Indexed indirect draws already let vkCmdDrawIndexedIndirect read their
counts, but a non-indexed DRAW_INDIRECT read its four arguments on the
CPU. When a compute pass had just written them (UE writes rectangle-list
draw arguments this way every frame), the read downloaded the buffer and
waited for the whole GPU: about one 20-50 ms stall per frame in Silent
Hill: The Short Message's menu.
The interpreter now hands the argument address to the host when it draws
non-indexed indirect draws on the GPU (deferring the instance count read
as the indexed path does), and the executor records vkCmdDrawIndirect.
The guest layout (vertexCount, instanceCount, firstVertex, firstInstance)
is VkDrawIndirectCommand. Rectangle lists use the general rectangle-list
variant, since the count is unknown; fans, polygons, legacy lists and
targetless draws (which may be retained and replayed) still read the
arguments on the CPU. SHARPEMU_CPU_INDIRECT_DRAW=1 keeps the CPU path.
(cherry picked from commit f2b91befb7dd27d65a35546f1e57dc88f04a5c82)
0aa611e317