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Some calling convention work for x86-64:

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- Implement x86-64 extern(C), hopefully correctly.
 - Tried to be a bit smarter about extern(D) while I was there.

Interestingly, this code seems to be generating more efficient code than
gcc and llvm-gcc in some edge cases, like returning a `{ [7 x i8] }` loaded from
a stack slot from an extern(C) function. (gcc generates 7 1-byte loads, while
this code generates a 4-byte, a 2-byte and a 1-byte load)

I also added some changes to make sure structs being returned from functions or
passed in as parameters are stored in memory where the rest of the backend seems
to expect them to be. These should be removed when support for first-class
aggregates improves.
This commit is contained in:
Frits van Bommel
2009-03-06 16:00:47 +01:00
parent 79bc6230df
commit 27d3ab4546
10 changed files with 749 additions and 118 deletions
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38
gen/tocall.cpp
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@@ -217,6 +217,11 @@ void DtoBuildDVarArgList(std::vector<LLValue*>& args, std::vector<llvm::Attribut
DValue* DtoCallFunction(Loc& loc, Type* resulttype, DValue* fnval, Expressions* arguments)
{
if (Logger::enabled()) {
Logger::println("DtoCallFunction()");
}
LOG_SCOPE
// the callee D type
Type* calleeType = fnval->getType();
@@ -386,6 +391,15 @@ DValue* DtoCallFunction(Loc& loc, Type* resulttype, DValue* fnval, Expressions*
int j = tf->fty->reverseParams ? beg + n - i - 1 : beg + i;
// Hack around LDC assuming structs are in memory:
// If the function wants a struct, and the argument value is a
// pointer to a struct, load from it before passing it in.
if (argval->getType()->ty == Tstruct
&& isaPointer(arg) && !isaPointer(callableTy->getParamType(j))) {
Logger::println("Loading struct type for function argument");
arg = DtoLoad(arg);
}
// parameter type mismatch, this is hard to get rid of
if (arg->getType() != callableTy->getParamType(j))
{
@@ -468,24 +482,24 @@ DValue* DtoCallFunction(Loc& loc, Type* resulttype, DValue* fnval, Expressions*
// get return value
LLValue* retllval = (retinptr) ? args[0] : call.getInstruction();
if (tf->linkage == LINKintrinsic)
{
// Ignore ABI for intrinsics
Type* rettype = tf->next;
if (rettype->ty == Tstruct) {
// LDC assumes structs are in memory, so put it there.
LLValue* mem = DtoAlloca(retllval->getType());
DtoStore(retllval, mem);
retllval = mem;
}
}
else if (!retinptr)
// Ignore ABI for intrinsics
if (tf->linkage != LINKintrinsic && !retinptr)
{
// do abi specific return value fixups
DImValue dretval(tf->next, retllval);
retllval = tf->fty->getRet(tf->next, &dretval);
}
// Hack around LDC assuming structs are in memory:
// If the function returns a struct, and the return value is not a
// pointer to a struct, store it to a stack slot before continuing.
if (tf->next->ty == Tstruct && !isaPointer(retllval)) {
Logger::println("Storing return value to stack slot");
LLValue* mem = DtoAlloca(retllval->getType());
DtoStore(retllval, mem);
retllval = mem;
}
// repaint the type if necessary
if (resulttype)
{