[PATCH] D75820: tsan_interface.h: make constants static

[Emilio G. Cota via Phabricator via llvm-commits]

cota created this revision.
cota added a reviewer: dvyukov.
cota added projects: Sanitizers, LLVM.
Herald added subscribers: Sanitizers, llvm-commits.

Note that in C++ the static keyword is implicit for const objects.
In C however it is not, and we get clashes at link time after
including the header from more than one C file:

  lib.a(bar.o):(.rodata+0x0): multiple definition of `__tsan_mutex_linker_init'
  lib.a(foo.o):(.rodata+0x0): first defined here
  lib.a(bar.o):(.rodata+0xc): multiple definition of `__tsan_mutex_not_static'
  lib.a(foo.o):(.rodata+0xc): first defined here
  <snip>

Indeed both foo.o and bar.o define the clashing symbols:

  $ nm foo.o
  <snip>
  0000000000000000 R __tsan_mutex_linker_init
  000000000000000c R __tsan_mutex_not_static
  <snip>

Fix it by explicitly making the constants static.


Repository:
  rCRT Compiler Runtime

https://reviews.llvm.org/D75820

Files:
  include/sanitizer/tsan_interface.h


Index: include/sanitizer/tsan_interface.h
===================================================================
--- include/sanitizer/tsan_interface.h
+++ include/sanitizer/tsan_interface.h
@@ -38,34 +38,34 @@
 
 // Mutex has static storage duration and no-op constructor and destructor.
 // This effectively makes tsan ignore destroy annotation.
-const unsigned __tsan_mutex_linker_init      = 1 << 0;
+static const unsigned __tsan_mutex_linker_init      = 1 << 0;
 // Mutex is write reentrant.
-const unsigned __tsan_mutex_write_reentrant  = 1 << 1;
+static const unsigned __tsan_mutex_write_reentrant  = 1 << 1;
 // Mutex is read reentrant.
-const unsigned __tsan_mutex_read_reentrant   = 1 << 2;
+static const unsigned __tsan_mutex_read_reentrant   = 1 << 2;
 // Mutex does not have static storage duration, and must not be used after
 // its destructor runs.  The opposite of __tsan_mutex_linker_init.
 // If this flag is passed to __tsan_mutex_destroy, then the destruction
 // is ignored unless this flag was previously set on the mutex.
-const unsigned __tsan_mutex_not_static       = 1 << 8;
+static const unsigned __tsan_mutex_not_static       = 1 << 8;
 
 // Mutex operation flags:
 
 // Denotes read lock operation.
-const unsigned __tsan_mutex_read_lock        = 1 << 3;
+static const unsigned __tsan_mutex_read_lock        = 1 << 3;
 // Denotes try lock operation.
-const unsigned __tsan_mutex_try_lock         = 1 << 4;
+static const unsigned __tsan_mutex_try_lock         = 1 << 4;
 // Denotes that a try lock operation has failed to acquire the mutex.
-const unsigned __tsan_mutex_try_lock_failed  = 1 << 5;
+static const unsigned __tsan_mutex_try_lock_failed  = 1 << 5;
 // Denotes that the lock operation acquires multiple recursion levels.
 // Number of levels is passed in recursion parameter.
 // This is useful for annotation of e.g. Java builtin monitors,
 // for which wait operation releases all recursive acquisitions of the mutex.
-const unsigned __tsan_mutex_recursive_lock   = 1 << 6;
+static const unsigned __tsan_mutex_recursive_lock   = 1 << 6;
 // Denotes that the unlock operation releases all recursion levels.
 // Number of released levels is returned and later must be passed to
 // the corresponding __tsan_mutex_post_lock annotation.
-const unsigned __tsan_mutex_recursive_unlock = 1 << 7;
+static const unsigned __tsan_mutex_recursive_unlock = 1 << 7;
 
 // Annotate creation of a mutex.
 // Supported flags: mutex creation flags.
@@ -152,7 +152,7 @@
 
 // Flags for __tsan_switch_to_fiber:
 // Do not establish a happens-before relation between fibers
-const unsigned __tsan_switch_to_fiber_no_sync = 1 << 0;
+static const unsigned __tsan_switch_to_fiber_no_sync = 1 << 0;
 
 #ifdef __cplusplus
 }  // extern "C"


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