musl - musl - an implementation of the standard library for Linux-based systems

musl - an implementation of the standard library for Linux-based systems

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author	Rich Felker <dalias@aerifal.cx>	2018年09月14日 23:08:53 -0400
committer	Rich Felker <dalias@aerifal.cx>	2018年09月14日 23:08:53 -0400
commit	e13063aad7aee341d278d2a879a76ec7b59b2ad8 (patch)
tree	312126a3ac1514eadb3ea88d4a73703f5291c8b2 /src
parent	da55d4884bf26ce31cd6a64ed176019c2ba9839a (diff)
download	musl-e13063aad7aee341d278d2a879a76ec7b59b2ad8.tar.gz

add hidden version of &errno accessor function

this significantly improves codegen in functions that need to access errno but otherwise have no need for a GOT pointer. we could probably improve it much more by including an inline version of the &errno accessor function, but that depends on having the definitions of struct __pthread and __pthread_self(), which at present would expose a lot more than is appropriate. moving them to a small tls.h later might make this more reasonable.

Diffstat (limited to 'src')

-rw-r--r--

src/errno/__errno_location.c

-rw-r--r--

src/include/errno.h

2 files changed, 13 insertions, 0 deletions

diff --git a/src/errno/__errno_location.c b/src/errno/__errno_location.c
index ad9f9241..7f9d6027 100644
--- a/src/errno/__errno_location.c
+++ b/src/errno/__errno_location.c

@@ -5,3 +5,5 @@ int *__errno_location(void)

{

return &__pthread_self()->errno_val;

}

+weak_alias(__errno_location, ___errno_location);

diff --git a/src/include/errno.h b/src/include/errno.h
new file mode 100644
index 00000000..54a38ff4
--- /dev/null
+++ b/src/include/errno.h

@@ -0,0 +1,11 @@

+#ifndef ERRNO_H

+#define ERRNO_H

+#include "../../include/errno.h"

+hidden int *___errno_location(void);

+#undef errno

+#define errno (*___errno_location())

+#endif

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