c - gcc を使用した c99 インラインセマンティクス (mspgcc)

Question

インライン化したい関数をいくつか書いています。

ここを読んで、次のように、すべての宣言と定義に対してインラインで 2 番目の c99 インラインオプションを使用します。

extern inline void SPFD54124B_write_cmd(uint16_t command);

ヘッダーで、および

inline void SPFD54124B_write_cmd(uint16_t command)
{
    spi_write(command, CMD_WIDTH);
}

対応する c ファイルで。関数のインラインバージョンを取得することを期待していました。

しかし、コンパイルすると次のようになります。

Generating dependencies dep/spi.d from src/spi.c
Generating dependencies dep/spfd54124b.d from src/spfd54124b.c
Generating dependencies dep/pomodoro.d from src/pomodoro.c
Generating dependencies dep/font8x8_ualnum.d from src/font8x8_ualnum.c
Generating dependencies dep/font8x8_basic.d from src/font8x8_basic.c
Generating dependencies dep/evading_util.d from src/evading_util.c
Compiling src/evading_util.c
Compiling src/font8x8_basic.c
Compiling src/font8x8_ualnum.c
Compiling src/pomodoro.c
src/spfd54124b.h:96:20: warning: inline function 'SPFD54124B_write_pixel' declared but never defined [enabled by default]
src/spfd54124b.h:95:20: warning: inline function 'SPFD54124B_write_param' declared but never defined [enabled by default]
src/spfd54124b.h:94:20: warning: inline function 'SPFD54124B_write_cmd' declared but never defined [enabled by default]
src/spi.h:22:20: warning: inline function 'spi_write' declared but never defined [enabled by default]
src/spfd54124b.h:96:20: warning: inline function 'SPFD54124B_write_pixel' declared but never defined [enabled by default]
src/spfd54124b.h:95:20: warning: inline function 'SPFD54124B_write_param' declared but never defined [enabled by default]
src/spfd54124b.h:94:20: warning: inline function 'SPFD54124B_write_cmd' declared but never defined [enabled by default]
src/spi.h:22:20: warning: inline function 'spi_write' declared but never defined [enabled by default]
src/pomodoro.c: In function 'main':
src/spfd54124b.h:94:20: warning: inlining failed in call to 'SPFD54124B_write_cmd': function body not available [-Winline]
src/pomodoro.c:29:25: warning: called from here [-Winline]
src/spfd54124b.h:94:20: warning: inlining failed in call to 'SPFD54124B_write_cmd': function body not available [-Winline]
src/pomodoro.c:31:25: warning: called from here [-Winline]
src/spfd54124b.h:94:20: warning: inlining failed in call to 'SPFD54124B_write_cmd': function body not available [-Winline]
src/pomodoro.c:35:25: warning: called from here [-Winline]
src/spfd54124b.h:94:20: warning: inlining failed in call to 'SPFD54124B_write_cmd': function body not available [-Winline]
src/pomodoro.c:36:25: warning: called from here [-Winline]
src/spfd54124b.h:96:20: warning: inlining failed in call to 'SPFD54124B_write_pixel': function body not available [-Winline]
src/pomodoro.c:40:31: warning: called from here [-Winline]
src/spfd54124b.h:94:20: warning: inlining failed in call to 'SPFD54124B_write_cmd': function body not available [-Winline]
src/pomodoro.c:43:25: warning: called from here [-Winline]
Compiling src/spfd54124b.c
src/spi.h:22:20: warning: inline function 'spi_write' declared but never defined [enabled by default]
src/spi.h:22:20: warning: inline function 'spi_write' declared but never defined [enabled by default]
src/spfd54124b.c: In function 'SPFD54124B_init':
src/spi.h:22:20: warning: inlining failed in call to 'spi_write': function body not available [-Winline]
src/spfd54124b.c:124:14: warning: called from here [-Winline]
src/spi.h:22:20: warning: inlining failed in call to 'spi_write': function body not available [-Winline]
src/spfd54124b.c:129:14: warning: called from here [-Winline]
src/spi.h:22:20: warning: inlining failed in call to 'spi_write': function body not available [-Winline]
src/spfd54124b.c:124:14: warning: called from here [-Winline]
src/spi.h:22:20: warning: inlining failed in call to 'spi_write': function body not available [-Winline]
src/spfd54124b.c:129:14: warning: called from here [-Winline]
src/spfd54124b.c: In function 'SPFD54124B_read':
src/spi.h:22:20: warning: inlining failed in call to 'spi_write': function body not available [-Winline]
src/spfd54124b.c:25:14: warning: called from here [-Winline]
src/spi.h:22:20: warning: inlining failed in call to 'spi_write': function body not available [-Winline]
src/spfd54124b.c:29:14: warning: called from here [-Winline]
src/spfd54124b.c: In function 'SPFD54124B_write_cmd':
src/spi.h:22:20: warning: inlining failed in call to 'spi_write': function body not available [-Winline]
src/spfd54124b.c:124:14: warning: called from here [-Winline]
src/spfd54124b.c: In function 'SPFD54124B_write_param':
src/spi.h:22:20: warning: inlining failed in call to 'spi_write': function body not available [-Winline]
src/spfd54124b.c:129:14: warning: called from here [-Winline]
src/spfd54124b.c: In function 'SPFD54124B_write_pixel':
src/spi.h:22:20: warning: inlining failed in call to 'spi_write': function body not available [-Winline]
src/spfd54124b.c:129:14: warning: called from here [-Winline]
src/spi.h:22:20: warning: inlining failed in call to 'spi_write': function body not available [-Winline]
src/spfd54124b.c:129:14: warning: called from here [-Winline]
src/spfd54124b.c: In function 'SPFD54124B_setrow':
src/spi.h:22:20: warning: inlining failed in call to 'spi_write': function body not available [-Winline]
src/spfd54124b.c:124:14: warning: called from here [-Winline]
src/spi.h:22:20: warning: inlining failed in call to 'spi_write': function body not available [-Winline]
src/spfd54124b.c:129:14: warning: called from here [-Winline]
src/spi.h:22:20: warning: inlining failed in call to 'spi_write': function body not available [-Winline]
src/spfd54124b.c:129:14: warning: called from here [-Winline]
src/spi.h:22:20: warning: inlining failed in call to 'spi_write': function body not available [-Winline]
src/spfd54124b.c:129:14: warning: called from here [-Winline]
src/spi.h:22:20: warning: inlining failed in call to 'spi_write': function body not available [-Winline]
src/spfd54124b.c:129:14: warning: called from here [-Winline]
src/spfd54124b.c: In function 'SPFD54124B_setcol':
src/spi.h:22:20: warning: inlining failed in call to 'spi_write': function body not available [-Winline]
src/spfd54124b.c:124:14: warning: called from here [-Winline]
src/spi.h:22:20: warning: inlining failed in call to 'spi_write': function body not available [-Winline]
src/spfd54124b.c:129:14: warning: called from here [-Winline]
src/spi.h:22:20: warning: inlining failed in call to 'spi_write': function body not available [-Winline]
src/spfd54124b.c:129:14: warning: called from here [-Winline]
src/spi.h:22:20: warning: inlining failed in call to 'spi_write': function body not available [-Winline]
src/spfd54124b.c:129:14: warning: called from here [-Winline]
src/spi.h:22:20: warning: inlining failed in call to 'spi_write': function body not available [-Winline]
src/spfd54124b.c:129:14: warning: called from here [-Winline]
src/spfd54124b.c: In function 'SPFD54124B_lputch':
src/spi.h:22:20: warning: inlining failed in call to 'spi_write': function body not available [-Winline]
src/spfd54124b.c:124:14: warning: called from here [-Winline]
src/spi.h:22:20: warning: inlining failed in call to 'spi_write': function body not available [-Winline]
src/spfd54124b.c:129:14: warning: called from here [-Winline]
src/spi.h:22:20: warning: inlining failed in call to 'spi_write': function body not available [-Winline]
src/spfd54124b.c:129:14: warning: called from here [-Winline]
src/spi.h:22:20: warning: inlining failed in call to 'spi_write': function body not available [-Winline]
src/spfd54124b.c:129:14: warning: called from here [-Winline]
src/spi.h:22:20: warning: inlining failed in call to 'spi_write': function body not available [-Winline]
src/spfd54124b.c:129:14: warning: called from here [-Winline]
src/spfd54124b.c: In function 'SPFD54124B_putch':
src/spi.h:22:20: warning: inlining failed in call to 'spi_write': function body not available [-Winline]
src/spfd54124b.c:124:14: warning: called from here [-Winline]
src/spi.h:22:20: warning: inlining failed in call to 'spi_write': function body not available [-Winline]
src/spfd54124b.c:129:14: warning: called from here [-Winline]
src/spi.h:22:20: warning: inlining failed in call to 'spi_write': function body not available [-Winline]
src/spfd54124b.c:129:14: warning: called from here [-Winline]
src/spi.h:22:20: warning: inlining failed in call to 'spi_write': function body not available [-Winline]
src/spfd54124b.c:129:14: warning: called from here [-Winline]
src/spi.h:22:20: warning: inlining failed in call to 'spi_write': function body not available [-Winline]
src/spfd54124b.c:129:14: warning: called from here [-Winline]
Compiling src/spi.c
Linking bin/pomodoro.elf

>>>> Size of Firmware <<<<
   text    data     bss     dec     hex filename
   3150       0       2    3152     c50 bin/pomodoro.elf

src/spfd54124b.h:96:20: warning: inline function 'SPFD54124B_write_pixel' declared but never defined [enabled by default]
src/spfd54124b.h:95:20: warning: inline function 'SPFD54124B_write_param' declared but never defined [enabled by default]
src/spfd54124b.h:94:20: warning: inline function 'SPFD54124B_write_cmd' declared but never defined [enabled by default]
src/spi.h:22:20: warning: inline function 'spi_write' declared but never defined [enabled by default]
src/spfd54124b.h:96:20: warning: inline function 'SPFD54124B_write_pixel' declared but never defined [enabled by default]
src/spfd54124b.h:95:20: warning: inline function 'SPFD54124B_write_param' declared but never defined [enabled by default]
src/spfd54124b.h:94:20: warning: inline function 'SPFD54124B_write_cmd' declared but never defined [enabled by default]
src/spi.h:22:20: warning: inline function 'spi_write' declared but never defined [enabled by default]
src/pomodoro.c: In function 'main':
src/spfd54124b.h:94:20: warning: inlining failed in call to 'SPFD54124B_write_cmd': function body not available [-Winline]
src/pomodoro.c:29:25: warning: called from here [-Winline]
src/spfd54124b.h:94:20: warning: inlining failed in call to 'SPFD54124B_write_cmd': function body not available [-Winline]
src/pomodoro.c:31:25: warning: called from here [-Winline]
src/spfd54124b.h:94:20: warning: inlining failed in call to 'SPFD54124B_write_cmd': function body not available [-Winline]
src/pomodoro.c:35:25: warning: called from here [-Winline]
src/spfd54124b.h:94:20: warning: inlining failed in call to 'SPFD54124B_write_cmd': function body not available [-Winline]
src/pomodoro.c:36:25: warning: called from here [-Winline]
src/spfd54124b.h:96:20: warning: inlining failed in call to 'SPFD54124B_write_pixel': function body not available [-Winline]
src/pomodoro.c:40:31: warning: called from here [-Winline]
src/spfd54124b.h:94:20: warning: inlining failed in call to 'SPFD54124B_write_cmd': function body not available [-Winline]
src/pomodoro.c:43:25: warning: called from here [-Winline]

c99 のさまざまなインライン化の選択肢を理解しているかどうかはわかりません。

score 10 · Accepted Answer

必要な方法とはまったく逆の方法で物事を持っています。ヘッダーでは、次を使用する必要があります。

inline void SPFD54124B_write_cmd(uint16_t command)
{
    spi_write(command, CMD_WIDTH);
}

このヘッダーを含む翻訳単位では、これにより、外部リンケージを持つインライン関数が作成されます。これらの翻訳単位の1 つだけに宣言を配置する必要があります。

extern void SPFD54124B_write_cmd(uint16_t);

inlineこれは (ヘッダーからの定義と共に) 関数の外部定義を作成します。externヘッダーを含むが宣言を含まない他のファイルは、関数のインライン定義を作成します。定義はその翻訳単位でのみ使用できますが、他の場所での外部定義を禁止しません。

合計すると、関数の外部定義が 1 つになり、ヘッダーを含む各ファイルにも、外部以外の定義が使用可能になります。コンパイラはどちらも使用できます。概念的にはSPFD54124B_write_cmd、プログラム全体で呼び出される関数は 1 つだけです。たとえば、関数のアドレスを複数の変換単位で取得すると、同じ値が得られるはずです。

別の方法として、これをヘッダーに入れることができます。

static inline void SPFD54124B_write_cmd(uint16_t command)
{
    spi_write(command, CMD_WIDTH);
}

extern宣言をまったく使用しません。これにより、ヘッダーを含む各ファイルに内部リンケージを持つインライン関数が作成されます。関数の外部定義はまったくなく、概念的には、ヘッダーを含む各翻訳単位には、関数の独自の独立したコピーがあります。

(後世のために、GCC の現在のデフォルトモードは "gnu89" であり、これはC99 セマンティクスを実装していませんinline)

score 4 · Accepted Answer

関数を実際にインライン化できるようにするには、ほとんどの場合、ヘッダーファイルで定義する必要があります。

そうしないと、ほとんどのコンパイラは実際に関数をインライン化しません。

したがって、私の提案は、実際の関数の内容をヘッダーファイルに移動することです。

inline void SPFD54124B_write_cmd(uint16_t command)
{
    spi_write(command, CMD_WIDTH);
}

c - gcc を使用した c99 インライン セマンティクス (mspgcc)

2 に答える 2

Related

Reference

c - gcc を使用した c99 インラインセマンティクス (mspgcc)