[Beignet] [PATCH] GBE: Use addRemappedFile to avoid creating temporary cl source file.

[Zhigang Gong]

LLVM provides powerful string-remapped feature which could be used
to map a string to an input file name, thus we don't need to create
a temporary cl source file any more.

This patch not only make things much clear and avoid the unecessary
file creation. It only fixes some weird directory related problems.
Because beignet creates the temoprary file at the /tmp directory.
Then the clang will search the include files in that directory by
default, but the developer expects it to search the working directory
firstly. This causing two weird things:
1. If a .cl file is including a .h file in the current directory, beignet
   will not find it.

2. Even if the probram add a "-I." option manually, beignet will search /tmp
   firstly, and if there is a .h file in /tmp/ with the eaxct same file
   name, beignet will the file located in /tmp.

Signed-off-by: Zhigang Gong <zhigang.gong at intel.com>
---
 backend/src/backend/program.cpp | 40 ++++++++++------------------------------
 1 file changed, 10 insertions(+), 30 deletions(-)

diff --git a/backend/src/backend/program.cpp b/backend/src/backend/program.cpp
index d9e6416..330bead 100644
--- a/backend/src/backend/program.cpp
+++ b/backend/src/backend/program.cpp
@@ -518,7 +518,7 @@ namespace gbe {
 #ifdef GBE_COMPILER_AVAILABLE
   BVAR(OCL_OUTPUT_BUILD_LOG, false);
 
-  static bool buildModuleFromSource(const char* input, llvm::Module** out_module, llvm::LLVMContext* llvm_ctx,
+  static bool buildModuleFromSource(const char *source, llvm::Module** out_module, llvm::LLVMContext* llvm_ctx,
                                     std::string dumpLLVMFileName, std::vector<std::string>& options, size_t stringSize, char *err,
                                     size_t *errSize) {
     // Arguments to pass to the clang frontend
@@ -551,8 +551,7 @@ namespace gbe {
     args.push_back("-triple");
     args.push_back("spir");
 #endif /* LLVM_VERSION_MINOR <= 2 */
-    args.push_back(input);
-
+    args.push_back("stringInput.cl");
     args.push_back("-ffp-contract=off");
 
     // The compiler invocation needs a DiagnosticsEngine so it can report problems
@@ -574,6 +573,9 @@ namespace gbe {
                                               &args[0],
                                               &args[0] + args.size(),
                                               Diags);
+    llvm::StringRef srcString(source);
+    (*CI).getPreprocessorOpts().addRemappedFile("stringInput.cl",
+                llvm::MemoryBuffer::getMemBuffer(srcString).release());
 
     // Create the compiler instance
     clang::CompilerInstance Clang;
@@ -670,7 +672,6 @@ namespace gbe {
                                      std::vector<std::string>& clOpt,
                                      std::string& dumpLLVMFileName,
                                      std::string& dumpASMFileName,
-                                     std::string& clName,
                                      int& optLevel,
                                      size_t stringSize,
                                      char *err,
@@ -781,21 +782,6 @@ namespace gbe {
       }
     }
 
-    char clStr[] = "/tmp/XXXXXX.cl";
-    int clFd = mkstemps(clStr, 3);
-    clName = std::string(clStr);
-
-    FILE *clFile = fdopen(clFd, "w");
-    FATAL_IF(clFile == NULL, "Failed to open temporary file");
-    // XXX enable cl_khr_fp64 may cause some potential bugs.
-    // we may need to revisit here latter when we want to support fp64 completely.
-    // For now, as we don't support fp64 actually, just disable it by default.
-#if 0
-    #define ENABLE_CL_KHR_FP64_STR "#pragma OPENCL EXTENSION cl_khr_fp64 : enable\n"
-    if (options && !strstr(const_cast<char *>(options), "-cl-std=CL1.1"))
-      fwrite(ENABLE_CL_KHR_FP64_STR, strlen(ENABLE_CL_KHR_FP64_STR), 1, clFile);
-#endif
-
     if (!findPCH || invalidPCH) {
       clOpt.push_back("-include");
       clOpt.push_back("ocl.h");
@@ -805,9 +791,6 @@ namespace gbe {
       clOpt.push_back(pchFileName);
     }
 
-    // Write the source to the cl file
-    fwrite(source, strlen(source), 1, clFile);
-    fclose(clFile);
     return true;
   }
 
@@ -820,11 +803,10 @@ namespace gbe {
   {
     int optLevel = 1;
     std::vector<std::string> clOpt;
-    std::string clName;
     std::string dumpLLVMFileName, dumpASMFileName;
     if (!processSourceAndOption(source, options, NULL, clOpt,
                                 dumpLLVMFileName, dumpASMFileName,
-                                clName, optLevel,
+                                optLevel,
                                 stringSize, err, errSize))
       return NULL;
 
@@ -836,7 +818,7 @@ namespace gbe {
     if (!llvm::llvm_is_multithreaded())
       llvm_mutex.lock();
 
-    if (buildModuleFromSource(clName.c_str(), &out_module, llvm_ctx, dumpLLVMFileName, clOpt,
+    if (buildModuleFromSource(source, &out_module, llvm_ctx, dumpLLVMFileName, clOpt,
                               stringSize, err, errSize)) {
     // Now build the program from llvm
       size_t clangErrSize = 0;
@@ -862,7 +844,6 @@ namespace gbe {
     if (!llvm::llvm_is_multithreaded())
       llvm_mutex.unlock();
 
-    remove(clName.c_str());
     return p;
   }
 #endif
@@ -879,10 +860,9 @@ namespace gbe {
   {
     int optLevel = 1;
     std::vector<std::string> clOpt;
-    std::string clName;
     std::string dumpLLVMFileName, dumpASMFileName;
     if (!processSourceAndOption(source, options, temp_header_path, clOpt,
-                                dumpLLVMFileName, dumpASMFileName, clName,
+                                dumpLLVMFileName, dumpASMFileName,
                                 optLevel, stringSize, err, errSize))
       return NULL;
 
@@ -892,7 +872,8 @@ namespace gbe {
     //for some functions, so we use global context now, need switch to new context later.
     llvm::Module * out_module;
     llvm::LLVMContext* llvm_ctx = &llvm::getGlobalContext();
-    if (buildModuleFromSource(clName.c_str(), &out_module, llvm_ctx, dumpLLVMFileName, clOpt,
+
+    if (buildModuleFromSource(source, &out_module, llvm_ctx, dumpLLVMFileName, clOpt,
                               stringSize, err, errSize)) {
     // Now build the program from llvm
       if (err != NULL) {
@@ -907,7 +888,6 @@ namespace gbe {
         llvm::errs() << options;
     } else
       p = NULL;
-    remove(clName.c_str());
     releaseLLVMContextLock();
     return p;
   }
-- 
1.9.1