mirror of
https://gcc.gnu.org/git/gcc.git
synced 2026-02-22 12:00:03 -05:00
c8894b6811
D front-end changes: - Import latest fixes from dmd v2.110.0-rc.1. D runtime changes: - Import latest fixes from druntime v2.110.0-rc.1. Phobos changes: - Import latest fixes from phobos v2.110.0-rc.1. Included in the merge are fixes for the following PRs: PR d/118438 PR d/118448 PR d/118449 gcc/d/ChangeLog: * dmd/MERGE: Merge upstream dmd d6f693b46a. * d-incpath.cc (add_import_paths): Update for new front-end interface. libphobos/ChangeLog: * libdruntime/MERGE: Merge upstream druntime d6f693b46a. * src/MERGE: Merge upstream phobos 336bed6d8. * testsuite/libphobos.init_fini/custom_gc.d: Adjust test.
117 lines
3.6 KiB
D
117 lines
3.6 KiB
D
/**********************************************
|
|
To provide access to features that would be otherwise counterproductive or
|
|
difficult to implement, compilers provide an interface consisting of a set
|
|
of builtins (also called intrinsics) which can be called like normal functions.
|
|
|
|
This module exposes builtins both common to all D compilers
|
|
(those provided by the frontend) and specific to the host compiler i.e. those
|
|
specific to either LLVM or GCC (`ldc.intrinsics` and `gcc.builtins` are publicly imported, respectively).
|
|
Host-specific intrinsics cannot be reliably listed here, however listings can be found
|
|
at the documentation for the relevant backends, i.e.
|
|
$(LINK2 https://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html, GCC) and
|
|
$(LINK2 https://llvm.org/docs/LangRef.html, LLVM). It should be noted that not all
|
|
builtins listed are necessarily supported by the host compiler, please file a bug
|
|
if this is the case for your workload.
|
|
|
|
Use of this module reduces the amount of conditional compilation needed
|
|
to use a given builtin. For example, to write a target independent function
|
|
that uses prefetching we can write the following:
|
|
---
|
|
float usePrefetch(float[] x)
|
|
{
|
|
// There is only one import statement required rather than two (versioned) imports
|
|
import core.builtins;
|
|
version (GNU)
|
|
__builtin_prefetch(x.ptr);
|
|
version (LDC)
|
|
/+
|
|
For the curious: 0, 3, 1 mean `x` will only be read-from (0), it will be used
|
|
very often (3), and it should be fetched to the data-cache (1).
|
|
+/
|
|
llvm_prefetch(x.ptr, 0, 3, 1);
|
|
const doMath = blahBlahBlah;
|
|
return doMath;
|
|
}
|
|
---
|
|
|
|
|
|
Copyright: Copyright © 2021, The D Language Foundation
|
|
License: $(LINK2 http://www.boost.org/LICENSE_1_0.txt, Boost License 1.0)
|
|
Authors: Walter Bright
|
|
Source: $(DRUNTIMESRC core/builtins.d)
|
|
*/
|
|
|
|
module core.builtins;
|
|
|
|
version (GNU)
|
|
public import gcc.builtins;
|
|
|
|
version (LDC)
|
|
public import ldc.intrinsics;
|
|
|
|
/// Writes `s` to `stderr` during CTFE (does nothing at runtime).
|
|
void __ctfeWrite(scope const(char)[] s) @nogc @safe pure nothrow {}
|
|
|
|
version (GNU)
|
|
{
|
|
/// https://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#index-_005f_005fbuiltin_005fexpect
|
|
alias expect = __builtin_expect;
|
|
/// https://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#index-_005f_005fbuiltin_005ftrap
|
|
alias trap = __builtin_trap;
|
|
}
|
|
else version (LDC)
|
|
{
|
|
/// https://llvm.org/docs/LangRef.html#llvm-expect-intrinsic
|
|
alias expect = llvm_expect;
|
|
debug
|
|
/// https://llvm.org/docs/LangRef.html#llvm-debugtrap-intrinsic
|
|
alias trap = llvm_debugtrap;
|
|
else
|
|
/// https://llvm.org/docs/LangRef.html#llvm-trap-intrinsic
|
|
alias trap = llvm_trap;
|
|
}
|
|
else version (DigitalMars)
|
|
{
|
|
pragma(inline, true)
|
|
T expect(T)(T val, T expected) if (__traits(isIntegral, T))
|
|
{
|
|
return val;
|
|
}
|
|
|
|
/// Execute target dependent trap instruction, if supported.
|
|
/// Otherwise, abort execution.
|
|
pragma(inline, true)
|
|
void trap()
|
|
{
|
|
debug
|
|
{
|
|
version(D_InlineAsm_X86)
|
|
asm nothrow @nogc pure @trusted { int 3; }
|
|
}
|
|
assert(0);
|
|
}
|
|
}
|
|
|
|
/// Provide static branch and value hints for the LDC/GDC compilers.
|
|
/// DMD ignores these hints.
|
|
pragma(inline, true) bool likely()(bool b) { return !!expect(b, true); }
|
|
/// ditto
|
|
pragma(inline, true) bool unlikely()(bool b) { return !!expect(b, false); }
|
|
|
|
///
|
|
@nogc nothrow pure @safe unittest
|
|
{
|
|
int x = 12;
|
|
|
|
expect(x, 12);
|
|
|
|
if (likely(x > 0))
|
|
{
|
|
// ...
|
|
}
|
|
else if (unlikely(x == int.min))
|
|
{
|
|
// ...
|
|
}
|
|
}
|