[dmd-cxx] Use run-time allocated mutexes for plain synchronized statements
#11902
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Thanks for your pull request, @ibuclaw! Bugzilla referencesYour PR doesn't reference any Bugzilla issue. If your PR contains non-trivial changes, please reference a Bugzilla issue or create a manual changelog. Testing this PR locallyIf you don't have a local development environment setup, you can use Digger to test this PR: dub run digger -- build "dmd-cxx + dmd#11902" |
thewilsonator
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synchronized statementssynchronized statements
…tements
Synchronized statements have two forms, `synchronized` and `synchronized(exp)`.
When there is no expression argument, a global mutex is created using a static
buffer big enough to store the platform dependant critical section type and a
pointer field.
Example:
```
void main()
{
synchronized {
// __gshared byte[40 + 8] __critsec;
// _d_criticalenter(&__critsec[0]);
// scope(exit) _d_criticalexit(&__critsec[0]);
(cast() counter) += 1;
}
}
```
This implementation suffers from a couple deficiencies. Neither the size nor
alignment of the `critsec` buffer are obtained from the OS critical section
type defined in druntime. As a result, if the size allocated by the compiler is
too small, or the platform has strict alignment requirements, then the program
run-time will crash on entering the synchronized statement.
This code will now call a new implementation that allocates the critical
section lazily at run-time.
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The allocation of mutex objects for synchronized statements has been moved to the library as of merging druntime 58560d51. All support code in the compiler for getting the OS critical section size has been removed along with it. Reviewed-on: dlang/dmd#11902 dlang/druntime#3248 gcc/ChangeLog: * config/aarch64/aarch64-linux.h (GNU_USER_TARGET_D_CRITSEC_SIZE): Remove. * config/glibc-d.c (glibc_d_critsec_size): Likewise. (TARGET_D_CRITSEC_SIZE): Likewise. * config/i386/linux-common.h (GNU_USER_TARGET_D_CRITSEC_SIZE): Likewise. * config/sol2-d.c (solaris_d_critsec_size): Likewise. (TARGET_D_CRITSEC_SIZE): Likewise. * doc/tm.texi.in (TARGET_D_CRITSEC_SIZE): Likewise. * doc/tm.texi: Regenerate. gcc/d/ChangeLog: * dmd/MERGE: Merge upstream dmd bec5973b0. * d-target.cc (Target::critsecsize): Remove. * d-target.def: Remove d_critsec_size. libphobos/ChangeLog: * libdruntime/MERGE: Merge upstream druntime 58560d51.
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Backport of #11824, depends on dlang/druntime#3248