MSL: Support inline uniform blocks in argument buffers.

Here, the inline uniform block is explicit: we instantiate the buffer
block itself in the argument buffer, instead of a pointer to the buffer.
I just hope this will work with the `MTLArgumentDescriptor` API...

Note that Metal recursively assigns individual members of embedded
structs IDs. This means for automatic assignment that we have to
calculate the binding stride for a given buffer block. For MoltenVK,
we'll simply increment the ID by the size of the inline uniform block.
Then the later IDs will never conflict with the inline uniform block. We
can get away with this because Metal doesn't require that IDs be
contiguous, only monotonically increasing.

1 files changed, 11 insertions, 0 deletions

diff --git a/main.cpp b/main.cpp
index 60d59c67..f19bc9b5 100644
--- a/main.cpp
+++ b/main.cpp
@@ -529,6 +529,7 @@ struct CLIArguments
 	SmallVector<uint32_t> msl_discrete_descriptor_sets;
 	SmallVector<uint32_t> msl_device_argument_buffers;
 	SmallVector<pair<uint32_t, uint32_t>> msl_dynamic_buffers;
+	SmallVector<pair<uint32_t, uint32_t>> msl_inline_uniform_blocks;
 	SmallVector<PLSArg> pls_in;
 	SmallVector<PLSArg> pls_out;
 	SmallVector<Remap> remaps;
@@ -612,6 +613,7 @@ static void print_help()
 	                "\t[--msl-view-index-from-device-index]\n"
 	                "\t[--msl-dispatch-base]\n"
 	                "\t[--msl-dynamic-buffer <set index> <binding>]\n"
+	                "\t[--msl-inline-uniform-block <set index> <binding>]\n"
 	                "\t[--msl-decoration-binding]\n"
 	                "\t[--msl-force-active-argument-buffer-resources]\n"
 	                "\t[--hlsl]\n"
@@ -812,6 +814,8 @@ static string compile_iteration(const CLIArguments &args, std::vector<uint32_t>
 		uint32_t i = 0;
 		for (auto &v : args.msl_dynamic_buffers)
 			msl_comp->add_dynamic_buffer(v.first, v.second, i++);
+		for (auto &v : args.msl_inline_uniform_blocks)
+			msl_comp->add_inline_uniform_block(v.first, v.second);
 	}
 	else if (args.hlsl)
 		compiler.reset(new CompilerHLSL(move(spirv_parser.get_parsed_ir())));
@@ -1153,6 +1157,13 @@ static int main_inner(int argc, char *argv[])
 	cbs.add("--msl-decoration-binding", [&args](CLIParser &) { args.msl_decoration_binding = true; });
 	cbs.add("--msl-force-active-argument-buffer-resources",
 	        [&args](CLIParser &) { args.msl_force_active_argument_buffer_resources = true; });
+	cbs.add("--msl-inline-uniform-block", [&args](CLIParser &parser) {
+		args.msl_argument_buffers = true;
+		// Make sure next_uint() is called in-order.
+		uint32_t desc_set = parser.next_uint();
+		uint32_t binding = parser.next_uint();
+		args.msl_inline_uniform_blocks.push_back(make_pair(desc_set, binding));
+	});
 	cbs.add("--extension", [&args](CLIParser &parser) { args.extensions.push_back(parser.next_string()); });
 	cbs.add("--rename-entry-point", [&args](CLIParser &parser) {
 		auto old_name = parser.next_string();