Refactor LLVM JIT (#1613)

Refactor LLVM JIT for some purposes:
- To simplify the source code of JIT compilation
- To simplify the JIT modes
- To align with LLVM latest changes
- To prepare for the Multi-tier JIT compilation, refer to #1302

The changes mainly include:
- Remove the MCJIT mode, replace it with ORC JIT eager mode
- Remove the LLVM legacy pass manager (only keep the LLVM new pass manager)
- Change the lazy mode's LLVM module/function binding:
  change each function in an individual LLVM module into all functions in a single LLVM module
- Upgraded ORC JIT to ORCv2 JIT to enable lazy compilation

Refer to #1468

core/iwasm/compilation/aot_llvm.h

@@ -20,20 +20,18 @@
 #include "llvm-c/Transforms/Vectorize.h"
 #include "llvm-c/Transforms/PassManagerBuilder.h"
 
-#if WASM_ENABLE_LAZY_JIT != 0
 #include "llvm-c/Orc.h"
 #include "llvm-c/Error.h"
 #include "llvm-c/Support.h"
 #include "llvm-c/Initialization.h"
 #include "llvm-c/TargetMachine.h"
-#if LLVM_VERSION_MAJOR >= 12
 #include "llvm-c/LLJIT.h"
-#endif
-#endif
 #if WASM_ENABLE_DEBUG_AOT != 0
 #include "llvm-c/DebugInfo.h"
 #endif
 
+#include "aot_orc_extra.h"
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -52,6 +50,16 @@ extern "C" {
 #define OPQ_PTR_TYPE INT8_PTR_TYPE
 #endif
 
+#ifndef NDEBUG
+#undef DEBUG_PASS
+#undef DUMP_MODULE
+// #define DEBUG_PASS
+// #define DUMP_MODULE
+#else
+#undef DEBUG_PASS
+#undef DUMP_MODULE
+#endif
+
 /**
  * Value in the WASM operation stack, each stack element
  * is an LLVM value
@@ -270,12 +278,6 @@ typedef struct AOTCompContext {
 
     /* LLVM variables required to emit LLVM IR */
     LLVMContextRef context;
-#if WASM_ENABLE_LAZY_JIT == 0
-    /* Create one module only for non LAZY JIT mode,
-       for LAZY JIT mode, modules are created, each
-       aot function has its own module */
-    LLVMModuleRef module;
-#endif
     LLVMBuilderRef builder;
 #if WASM_ENABLE_DEBUG_AOT
     LLVMDIBuilderRef debug_builder;
@@ -290,19 +292,11 @@ typedef struct AOTCompContext {
     /* Hardware intrinsic compability flags */
     uint64 flags[8];
 
-    /* LLVM execution engine required by JIT */
-#if WASM_ENABLE_LAZY_JIT != 0
-    LLVMOrcLLJITRef orc_lazyjit;
-    LLVMOrcMaterializationUnitRef orc_material_unit;
-    LLVMOrcLazyCallThroughManagerRef orc_call_through_mgr;
-    LLVMOrcIndirectStubsManagerRef orc_indirect_stub_mgr;
-    LLVMOrcCSymbolAliasMapPairs orc_symbol_map_pairs;
+    /* required by JIT */
+    LLVMOrcLLLazyJITRef orc_jit;
     LLVMOrcThreadSafeContextRef orc_thread_safe_context;
-    /* Each aot function has its own module */
-    LLVMModuleRef *modules;
-#else
-    LLVMExecutionEngineRef exec_engine;
-#endif
+
+    LLVMModuleRef module;
 
     bool is_jit_mode;
 
@@ -361,6 +355,7 @@ typedef struct AOTCompContext {
     AOTLLVMConsts llvm_consts;
 
     /* Function contexts */
+    /* TODO: */
     AOTFuncContext **func_ctxes;
     uint32 func_ctx_count;
     char **custom_sections_wp;
@@ -503,24 +498,11 @@ void
 aot_add_simple_loop_unswitch_pass(LLVMPassManagerRef pass);
 
 void
-aot_apply_llvm_new_pass_manager(AOTCompContext *comp_ctx);
-
-#if WASM_ENABLE_LAZY_JIT != 0
-LLVMOrcJITTargetMachineBuilderRef
-LLVMOrcJITTargetMachineBuilderCreateFromTargetMachine(LLVMTargetMachineRef TM);
-
-void
-LLVMOrcLLJITBuilderSetNumCompileThreads(LLVMOrcLLJITBuilderRef orcjit_builder,
-                                        unsigned num_compile_threads);
+aot_apply_llvm_new_pass_manager(AOTCompContext *comp_ctx, LLVMModuleRef module);
 
 void
 aot_handle_llvm_errmsg(const char *string, LLVMErrorRef err);
 
-void *
-aot_lookup_orcjit_func(LLVMOrcLLJITRef orc_lazyjit, void *module_inst,
-                       uint32 func_idx);
-#endif
-
 #ifdef __cplusplus
 } /* end of extern "C" */
 #endif