static int resultSize(ResultType resultType) {
switch (resultType.nativeType()) {
case SCHAR:
case UCHAR:
case SSHORT:
case USHORT:
case SINT:
case UINT:
case SLONG:
case ULONG:
case POINTER:
return 4;
case SLONG_LONG:
case ULONG_LONG:
return 8;
case FLOAT:
case DOUBLE:
return 16;
case VOID:
return 0;
default:
throw new IllegalArgumentException("invalid return type " + resultType);
}
}
@Override
void compile(
long function,
String name,
ResultType resultType,
ParameterType[] parameterTypes,
Class resultClass,
Class[] parameterClasses,
CallingConvention convention,
boolean saveErrno) {
int psize = 0;
for (ParameterType t : parameterTypes) {
psize += parameterSize(t);
}
int rsize = resultSize(resultType);
//
// JNI functions all look like:
// foo(JNIEnv* env, jobject self, arg...)
// We need to align the stack to 16 bytes, then copy all the old args
// into the new parameter space.
// It already has 4 bytes pushed (the return address) so we need to account for that.
//
final int stackadj = align(Math.max(psize, rsize) + 4, 16) - 4;
Assembler a = new Assembler(X86_32);
a.sub(esp, imm(stackadj));
// copy and convert the parameters from the orig stack to the new location
for (int i = 0, srcoff = 0, dstoff = 0; i < parameterTypes.length; i++) {
int srcParameterSize = parameterSize(parameterClasses[i]);
int dstParameterSize = parameterSize(parameterTypes[i]);
int disp = stackadj + 4 + 8 + srcoff;
switch (parameterTypes[i].nativeType()) {
case SCHAR:
case SSHORT:
a.movsx(eax, ptr(esp, disp, parameterTypes[i].nativeType()));
break;
case UCHAR:
case USHORT:
a.movzx(eax, ptr(esp, disp, parameterTypes[i].nativeType()));
break;
default:
a.mov(eax, dword_ptr(esp, disp));
break;
}
a.mov(dword_ptr(esp, dstoff), eax);
if (dstParameterSize > 4) {
if (parameterTypes[i].nativeType() == NativeType.SLONG_LONG
&& long.class != parameterClasses[i]) {
// sign extend from int.class -> long long
a.sar(eax, imm(31));
} else if (parameterTypes[i].nativeType() == NativeType.ULONG_LONG
&& long.class != parameterClasses[i]) {
// zero extend from int.class -> unsigned long long
a.mov(dword_ptr(esp, dstoff + 4), imm(0));
} else {
a.mov(eax, dword_ptr(esp, disp + 4));
}
a.mov(dword_ptr(esp, dstoff + 4), eax);
}
dstoff += dstParameterSize;
srcoff += srcParameterSize;
}
// Call to the actual native function
a.call(imm(function & 0xffffffffL));
if (saveErrno) {
int save = 0;
switch (resultType.nativeType()) {
case FLOAT:
a.fstp(dword_ptr(esp, save));
break;
case DOUBLE:
a.fstp(qword_ptr(esp, save));
break;
case SLONG_LONG:
case ULONG_LONG:
a.mov(dword_ptr(esp, save), eax);
a.mov(dword_ptr(esp, save + 4), edx);
break;
case VOID:
// No need to save for void values
break;
default:
a.mov(dword_ptr(esp, save), eax);
}
// Save the errno in a thread-local variable
a.call(imm(errnoFunctionAddress & 0xffffffffL));
// Retrieve return value and put it back in the appropriate return register
switch (resultType.nativeType()) {
case FLOAT:
a.fld(dword_ptr(esp, save));
break;
case DOUBLE:
a.fld(qword_ptr(esp, save));
break;
case SCHAR:
a.movsx(eax, byte_ptr(esp, save));
break;
case UCHAR:
a.movzx(eax, byte_ptr(esp, save));
break;
case SSHORT:
a.movsx(eax, word_ptr(esp, save));
break;
case USHORT:
a.movzx(eax, word_ptr(esp, save));
break;
case SLONG_LONG:
case ULONG_LONG:
a.mov(eax, dword_ptr(esp, save));
a.mov(edx, dword_ptr(esp, save + 4));
break;
case VOID:
// No need to save for void values
break;
default:
a.mov(eax, dword_ptr(esp, save));
}
} else {
switch (resultType.nativeType()) {
case SCHAR:
a.movsx(eax, al);
break;
case UCHAR:
a.movzx(eax, al);
break;
case SSHORT:
a.movsx(eax, ax);
break;
case USHORT:
a.movzx(eax, ax);
break;
}
}
if (long.class == resultClass) {
// sign or zero extend the result to 64 bits
switch (resultType.nativeType()) {
case SCHAR:
case SSHORT:
case SINT:
case SLONG:
// sign extend eax to edx:eax
a.mov(edx, eax);
a.sar(edx, imm(31));
break;
case UCHAR:
case USHORT:
case UINT:
case ULONG:
case POINTER:
a.mov(edx, imm(0));
break;
}
}
// Restore esp to the original position and return
a.add(esp, imm(stackadj));
a.ret();
stubs.add(new Stub(name, sig(resultClass, parameterClasses), a));
}
boolean canCompile(
ResultType returnType, ParameterType[] parameterTypes, CallingConvention convention) {
switch (returnType.nativeType()) {
case VOID:
case SCHAR:
case UCHAR:
case SSHORT:
case USHORT:
case SINT:
case UINT:
case SLONG:
case ULONG:
case SLONG_LONG:
case ULONG_LONG:
case FLOAT:
case DOUBLE:
case POINTER:
break;
default:
return false;
}
// There is only one calling convention; SYSV, so abort if someone tries to use stdcall
if (convention != CallingConvention.DEFAULT) {
return false;
}
int fCount = 0;
int iCount = 0;
for (ParameterType t : parameterTypes) {
switch (t.nativeType()) {
case SCHAR:
case UCHAR:
case SSHORT:
case USHORT:
case SINT:
case UINT:
case SLONG:
case ULONG:
case SLONG_LONG:
case ULONG_LONG:
case POINTER:
++iCount;
break;
case FLOAT:
case DOUBLE:
++fCount;
break;
default:
// Fail on anything else
return false;
}
}
// We can only safely compile methods with up to 6 integer and 8 floating point parameters
return true;
}
