tools/trace: add initial interposed Vulkan tracing library

CMakeLists.txt

@@ -16,6 +16,7 @@ endif ()
 ###############################################################################
 set (GENERATED_PREFIX "${CMAKE_CURRENT_BINARY_DIR}/cruft/vk/")
 file (MAKE_DIRECTORY "${GENERATED_PREFIX}/load")
+file (MAKE_DIRECTORY "${GENERATED_PREFIX}/tools")
 
 
 if (WIN32)
@@ -33,6 +34,7 @@ OUTPUT
     "${GENERATED_PREFIX}/vk.hpp"
     "${GENERATED_PREFIX}/load/dispatch.cpp"
     "${GENERATED_PREFIX}/load/vtable.hpp"
+    "${GENERATED_PREFIX}/tools/trace.cpp"
 COMMENT
     "[spec.py] vk.hpp"
 COMMAND
@@ -42,6 +44,7 @@ COMMAND
     "--dst" "${GENERATED_PREFIX}/vk.hpp"
     "--load" "${GENERATED_PREFIX}/load/vtable.hpp"
     "--dispatch" "${GENERATED_PREFIX}/load/dispatch.cpp"
+    "--trace" "${GENERATED_PREFIX}/tools/trace.cpp"
     "--platform" "${VK_PLATFORM}"
 DEPENDS
     "${CMAKE_CURRENT_SOURCE_DIR}/tools/spec.py"
@@ -204,6 +207,18 @@ endforeach ()
 target_link_libraries (vk_info cruft-vk cruft-vk-load)
 target_link_libraries (vk_hello ${NC_CXX_STDCXXFS} cruft cruft-vk glfw vulkan)
 
+add_library (trace SHARED
+    "${GENERATED_PREFIX}/tools/trace.cpp"
+)
+
+target_include_directories (trace
+PUBLIC
+    "${CMAKE_CURRENT_SOURCE_DIR}"
+    "${CMAKE_CURRENT_BINARY_DIR}"
+    "${CMAKE_CURRENT_SOURCE_DIR}/specs/include/vulkan"
+)
+
+target_link_libraries(trace cruft-vk)
 
 ##-----------------------------------------------------------------------------
 add_dependencies (vk_hello hello.vert.spv hello.frag.spv)

tools/spec.py

@@ -991,6 +991,54 @@ def write_dispatch(dst: TextIO, q: List[Type], reg: Registry):
         }}
         """)
 
+def write_trace(dst: TextIO, q: List[Type], reg: Registry):
+    dst.write("""
+        #include <cruft/vk/vk.hpp>
+        #include <cruft/vk/load/vtable.hpp>
+        #include <cruft/vk/ostream.hpp>
+        #include <iostream>
+        #include <dlfcn.h>
+        #include <cstring>
+        
+        static void* g_lib;
+        
+        void init [[gnu::constructor]] (void) {
+            g_lib = dlopen (getenv ("REAL_VULKAN"), RTLD_LAZY | RTLD_LOCAL);
+        } 
+        
+        void deinit [[gnu::destructor]] (void) {
+            dlclose (g_lib);
+            g_lib = nullptr;
+        }
+        #pragma GCC diagnostic ignored "-Wsign-promo"
+    """)
+
+
+    for obj in (i for i in q if isinstance(i, Command)):
+        inner = ""
+        if obj.name in [ 'vkGetInstanceProcAddr' ]:
+            inner = """
+            
+            #define FWD(NAME) \\
+            if (!strcmp(#NAME,pName)) { \\
+                if (fn (nullptr, #NAME)) \\
+                    return (PFN_vkVoidFunction)NAME; \\
+                else \\
+                    return nullptr;\\
+            }
+            MAP_INSTANCE_COMMANDS(FWD)
+            #undef FWD
+            std::clog << "Missed: " << pName << '\\n';
+            """
+
+        dst.write(f"""
+        extern "C" {obj.result} {rename(obj.name)} ({", ".join(p.param for p in obj.params)}) noexcept {{
+            std::clog << "{obj.name}" << " " << {'<< " " << '.join (p.name for p in obj.params)} << '\\n';
+            static auto fn = reinterpret_cast<decltype({obj.name})*> (dlsym (g_lib, "{obj.name}"));
+            {inner}
+            return (*fn) ({','.join (p.name for p in obj.params)});
+        }}""")
+
 
 ###############################################################################
 import argparse
@@ -1005,6 +1053,7 @@ def main():
     parser.add_argument('--dst', type=str, help='the output path for the result')
     parser.add_argument('--load', type=str, help='the output path for the loading routines')
     parser.add_argument('--dispatch', type=str, help="the output path for function dispatch")
+    parser.add_argument('--trace', type=str, help="the output path for the vulkan tracing library")
     parser.add_argument(
         '--platform',
         type=str,
@@ -1104,6 +1153,9 @@ def main():
     with open(args.dispatch, 'w') as dst:
         write_dispatch(dst, q, reg)
 
+    with open(args.trace, 'w') as dst:
+        write_trace(dst, q, reg)
+
 
 # -----------------------------------------------------------------------------
 if __name__ == '__main__':