	  ? XFIXNUM (width) : 8);
+}
+
+INLINE int
+SANE_TAB_WIDTH (struct buffer *buf)
+{
+  return sanitize_tab_width (BVAR (buf, tab_width));
+}
+
+/* Return a non-outlandish value for a character width.  */
+
+INLINE int
+sanitize_char_width (EMACS_INT width)
+{
+  return 0 <= width && width <= 1000 ? width : 1000;
+}
+
+/* Return the width of character C.  The width is measured by how many
+   columns C will occupy on the screen when displayed in the current
+   buffer.  The name CHARACTER_WIDTH avoids a collision with <limits.h>
+   CHAR_WIDTH.  */
+
+INLINE int
+CHARACTER_WIDTH (int c)
+{
+  return (0x20 <= c && c < 0x7f ? 1
+	  : 0x7f < c ? (sanitize_char_width
+			(XFIXNUM (CHAR_TABLE_REF (Vchar_width_table, c))))
+	  : c == '\t' ? SANE_TAB_WIDTH (current_buffer)
+	  : c == '\n' ? 0
+	  : !NILP (BVAR (current_buffer, ctl_arrow)) ? 2 : 4);
+}
+
 INLINE_HEADER_END
 
 #endif /* EMACS_BUFFER_H */
diff --git a/src/character.h b/src/character.h
index 7639b018cb0..d4bc718af72 100644
--- a/src/character.h
+++ b/src/character.h
@@ -43,23 +43,23 @@ INLINE_HEADER_BEGIN
 */
 
 /* Maximum character code ((1 << CHARACTERBITS) - 1).  */
-#define MAX_CHAR  0x3FFFFF
+enum { MAX_CHAR = 0x3FFFFF };
 
 /* Maximum Unicode character code.  */
-#define MAX_UNICODE_CHAR 0x10FFFF
+enum { MAX_UNICODE_CHAR = 0x10FFFF };
 
 /* Maximum N-byte character codes.  */
-#define MAX_1_BYTE_CHAR 0x7F
-#define MAX_2_BYTE_CHAR 0x7FF
-#define MAX_3_BYTE_CHAR 0xFFFF
-#define MAX_4_BYTE_CHAR 0x1FFFFF
-#define MAX_5_BYTE_CHAR 0x3FFF7F
+enum { MAX_1_BYTE_CHAR = 0x7F };
+enum { MAX_2_BYTE_CHAR = 0x7FF };
+enum { MAX_3_BYTE_CHAR = 0xFFFF };
+enum { MAX_4_BYTE_CHAR = 0x1FFFFF };
+enum { MAX_5_BYTE_CHAR = 0x3FFF7F };
 
 /* Minimum leading code of multibyte characters.  */
-#define MIN_MULTIBYTE_LEADING_CODE 0xC0
+enum { MIN_MULTIBYTE_LEADING_CODE = 0xC0 };
 /* Maximum leading code of multibyte characters.  Note: this must be
    updated if we ever increase MAX_CHAR above.  */
-#define MAX_MULTIBYTE_LEADING_CODE 0xF8
+enum { MAX_MULTIBYTE_LEADING_CODE = 0xF8 };
 
 /* Unicode character values.  */
 enum
@@ -81,33 +81,57 @@ enum
 };
 
 extern int char_string (unsigned, unsigned char *);
+extern int string_char (const unsigned char *,
+                        const unsigned char **, int *);
 
 /* UTF-8 encodings.  Use \x escapes, so they are portable to pre-C11
    compilers and can be concatenated with ordinary string literals.  */
 #define uLSQM "\xE2\x80\x98" /* U+2018 LEFT SINGLE QUOTATION MARK */
 #define uRSQM "\xE2\x80\x99" /* U+2019 RIGHT SINGLE QUOTATION MARK */
 
-/* Nonzero iff C is a character that corresponds to a raw 8-bit
+/* True iff C is a character that corresponds to a raw 8-bit
    byte.  */
-#define CHAR_BYTE8_P(c) ((c) > MAX_5_BYTE_CHAR)
+INLINE bool
+CHAR_BYTE8_P (int c)
+{
+  return MAX_5_BYTE_CHAR < c;
+}
 
 /* Return the character code for raw 8-bit byte BYTE.  */
-#define BYTE8_TO_CHAR(byte) ((byte) + 0x3FFF00)
+INLINE int
+BYTE8_TO_CHAR (int byte)
+{
+  return byte + 0x3FFF00;
+}
 
-#define UNIBYTE_TO_CHAR(byte) \
-  (ASCII_CHAR_P (byte) ? (byte) : BYTE8_TO_CHAR (byte))
+INLINE int
+UNIBYTE_TO_CHAR (int byte)
+{
+  return ASCII_CHAR_P (byte) ? byte : BYTE8_TO_CHAR (byte);
+}
 
 /* Return the raw 8-bit byte for character C.  */
-#define CHAR_TO_BYTE8(c) (CHAR_BYTE8_P (c) ? (c) - 0x3FFF00 : (c & 0xFF))
+INLINE int
+CHAR_TO_BYTE8 (int c)
+{
+  return CHAR_BYTE8_P (c) ? c - 0x3FFF00 : c & 0xFF;
+}
 
 /* Return the raw 8-bit byte for character C,
    or -1 if C doesn't correspond to a byte.  */
-#define CHAR_TO_BYTE_SAFE(c)						\
-  (ASCII_CHAR_P (c) ? c : (CHAR_BYTE8_P (c) ? (c) - 0x3FFF00 : -1))
+INLINE int
+CHAR_TO_BYTE_SAFE (int c)
+{
+  return ASCII_CHAR_P (c) ? c : CHAR_BYTE8_P (c) ? c - 0x3FFF00 : -1;
+}
 
-/* Nonzero iff BYTE is the 1st byte of a multibyte form of a character
+/* True iff BYTE is the 1st byte of a multibyte form of a character
    that corresponds to a raw 8-bit byte.  */
-#define CHAR_BYTE8_HEAD_P(byte) ((byte) == 0xC0 || (byte) == 0xC1)
+INLINE bool
+CHAR_BYTE8_HEAD_P (int byte)
+{
+  return byte == 0xC0 || byte == 0xC1;
+}
 
 /* If C is not ASCII, make it unibyte. */
 #define MAKE_CHAR_UNIBYTE(c)	\
@@ -122,10 +146,7 @@ extern int char_string (unsigned, unsigned char *);
   (eassert ((c) >= 0 && (c) < 256), (c) = UNIBYTE_TO_CHAR (c))
 
 /* This is the maximum byte length of multibyte form.  */
-#define MAX_MULTIBYTE_LENGTH 5
-
-/* Nonzero iff X is a character.  */
-#define CHARACTERP(x) (FIXNATP (x) && XFIXNAT (x) <= MAX_CHAR)
+enum { MAX_MULTIBYTE_LENGTH = 5 };
 
 /* Nonzero iff C is valid as a character code.  */
 INLINE bool
@@ -134,52 +155,69 @@ CHAR_VALID_P (intmax_t c)
   return 0 <= c && c <= MAX_CHAR;
 }
 
+/* Nonzero iff X is a character.  */
+INLINE bool
+CHARACTERP (Lisp_Object x)
+{
+  return FIXNUMP (x) && CHAR_VALID_P (XFIXNUM (x));
+}
+
 /* Check if Lisp object X is a character or not.  */
-#define CHECK_CHARACTER(x) \
-  CHECK_TYPE (CHARACTERP (x), Qcharacterp, x)
+INLINE void
+CHECK_CHARACTER (Lisp_Object x)
+{
+  CHECK_TYPE (CHARACTERP (x), Qcharacterp, x);
+}
 
-#define CHECK_CHARACTER_CAR(x) \
-  do {					\
-    Lisp_Object tmp = XCAR (x);		\
-    CHECK_CHARACTER (tmp);		\
-  } while (false)
+INLINE void
+CHECK_CHARACTER_CAR (Lisp_Object x)
+{
+  CHECK_CHARACTER (XCAR (x));
+}
 
-#define CHECK_CHARACTER_CDR(x) \
-  do {					\
-    Lisp_Object tmp = XCDR (x);		\
-    CHECK_CHARACTER (tmp);		\
-  } while (false)
+INLINE void
+CHECK_CHARACTER_CDR (Lisp_Object x)
+{
+  CHECK_CHARACTER (XCDR (x));
+}
 
-/* Nonzero iff C is a character of code less than 0x100.  */
+/* True iff C is a character of code less than 0x100.  */
 INLINE bool
 SINGLE_BYTE_CHAR_P (intmax_t c)
 {
   return 0 <= c && c < 0x100;
 }
 
-/* Nonzero if character C has a printable glyph.  */
-#define CHAR_PRINTABLE_P(c)	\
-  (((c) >= 32 && (c) < 127)	\
-   || ! NILP (CHAR_TABLE_REF (Vprintable_chars, (c))))
+/* True if character C has a printable glyph.  */
+INLINE bool
+CHAR_PRINTABLE_P (int c)
+{
+  return ((32 <= c && c < 127)
+	  || ! NILP (CHAR_TABLE_REF (Vprintable_chars, c)));
+}
 
 /* Return byte length of multibyte form for character C.  */
-#define CHAR_BYTES(c)			\
-  ( (c) <= MAX_1_BYTE_CHAR ? 1		\
-    : (c) <= MAX_2_BYTE_CHAR ? 2	\
-    : (c) <= MAX_3_BYTE_CHAR ? 3	\
-    : (c) <= MAX_4_BYTE_CHAR ? 4	\
-    : (c) <= MAX_5_BYTE_CHAR ? 5	\
-    : 2)
-
+INLINE int
+CHAR_BYTES (int c)
+{
+  return ((MAX_5_BYTE_CHAR < c ? -2 : 1)
+	  + (MAX_1_BYTE_CHAR < c)
+	  + (MAX_2_BYTE_CHAR < c)
+	  + (MAX_3_BYTE_CHAR < c)
+	  + (MAX_4_BYTE_CHAR < c));
+}
 
 /* Return the leading code of multibyte form of C.  */
-#define CHAR_LEADING_CODE(c)				\
-  ((c) <= MAX_1_BYTE_CHAR ? c				\
-   : (c) <= MAX_2_BYTE_CHAR ? (0xC0 | ((c) >> 6))	\
-   : (c) <= MAX_3_BYTE_CHAR ? (0xE0 | ((c) >> 12))	\
-   : (c) <= MAX_4_BYTE_CHAR ? (0xF0 | ((c) >> 18))	\
-   : (c) <= MAX_5_BYTE_CHAR ? 0xF8			\
-   : (0xC0 | (((c) >> 6) & 0x01)))
+INLINE int
+CHAR_LEADING_CODE (int c)
+{
+  return (c <= MAX_1_BYTE_CHAR ? c
+	  : c <= MAX_2_BYTE_CHAR ? 0xC0 | (c >> 6)
+	  : c <= MAX_3_BYTE_CHAR ? 0xE0 | (c >> 12)
+	  : c <= MAX_4_BYTE_CHAR ? 0xF0 | (c >> 18)
+	  : c <= MAX_5_BYTE_CHAR ? 0xF8
+	  : 0xC0 | ((c >> 6) & 0x01));
+}
 
 
 /* Store multibyte form of the character C in P.  The caller should
@@ -217,10 +255,13 @@ CHAR_STRING (int c, unsigned char *p)
    least MAX_MULTIBYTE_LENGTH bytes area at P in advance.  Returns the
    length of the multibyte form.  */
 
-#define BYTE8_STRING(b, p)			\
-  ((p)[0] = (0xC0 | (((b) >> 6) & 0x01)),	\
-   (p)[1] = (0x80 | ((b) & 0x3F)),		\
-   2)
+INLINE int
+BYTE8_STRING (int b, unsigned char *p)
+{
+  p[0] = 0xC0 | ((b >> 6) & 0x01);
+  p[1] = 0x80 | (b & 0x3F);
+  return 2;
+}
 
 
 /* Store multibyte form of the character C in P and advance P to the
@@ -246,28 +287,42 @@ CHAR_STRING (int c, unsigned char *p)
   } while (false)
 
 
-/* Nonzero iff BYTE starts a non-ASCII character in a multibyte
-   form.  */
-#define LEADING_CODE_P(byte) (((byte) & 0xC0) == 0xC0)
+/* True iff BYTE starts a non-ASCII character in a multibyte form.  */
+INLINE bool
+LEADING_CODE_P (int byte)
+{
+  return (byte & 0xC0) == 0xC0;
+}
 
-/* Nonzero iff BYTE is a trailing code of a non-ASCII character in a
+/* True iff BYTE is a trailing code of a non-ASCII character in a
    multibyte form.  */
-#define TRAILING_CODE_P(byte) (((byte) & 0xC0) == 0x80)
+INLINE bool
+TRAILING_CODE_P (int byte)
+{
+  return (byte & 0xC0) == 0x80;
+}
 
-/* Nonzero iff BYTE starts a character in a multibyte form.
+/* True iff BYTE starts a character in a multibyte form.
    This is equivalent to:
 	(ASCII_CHAR_P (byte) || LEADING_CODE_P (byte))  */
-#define CHAR_HEAD_P(byte) (((byte) & 0xC0) != 0x80)
+INLINE bool
+CHAR_HEAD_P (int byte)
+{
+  return (byte & 0xC0) != 0x80;
+}
 
 /* How many bytes a character that starts with BYTE occupies in a
-   multibyte form.  Unlike MULTIBYTE_LENGTH below, this macro does not
+   multibyte form.  Unlike MULTIBYTE_LENGTH below, this function does not
    validate the multibyte form, but looks only at its first byte.  */
-#define BYTES_BY_CHAR_HEAD(byte)	\
-  (!((byte) & 0x80) ? 1			\
-   : !((byte) & 0x20) ? 2		\
-   : !((byte) & 0x10) ? 3		\
-   : !((byte) & 0x08) ? 4		\
-   : 5)
+INLINE int
+BYTES_BY_CHAR_HEAD (int byte)
+{
+  return (!(byte & 0x80) ? 1
+	  : !(byte & 0x20) ? 2
+	  : !(byte & 0x10) ? 3
+	  : !(byte & 0x08) ? 4
+	  : 5);
+}
 
 
 /* The byte length of multibyte form at unibyte string P ending at
@@ -275,34 +330,40 @@ CHAR_STRING (int c, unsigned char *p)
    return 0.  Unlike BYTES_BY_CHAR_HEAD, this macro validates the
    multibyte form.  */
 
-#define MULTIBYTE_LENGTH(p, pend)				\
-  (p >= pend ? 0						\
-   : !((p)[0] & 0x80) ? 1					\
-   : ((p + 1 >= pend) || (((p)[1] & 0xC0) != 0x80)) ? 0		\
-   : ((p)[0] & 0xE0) == 0xC0 ? 2				\
-   : ((p + 2 >= pend) || (((p)[2] & 0xC0) != 0x80)) ? 0		\
-   : ((p)[0] & 0xF0) == 0xE0 ? 3				\
-   : ((p + 3 >= pend) || (((p)[3] & 0xC0) != 0x80)) ? 0		\
-   : ((p)[0] & 0xF8) == 0xF0 ? 4				\
-   : ((p + 4 >= pend) || (((p)[4] & 0xC0) != 0x80)) ? 0		\
-   : (p)[0] == 0xF8 && ((p)[1] & 0xF0) == 0x80 ? 5		\
-   : 0)
+INLINE int
+MULTIBYTE_LENGTH (unsigned char const *p, unsigned char const *pend)
+{
+  return (! (p < pend) ? 0
+	  : ! (p[0] & 0x80) ? 1
+	  : ! (p + 1 < pend && (p[1] & 0xC0) == 0x80) ? 0
+	  : (p[0] & 0xE0) == 0xC0 ? 2
+	  : ! (p + 2 < pend && (p[2] & 0xC0) == 0x80) ? 0
+	  : (p[0] & 0xF0) == 0xE0 ? 3
+	  : ! (p + 3 < pend && (p[3] & 0xC0) == 0x80) ? 0
+	  : (p[0] & 0xF8) == 0xF0 ? 4
+	  : ! (p + 4 < pend && (p[4] & 0xC0) == 0x80) ? 0
+	  : p[0] == 0xF8 && (p[1] & 0xF0) == 0x80 ? 5
+	  : 0);
+}
 
 
 /* Like MULTIBYTE_LENGTH, but don't check the ending address.  The
    multibyte form is still validated, unlike BYTES_BY_CHAR_HEAD.  */
 
-#define MULTIBYTE_LENGTH_NO_CHECK(p)			\
-  (!((p)[0] & 0x80) ? 1					\
-   : ((p)[1] & 0xC0) != 0x80 ? 0			\
-   : ((p)[0] & 0xE0) == 0xC0 ? 2			\
-   : ((p)[2] & 0xC0) != 0x80 ? 0			\
-   : ((p)[0] & 0xF0) == 0xE0 ? 3			\
-   : ((p)[3] & 0xC0) != 0x80 ? 0			\
-   : ((p)[0] & 0xF8) == 0xF0 ? 4			\
-   : ((p)[4] & 0xC0) != 0x80 ? 0			\
-   : (p)[0] == 0xF8 && ((p)[1] & 0xF0) == 0x80 ? 5	\
-   : 0)
+INLINE int
+MULTIBYTE_LENGTH_NO_CHECK (unsigned char const *p)
+{
+  return (!(p[0] & 0x80) ? 1
+	  : (p[1] & 0xC0) != 0x80 ? 0
+	  : (p[0] & 0xE0) == 0xC0 ? 2
+	  : (p[2] & 0xC0) != 0x80 ? 0
+	  : (p[0] & 0xF0) == 0xE0 ? 3
+	  : (p[3] & 0xC0) != 0x80 ? 0
+	  : (p[0] & 0xF8) == 0xF0 ? 4
+	  : (p[4] & 0xC0) != 0x80 ? 0
+	  : p[0] == 0xF8 && (p[1] & 0xF0) == 0x80 ? 5
+	  : 0);
+}
 
 /* If P is before LIMIT, advance P to the next character boundary.
    Assumes that P is already at a character boundary of the same
@@ -333,18 +394,21 @@ CHAR_STRING (int c, unsigned char *p)
 
 /* Return the character code of character whose multibyte form is at P.  */
 
-#define STRING_CHAR(p)						\
-  (!((p)[0] & 0x80)						\
-   ? (p)[0]							\
-   : ! ((p)[0] & 0x20)						\
-   ? (((((p)[0] & 0x1F) << 6)					\
-       | ((p)[1] & 0x3F))					\
-      + (((unsigned char) (p)[0]) < 0xC2 ? 0x3FFF80 : 0))	\
-   : ! ((p)[0] & 0x10)						\
-   ? ((((p)[0] & 0x0F) << 12)					\
-      | (((p)[1] & 0x3F) << 6)					\
-      | ((p)[2] & 0x3F))					\
-   : string_char ((p), NULL, NULL))
+INLINE int
+STRING_CHAR (unsigned char const *p)
+{
+  return (!(p[0] & 0x80)
+	  ? p[0]
+	  : ! (p[0] & 0x20)
+	  ? ((((p[0] & 0x1F) << 6)
+	      | (p[1] & 0x3F))
+	     + (p[0] < 0xC2 ? 0x3FFF80 : 0))
+	  : ! (p[0] & 0x10)
+	  ? (((p[0] & 0x0F) << 12)
+	     | ((p[1] & 0x3F) << 6)
+	     | (p[2] & 0x3F))
+	  : string_char (p, NULL, NULL));
+}
 
 
 /* Like STRING_CHAR, but set ACTUAL_LEN to the length of multibyte
@@ -578,58 +642,19 @@ CHAR_STRING (int c, unsigned char *p)
   } while (false)
 
 
-/* Return a non-outlandish value for the tab width.  */
-
-#define SANE_TAB_WIDTH(buf) sanitize_tab_width (BVAR (buf, tab_width))
-
-INLINE int
-sanitize_tab_width (Lisp_Object width)
-{
-  return (FIXNUMP (width) && 0 < XFIXNUM (width) && XFIXNUM (width) <= 1000
-	  ? XFIXNUM (width) : 8);
-}
-
-/* Return the width of ASCII character C.  The width is measured by
-   how many columns C will occupy on the screen when displayed in the
-   current buffer.  */
-
-#define ASCII_CHAR_WIDTH(c)						\
-  (c < 0x20								\
-   ? (c == '\t'								\
-      ? SANE_TAB_WIDTH (current_buffer)					\
-      : (c == '\n' ? 0 : (NILP (BVAR (current_buffer, ctl_arrow)) ? 4 : 2)))	\
-   : (c < 0x7f								\
-      ? 1								\
-      : ((NILP (BVAR (current_buffer, ctl_arrow)) ? 4 : 2))))
-
-/* Return a non-outlandish value for a character width.  */
+/* If C is a variation selector, return the index of the
+   variation selector (1..256).  Otherwise, return 0.  */
 
 INLINE int
-sanitize_char_width (EMACS_INT width)
+CHAR_VARIATION_SELECTOR_P (int c)
 {
-  return 0 <= width && width <= 1000 ? width : 1000;
+  return (c < 0xFE00 ? 0
+	  : c <= 0xFE0F ? c - 0xFE00 + 1
+	  : c < 0xE0100 ? 0
+	  : c <= 0xE01EF ? c - 0xE0100 + 17
+	  : 0);
 }
 
-/* Return the width of character C.  The width is measured by how many
-   columns C will occupy on the screen when displayed in the current
-   buffer.  The name CHARACTER_WIDTH avoids a collision with <limits.h>
-   CHAR_WIDTH when enabled; see ISO/IEC TS 18661-1:2014.  */
-
-#define CHARACTER_WIDTH(c)	\
-  (ASCII_CHAR_P (c)		\
-   ? ASCII_CHAR_WIDTH (c)	\
-   : sanitize_char_width (XFIXNUM (CHAR_TABLE_REF (Vchar_width_table, c))))
-
-/* If C is a variation selector, return the index of the
-   variation selector (1..256).  Otherwise, return 0.  */
-
-#define CHAR_VARIATION_SELECTOR_P(c)		\
-  ((c) < 0xFE00 ? 0				\
-   : (c) <= 0xFE0F ? (c) - 0xFE00 + 1		\
-   : (c) < 0xE0100 ? 0				\
-   : (c) <= 0xE01EF ? (c) - 0xE0100 + 17	\
-   : 0)
-
 /* Return true if C is a surrogate.  */
 
 INLINE bool
@@ -679,8 +704,6 @@ typedef enum {
 } unicode_category_t;
 
 extern EMACS_INT char_resolve_modifier_mask (EMACS_INT) ATTRIBUTE_CONST;
-extern int string_char (const unsigned char *,
-                        const unsigned char **, int *);
 
 extern int translate_char (Lisp_Object, int c);
 extern ptrdiff_t count_size_as_multibyte (const unsigned char *, ptrdiff_t);
diff --git a/src/conf_post.h b/src/conf_post.h
index 79fb4cfe8a7..8a6b32998d8 100644
--- a/src/conf_post.h
+++ b/src/conf_post.h
@@ -290,6 +290,7 @@ extern int emacs_setenv_TZ (char const *);
 
 #define ARG_NONNULL _GL_ARG_NONNULL
 #define ATTRIBUTE_CONST _GL_ATTRIBUTE_CONST
+#define ATTRIBUTE_PURE _GL_ATTRIBUTE_PURE
 #define ATTRIBUTE_UNUSED _GL_UNUSED
 
 #if GNUC_PREREQ (3, 3, 0) && !defined __ICC
diff --git a/src/fns.c b/src/fns.c
index 138082e07c8..e22fbaaedb9 100644
--- a/src/fns.c
+++ b/src/fns.c
@@ -3700,7 +3700,7 @@ base64_decode_1 (const char *from, char *to, ptrdiff_t length,
 
       c = value >> 16 & 0xff;
       if (c & multibyte_bit)
-	e += BYTE8_STRING (c, e);
+	e += BYTE8_STRING (c, (unsigned char *) e);
       else
 	*e++ = c;
       nchars++;
@@ -3742,7 +3742,7 @@ base64_decode_1 (const char *from, char *to, ptrdiff_t length,
 
       c = value >> 8 & 0xff;
       if (c & multibyte_bit)
-	e += BYTE8_STRING (c, e);
+	e += BYTE8_STRING (c, (unsigned char *) e);
       else
 	*e++ = c;
       nchars++;
@@ -3772,7 +3772,7 @@ base64_decode_1 (const char *from, char *to, ptrdiff_t length,
 
       c = value & 0xff;
       if (c & multibyte_bit)
-	e += BYTE8_STRING (c, e);
+	e += BYTE8_STRING (c, (unsigned char *) e);
       else
 	*e++ = c;
       nchars++;
diff --git a/src/lisp.h b/src/lisp.h
index 706ca6b9a82..b4ac017dcf5 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -597,7 +597,7 @@ extern Lisp_Object make_biguint (uintmax_t);
 extern uintmax_t check_uinteger_max (Lisp_Object, uintmax_t);
 
 /* Defined in chartab.c.  */
-extern Lisp_Object char_table_ref (Lisp_Object, int);
+extern Lisp_Object char_table_ref (Lisp_Object, int) ATTRIBUTE_PURE;
 extern void char_table_set (Lisp_Object, int, Lisp_Object);
 
 /* Defined in data.c.  */