GBE: remove static context to fix Segmentation fault.

If application has static clProgram, when application exit, the static
context has been deleted before delete static clProgram will cause
segmentation fault.
As the global static context is just for link, use the individual context
of each llvm module, when link the llvm module, generate the new llvm
module from src.

V2: fix llvm 3.8 build error and CleanLlvmResource delete bug.
Signed-off-by: Yang Rong <rong.r.yang@intel.com>
Reviewed-by: Ruiling Song <ruiling.song@intel.com>

4 files changed, 39 insertions, 33 deletions

diff --git a/backend/src/backend/gen_program.cpp b/backend/src/backend/gen_program.cpp
index 6ba2e549..e06ed40c 100644
--- a/backend/src/backend/gen_program.cpp
+++ b/backend/src/backend/gen_program.cpp
@@ -28,6 +28,8 @@
 #include "llvm/IR/Module.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm-c/Linker.h"
+#include "llvm-c/BitReader.h"
+#include "llvm-c/BitWriter.h"
 #include "llvm/Transforms/Utils/Cloning.h"
 #if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 40
 #include "llvm/Bitcode/BitcodeWriter.h"
@@ -126,16 +128,25 @@ namespace gbe {
 
   void GenProgram::CleanLlvmResource(void){
 #ifdef GBE_COMPILER_AVAILABLE
+    llvm::LLVMContext* ctx = NULL;
     if(module){
+      ctx = &((llvm::Module*)module)->getContext();
+      (void)ctx;
       delete (llvm::Module*)module;
       module = NULL;
     }
-
+//llvm's version < 3.9, ctx is global ctx, can't be deleted.
+#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 39
+    //each module's context is individual, just delete it, ignaor llvm_ctx.
+    if (ctx != NULL)
+      delete ctx;
+#else
     if(llvm_ctx){
       delete (llvm::LLVMContext*)llvm_ctx;
       llvm_ctx = NULL;
     }
 #endif
+#endif
   }
 
   /*! We must avoid spilling at all cost with Gen */
@@ -353,19 +364,19 @@ 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 = new llvm::LLVMContext;
 #else
-    llvm::LLVMContext& c = llvm::getGlobalContext();
+    llvm::LLVMContext *c = &llvm::getGlobalContext();
 #endif
     llvm::SMDiagnostic Err;
 #if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 36
     std::unique_ptr<llvm::MemoryBuffer> memory_buffer = llvm::MemoryBuffer::getMemBuffer(llvm_bin_str, "llvm_bin_str");
     acquireLLVMContextLock();
-    llvm::Module* module = llvm::parseIR(memory_buffer->getMemBufferRef(), Err, c).release();
+    llvm::Module* module = llvm::parseIR(memory_buffer->getMemBufferRef(), Err, *c).release();
 #else
     llvm::MemoryBuffer* memory_buffer = llvm::MemoryBuffer::getMemBuffer(llvm_bin_str, "llvm_bin_str");
     acquireLLVMContextLock();
-    llvm::Module* module = llvm::ParseIR(memory_buffer, Err, c);
+    llvm::Module* module = llvm::ParseIR(memory_buffer, Err, *c);
 #endif
     // if load 32 bit spir binary, the triple should be spir-unknown-unknown.
     llvm::Triple triple(module->getTargetTriple());
@@ -506,23 +517,31 @@ namespace gbe {
     using namespace gbe;
     char* errMsg = NULL;
     if(((GenProgram*)dst_program)->module == NULL){
-#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 38
+#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 39
+      LLVMModuleRef modRef;
+      LLVMParseBitcodeInContext2(wrap(new llvm::LLVMContext()),
+                                 LLVMWriteBitcodeToMemoryBuffer(wrap((llvm::Module*)((GenProgram*)src_program)->module)),
+                                 &modRef);
+      ((GenProgram*)dst_program)->module = llvm::unwrap(modRef);
+#elif LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 38
       ((GenProgram*)dst_program)->module = llvm::CloneModule((llvm::Module*)((GenProgram*)src_program)->module).release();
 #else
       ((GenProgram*)dst_program)->module = llvm::CloneModule((llvm::Module*)((GenProgram*)src_program)->module);
 #endif
       errSize = 0;
     } else {
-#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 39
-      // Src now will be removed automatically. So clone it.
-      llvm::Module* src = llvm::CloneModule((llvm::Module*)((GenProgram*)src_program)->module).release();
-#else
       llvm::Module* src = (llvm::Module*)((GenProgram*)src_program)->module;
-#endif
       llvm::Module* dst = (llvm::Module*)((GenProgram*)dst_program)->module;
-
 #if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 39
-      if (LLVMLinkModules2(wrap(dst), wrap(src))) {
+      if (&src->getContext() != &dst->getContext()) {
+        LLVMModuleRef modRef;
+        LLVMParseBitcodeInContext2(wrap(&dst->getContext()),
+                                    LLVMWriteBitcodeToMemoryBuffer(wrap(src)),
+                                    &modRef);
+        src = llvm::unwrap(modRef);
+      }
+      llvm::Module* clone = llvm::CloneModule(src).release();
+      if (LLVMLinkModules2(wrap(dst), wrap(clone))) {
 #elif LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 37
       if (LLVMLinkModules(wrap(dst), wrap(src), LLVMLinkerPreserveSource_Removed, &errMsg)) {
 #else
@@ -536,7 +555,6 @@ namespace gbe {
         return true;
       }
     }
-    // Everything run fine
 #endif
     return false;
   }
diff --git a/backend/src/backend/program.cpp b/backend/src/backend/program.cpp
index c06ae5a1..c37c5951 100644
--- a/backend/src/backend/program.cpp
+++ b/backend/src/backend/program.cpp
@@ -1104,22 +1104,22 @@ EXTEND_QUOTE:
       return NULL;
 
 #if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 39
-    llvm::LLVMContext& c = GBEGetLLVMContext();
+    llvm::LLVMContext *c = new llvm::LLVMContext;
 #else
-    llvm::LLVMContext& c = llvm::getGlobalContext();
+    llvm::LLVMContext *c = &llvm::getGlobalContext();
 #endif
     // Get the module from its file
     llvm::SMDiagnostic errDiag;
 #if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 36
-    llvm::Module *module = parseIRFile(fileName, errDiag, c).release();
+    llvm::Module *module = parseIRFile(fileName, errDiag, *c).release();
 #else
-    llvm::Module *module = ParseIRFile(fileName, errDiag, c);
+    llvm::Module *module = ParseIRFile(fileName, errDiag, *c);
 #endif
 
     int optLevel = 1;
 
     //module will be delete in programCleanLlvmResource
-    p = gbe_program_new_from_llvm(deviceID, module, &c, NULL,
+    p = gbe_program_new_from_llvm(deviceID, module, c, NULL,
                                   string_size, err, err_size, optLevel, NULL);
     if (OCL_OUTPUT_BUILD_LOG && err && *err_size)
       llvm::errs() << err << "\n";
@@ -1152,11 +1152,10 @@ EXTEND_QUOTE:
 
     gbe_program p;
     acquireLLVMContextLock();
-    //FIXME: if use new allocated context to link two modules there would be context mismatch
-    //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 = new llvm::LLVMContext;
 #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 8546f730..7f7deffe 100644
--- a/backend/src/llvm/llvm_to_gen.cpp
+++ b/backend/src/llvm/llvm_to_gen.cpp
@@ -46,13 +46,6 @@ namespace gbe
   BVAR(OCL_OUTPUT_CFG_GEN_IR, false);
   using namespace llvm;
 
-#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 39
-  llvm::LLVMContext& GBEGetLLVMContext() {
-    static llvm::LLVMContext GBEContext;
-    return GBEContext;
-  }
-#endif
-
 #if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 37
   #define TARGETLIBRARY  TargetLibraryInfoImpl
 #else
diff --git a/backend/src/llvm/llvm_to_gen.hpp b/backend/src/llvm/llvm_to_gen.hpp
index 73e88194..d2247bbf 100644
--- a/backend/src/llvm/llvm_to_gen.hpp
+++ b/backend/src/llvm/llvm_to_gen.hpp
@@ -37,10 +37,6 @@ namespace gbe {
 		  optLevel 0 equal to clang -O1 and 1 equal to clang -O2*/
   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();
-#endif
-
 } /* namespace gbe */
 
 #endif /* __GBE_IR_LLVM_TO_GEN_HPP__ */