[Beignet] [PATCH] GBE: Fix a assert in CleanLlvmResource.

[Yang Rong]

From: Zhu Bingbing <bingbingx.zhu at intel.com>

After llvm3.9, the global context is a static variable. When call
CleanLlvmResource, this global context may has been deleted. When
delete the context, the module been deleted. So check the context
before delete module.

Signed-off-by: Yang Rong <rong.r.yang at intel.com>
---
 backend/src/backend/gen_program.cpp |  8 +++++++-
 backend/src/backend/program.cpp     |  4 ++--
 backend/src/llvm/llvm_to_gen.cpp    | 15 +++++++++++++--
 backend/src/llvm/llvm_to_gen.hpp    |  2 +-
 4 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/backend/src/backend/gen_program.cpp b/backend/src/backend/gen_program.cpp
index bb1d22f..e7a88b4 100644
--- a/backend/src/backend/gen_program.cpp
+++ b/backend/src/backend/gen_program.cpp
@@ -126,6 +126,12 @@ namespace gbe {
 
   void GenProgram::CleanLlvmResource(void){
 #ifdef GBE_COMPILER_AVAILABLE
+#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 39
+    llvm::LLVMContext* c = GBEGetLLVMContext();
+    //context has been deleted, the module instantiated in the context
+    //also been deleted when delete context.
+    if (c == NULL) return;
+#endif
     if(module){
       delete (llvm::Module*)module;
       module = NULL;
@@ -353,7 +359,7 @@ namespace gbe {
     binary_content.assign(binary+1, size-1);
     llvm::StringRef llvm_bin_str(binary_content);
 #if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 39
-    llvm::LLVMContext& c = GBEGetLLVMContext();
+    llvm::LLVMContext& c = *GBEGetLLVMContext();
 #else
     llvm::LLVMContext& c = llvm::getGlobalContext();
 #endif
diff --git a/backend/src/backend/program.cpp b/backend/src/backend/program.cpp
index c06ae5a..fda2b33 100644
--- a/backend/src/backend/program.cpp
+++ b/backend/src/backend/program.cpp
@@ -1104,7 +1104,7 @@ EXTEND_QUOTE:
       return NULL;
 
 #if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 39
-    llvm::LLVMContext& c = GBEGetLLVMContext();
+    llvm::LLVMContext& c = *GBEGetLLVMContext();
 #else
     llvm::LLVMContext& c = llvm::getGlobalContext();
 #endif
@@ -1156,7 +1156,7 @@ EXTEND_QUOTE:
     //for some functions, so we use global context now, need switch to new context later.
     llvm::Module * out_module;
 #if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 39
-    llvm::LLVMContext* llvm_ctx = &GBEGetLLVMContext();
+    llvm::LLVMContext* llvm_ctx = GBEGetLLVMContext();
 #else
     llvm::LLVMContext* llvm_ctx = &llvm::getGlobalContext();
 #endif
diff --git a/backend/src/llvm/llvm_to_gen.cpp b/backend/src/llvm/llvm_to_gen.cpp
index 8546f73..a155459 100644
--- a/backend/src/llvm/llvm_to_gen.cpp
+++ b/backend/src/llvm/llvm_to_gen.cpp
@@ -47,8 +47,19 @@ namespace gbe
   using namespace llvm;
 
 #if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 39
-  llvm::LLVMContext& GBEGetLLVMContext() {
-    static llvm::LLVMContext GBEContext;
+  llvm::LLVMContext *GBEContext = NULL;
+  bool initialized = false;
+
+  void destroyLLVMContext (void) {
+    delete GBEContext;
+    GBEContext = NULL;
+  }
+  llvm::LLVMContext* GBEGetLLVMContext() {
+    if (initialized == false) {
+      GBEContext = new llvm::LLVMContext();
+      atexit(destroyLLVMContext);
+      initialized = true;
+    }
     return GBEContext;
   }
 #endif
diff --git a/backend/src/llvm/llvm_to_gen.hpp b/backend/src/llvm/llvm_to_gen.hpp
index 73e8819..56b8619 100644
--- a/backend/src/llvm/llvm_to_gen.hpp
+++ b/backend/src/llvm/llvm_to_gen.hpp
@@ -38,7 +38,7 @@ namespace gbe {
   bool llvmToGen(ir::Unit &unit, const void* module,
                  int optLevel, bool strictMath, int profiling, std::string &errors);
 #if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 39
-  extern llvm::LLVMContext& GBEGetLLVMContext();
+  extern llvm::LLVMContext* GBEGetLLVMContext();
 #endif
 
 } /* namespace gbe */
-- 
2.1.4