view tools/binding/llvmsample3.d @ 1410:cc2d8a7388c7

Count the sret register as well when keeping track of how many integer registers are available for extern(C) functions on x86-64. Interestingly, llvm-g++ seems to have a very similar bug: http://llvm.org/pr4242 (So this breaks ABI-compatibility with llvm-gcc for this corner case, but gains it with gcc...) To clarify, this is about code like this: {{{ struct S { void*[3] data; } struct T { void*[2] data; } // The T should be passed in memory, and p in the last int register. extern(C) S fail(int, int, int, int, T t, void* p) { S s; s.data[0] = t.data[0]; s.data[1] = t.data[1]; s.data[2] = p; return s; } }}} which should generate code functionally equivalent to this: {{{ extern(C) S* succeed(S* s, int, int, int, int, T t, void* p) { s.data[0] = t.data[0]; s.data[1] = t.data[1]; s.data[2] = p; return s; } }}} (with the same definitions for S and T)
author Frits van Bommel <fvbommel wxs.nl>
date Fri, 22 May 2009 13:17:06 +0200
parents 1ba61de8796b
children
line wrap: on
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// simple example that shows off getting D wrappers from C values.
module llvmsample3;

import llvm.c.Core;
import llvm.llvm;

void main()
{
    auto m = new Module("sample3");

    // global int32
    auto gi = m.addGlobal(Type.Int32, "myint");
    gi.initializer = ConstantInt.GetU(Type.Int32, 42);

    // this is not a cached value, it's recreated dynamically
    auto _i = gi.initializer;
    auto ci = cast(ConstantInt)_i;
    assert(ci !is null);
    ci.dump;

    // global struct
    auto st = StructType.Get([Type.Double,Type.Double,Type.Double]);
    auto gs = m.addGlobal(st, "mystruct");
    auto elems = new Constant[3];
    foreach(i,ref e; elems)
        e = ConstantReal.Get(Type.Double, i+1);
    gs.initializer = ConstantStruct.Get(elems);

    // again this is not a cached value.
    auto s = gs.initializer;
    auto cs = cast(ConstantStruct)s;
    assert(cs !is null);

    cs.dump;
}