[Beignet] [PATCH V2] Add the PCH support when building the source.

[junyan.he at inbox.com]

From: Junyan He <junyan.he at linux.intel.com>

Because the utest grows bigger, the runtime compiling time seems a big
problem to cause the utest_run very slow.  Most of the time wastes on
re-parsing the big header file such as ocl_stdlib.h.
Using the PCH feature of Clang can shorten the compiling time a lot.
Because we build the pch file at building time, but some source
has runtime building option for LLVM, and these options may cause
the compitable problem between the pch header and the CL source code.
We fallback to build the whole header and source when we find the
options are not compitable.

Signed-off-by: Junyan He <junyan.he at linux.intel.com>
---
 backend/src/CMakeLists.txt      |   31 +++++++++++++++++++++++++++++--
 backend/src/backend/program.cpp |   36 ++++++++++++++++++++++++++++++++----
 2 files changed, 61 insertions(+), 6 deletions(-)

diff --git a/backend/src/CMakeLists.txt b/backend/src/CMakeLists.txt
index a0fe198..04b4202 100644
--- a/backend/src/CMakeLists.txt
+++ b/backend/src/CMakeLists.txt
@@ -1,5 +1,4 @@
 #add_subdirectory(llvm)
-
 macro (stringify TO_STRINGIFY_PATH TO_STRINGIFY_FILES)
 foreach (to_stringify_file ${TO_STRINGIFY_FILES})
   set (input_file ${TO_STRINGIFY_PATH}/${to_stringify_file}.h)
@@ -20,9 +19,36 @@ foreach (to_stringify_file ${TO_STRINGIFY_FILES})
 endforeach (to_stringify_file)
 endmacro (stringify)
 
+macro (generate_pch TO_GENERATE_PATH SRC_HEADERS OUTPUT_HEADER)
+    if (LLVM_VERSION_NODOT VERSION_GREATER 32)
+	set (clang_cmd -cc1 -x cl -triple spir -ffp-contract=off -emit-pch)
+    else (LLVM_VERSION_NODOT VERSION_GREATER 32)
+	if (LLVM_VERSION_NODOT VERSION_GREATER 31)
+	    set (clang_cmd -cc1 -x cl -triple nvptx -ffp-contract=off -emit-pch)
+	else (LLVM_VERSION_NODOT VERSION_GREATER 31)
+	    set (clang_cmd -cc1 -x cl -triple ptx32 -emit-pch)
+	endif (LLVM_VERSION_NODOT VERSION_GREATER 31)
+    endif (LLVM_VERSION_NODOT VERSION_GREATER 32)
+    set (output_file ${TO_GENERATE_PATH}/${OUTPUT_HEADER})
+    set (output_pch ${TO_GENERATE_PATH}/${OUTPUT_HEADER}.pch)
+    add_custom_command(
+	OUTPUT ${output_file}
+	COMMAND rm -rf ${output_file}
+	COMMAND rm -rf ${output_pch}
+	COMMAND cat ${SRC_HEADERS} > ${output_file}
+	COMMAND clang ${clang_cmd} ${output_file} -o ${output_pch}
+	MAIN_DEPENDENCY ${SRC_HEADERS}
+	)
+endmacro (generate_pch)
+
+
 set (TO_STRINGIFY_FILES ocl_stdlib ocl_common_defines)
 stringify ("${GBE_SOURCE_DIR}/src/" "${TO_STRINGIFY_FILES}")
 
+set (PCH_DEP_HEADERS ocl_common_defines.h ocl_stdlib.h)
+set (PCH_HEADER ocl_header.h)
+generate_pch ("${GBE_SOURCE_DIR}/src" "${PCH_DEP_HEADERS}" ${PCH_HEADER})
+
 if (GBE_USE_BLOB)
   set (GBE_SRC
        blob.cpp
@@ -31,7 +57,7 @@ else (GBE_USE_BLOB)
   set (GBE_SRC
     ocl_stdlib.h
     ocl_stdlib_str.cpp  # this file is auto-generated.
-    ocl_stdlib_str.cpp
+    ocl_header.h
     ocl_common_defines.h
     ocl_common_defines_str.cpp # this file is auto-generated.
     sys/vector.hpp
@@ -122,5 +148,6 @@ target_link_libraries(
                       ${CMAKE_DL_LIBS})
 
 install (TARGETS gbe LIBRARY DESTINATION lib)
+install (FILES ocl_header.h.pch DESTINATION lib)
 install (FILES backend/program.h DESTINATION include/gen)
 
diff --git a/backend/src/backend/program.cpp b/backend/src/backend/program.cpp
index 2a4feb9..7f9b36b 100644
--- a/backend/src/backend/program.cpp
+++ b/backend/src/backend/program.cpp
@@ -35,6 +35,7 @@
 #include <cstring>
 #include <algorithm>
 #include <fstream>
+#include <dlfcn.h>
 
 /* Not defined for LLVM 3.0 */
 #if !defined(LLVM_VERSION_MAJOR)
@@ -222,25 +223,52 @@ namespace gbe {
 
   extern std::string ocl_stdlib_str;
   extern std::string ocl_common_defines_str;
+
   static gbe_program programNewFromSource(const char *source,
                                           size_t stringSize,
                                           const char *options,
                                           char *err,
                                           size_t *errSize)
   {
+    Dl_info info;
     char clStr[L_tmpnam+1], llStr[L_tmpnam+1];
     const std::string clName = std::string(tmpnam_r(clStr)) + ".cl"; /* unsafe! */
     const std::string llName = std::string(tmpnam_r(llStr)) + ".ll"; /* unsafe! */
+    std::string pchHeaderName;
+    std::string clOpt;
 
-    // Write the source to the cl file
     FILE *clFile = fopen(clName.c_str(), "w");
     FATAL_IF(clFile == NULL, "Failed to open temporary file");
-    fwrite(ocl_common_defines_str.c_str(), strlen(ocl_common_defines_str.c_str()), 1, clFile);
-    fwrite(ocl_stdlib_str.c_str(), strlen(ocl_stdlib_str.c_str()), 1, clFile);
+
+    if(options)
+      clOpt += options;
+
+    if (::strstr(options, "-cl-std")) {
+      /* Some building option may cause the prebuild pch header file
+         not compatible with the XXX.cl source. We need rebuild all here.*/
+      fwrite(ocl_common_defines_str.c_str(), strlen(ocl_common_defines_str.c_str()), 1, clFile);
+      fwrite(ocl_stdlib_str.c_str(), strlen(ocl_stdlib_str.c_str()), 1, clFile);         
+    } else {
+      /* Get the path of the shared lib of ourself, the pch file
+         always exists in the same folder. */
+      ::dladdr((const void*)programNewFromSource, &info);
+      llvm::StringRef str(info.dli_fname);
+      FATAL_IF(!str.endswith("libgbe.so"), "Failed to find the path of our lib self");
+      str = str.substr(0, str.rfind("/") + 1);
+
+      pchHeaderName = str.str();
+      pchHeaderName += "ocl_header.h.pch";
+      
+      clOpt += "-include-pch ";
+      clOpt += pchHeaderName;
+      clOpt += " ";
+    }
+
+    // Write the source to the cl file
     fwrite(source, strlen(source), 1, clFile);
     fclose(clFile);
 
-    buildModuleFromSource(clName.c_str(), llName.c_str(), options ? options : "");
+    buildModuleFromSource(clName.c_str(), llName.c_str(), clOpt.c_str());
     remove(clName.c_str());
 
     // Now build the program from llvm
-- 
1.7.9.5