Update LLVM to 21.1.2.

Wraps the LLVMContext construction in LLVM 21 version check; LLVM 21 makes a
breaking change in LLVMContext construction, but WAMR still needs to
support older LLVM versions, e.g. for xtensa/esp32 support which is only
available in at most LLVM 19.

Author: wffurr

build-scripts/build_llvm.py

@@ -294,17 +294,17 @@ def main():
         "arc": {
             "repo": "https://github.com/llvm/llvm-project.git",
             "repo_ssh": "[email protected]:llvm/llvm-project.git",
-            "branch": "release/18.x",
+            "branch": "release/21.x",
         },
         "xtensa": {
             "repo": "https://github.com/espressif/llvm-project.git",
             "repo_ssh": "[email protected]:espressif/llvm-project.git",
-            "branch": "xtensa_release_18.1.2",
+            "branch": "xtensa_release_21.1.2",
         },
         "default": {
             "repo": "https://github.com/llvm/llvm-project.git",
             "repo_ssh": "[email protected]:llvm/llvm-project.git",
-            "branch": "release/18.x",
+            "branch": "release/21.x",
         },
     }
 

core/iwasm/compilation/aot_llvm.c

@@ -2656,18 +2656,21 @@ aot_create_comp_context(const AOTCompData *comp_data, aot_comp_option_t option)
     comp_ctx->comp_data = comp_data;
 
     /* Create LLVM context, module and builder */
-    comp_ctx->orc_thread_safe_context = LLVMOrcCreateNewThreadSafeContext();
-    if (!comp_ctx->orc_thread_safe_context) {
-        aot_set_last_error("create LLVM ThreadSafeContext failed.");
+    /* Construct an LLVMContext directly, note:
+       different from non LAZY JIT mode, no need to dispose this context, if
+       will be disposed when the thread safe context is disposed */
+    comp_ctx->context = LLVMContextCreate();
+    if (!comp_ctx->context) {
+        aot_set_last_error("create LLVM Context failed.");
         goto fail;
     }
 
-    /* Get a reference to the underlying LLVMContext, note:
-         different from non LAZY JIT mode, no need to dispose this context,
-         if will be disposed when the thread safe context is disposed */
-    if (!(comp_ctx->context = LLVMOrcThreadSafeContextGetContext(
-              comp_ctx->orc_thread_safe_context))) {
-        aot_set_last_error("get context from LLVM ThreadSafeContext failed.");
+    /* Wrap the LLVM context in a thread safe context. */
+    comp_ctx->orc_thread_safe_context =
+        LLVMOrcCreateNewThreadSafeContextFromLLVMContext(comp_ctx->context);
+    if (!comp_ctx->orc_thread_safe_context) {
+        aot_set_last_error(
+            "Create LLVM ThreadSafeContext from LLVMContext failed.");
         goto fail;
     }