/// <inheritdoc/>
protected override Tuple <IAssembly, IEnumerable <IAssembly> > RewriteAssemblies(
Tuple <IAssembly, IEnumerable <IAssembly> > MainAndOtherAssemblies,
IBinder Binder,
ICompilerLog Log)
{
// In addition to emitting LLVM IR from managed code, flame-llvm must also
// set up an environment in which managed code can run. Part of this
// environment is the 'main' function: managed code expects an entry point
// to look like this: `void|int Main(|string[])`, whereas a C 'main' function
// must have the following signature: `int main(int, byte**)`.
//
// To bridge this divide, we'll generate a 'main' function and use that to
// call the entry point.
var originalAsm = MainAndOtherAssemblies.Item1;
var originalEntryPoint = originalAsm.GetEntryPoint();
if (originalEntryPoint == null)
{
// We can't rewrite the entry point of an assembly that doesn't
// have an entry point.
return(MainAndOtherAssemblies);
}
// Generate the following class:
//
// public static class __entry_point
// {
// [#builtin_abi("C")]
// [#builtin_llvm_linkage(external)]
// public static int main(int argc, byte** argv)
// {
// try
// {
// var parsedArgs = Environment.Initialize(argc, argv);
// return actual_entry_point(...);
// // --or--
// actual_entry_point(...);
// return 0;
// }
// catch (Exception ex)
// {
// Environment.HandleFatalException(ex);
// return 1;
// }
// }
// }
var mainAsm = new DescribedAssembly(
originalAsm.Name,
originalAsm.AssemblyVersion,
Binder.Environment);
var epType = new DescribedType(new SimpleName("__entry_point"), mainAsm);
epType.AddAttribute(PrimitiveAttributes.Instance.StaticTypeAttribute);
var mainThunk = new DescribedBodyMethod(
new SimpleName("main"), epType, PrimitiveTypes.Int32, true);
mainThunk.AddAttribute(new LLVMLinkageAttribute(LLVMLinkage.LLVMExternalLinkage));
mainThunk.AddAttribute(LLVMAttributes.CreateAbiAttribute("C"));
mainThunk.AddParameter(new DescribedParameter("argc", PrimitiveTypes.Int32));
mainThunk.AddParameter(
new DescribedParameter(
"argv",
PrimitiveTypes.UInt8
.MakePointerType(PointerKind.TransientPointer)
.MakePointerType(PointerKind.TransientPointer)));
if (originalEntryPoint.HasSameSignature(mainThunk))
{
// We don't have to rewrite the entry point if the existing entry point
// already has the expected form.
return(MainAndOtherAssemblies);
}
var epCall = CreateEntryPointCall(originalEntryPoint, mainThunk, Binder);
mainThunk.Body = epCall.Type.GetIsInteger()
? (IStatement) new ReturnStatement(
new StaticCastExpression(epCall, PrimitiveTypes.Int32).Simplify())
: new BlockStatement(new IStatement[]
{
new ExpressionStatement(epCall),
new ReturnStatement(new IntegerExpression(0))
});
var handleExceptionMethod = BindEnvironmentHandleFatalExceptionMethod(Binder);
if (handleExceptionMethod != null)
{
var exceptionParam = handleExceptionMethod.Parameters.Single <IParameter>();
var catchClause = new CatchClause(
new DescribedVariableMember(
exceptionParam.Name,
exceptionParam.ParameterType));
catchClause.Body = new BlockStatement(new IStatement[]
{
new ExpressionStatement(
new InvocationExpression(
handleExceptionMethod,
null,
new IExpression[]
{
catchClause.ExceptionVariable.CreateGetExpression()
})),
new ReturnStatement(new IntegerExpression(1))
});
mainThunk.Body = new TryStatement(
mainThunk.Body,
new CatchClause[] { catchClause });
}
epType.AddMethod(mainThunk);
mainAsm.AddType(epType);
mainAsm.EntryPoint = mainThunk;
return(new Tuple <IAssembly, IEnumerable <IAssembly> >(
mainAsm,
new IAssembly[] { originalAsm }.Concat <IAssembly>(MainAndOtherAssemblies.Item2)));
}
