gallivm: orcjit: remember Context in addition to ThreadSafeContext

The llvm::orc::ThreadSafeContext object wraps an llvm::Context and keeps
its reference.

As we are no longer able to squeeze out Context from ThreadSafeContext
in LLVM 21, do not let ThreadSafeContext create Context implicitly for
LLVM 21, instead explicitly create Context and then remember it.

This also eliminates the code creating a Context that is never disposed.

Fixes: cd129dbf8a ("gallivm: support LLVM 21")
Signed-off-by: Icenowy Zheng <uwu@icenowy.me>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/37684>

src/gallium/auxiliary/gallivm/lp_bld.h

@@ -88,10 +88,9 @@
 #define LLVMCreateBuilder ILLEGAL_LLVM_FUNCTION
 
 typedef struct lp_context_ref {
-#if GALLIVM_USE_ORCJIT
-   LLVMOrcThreadSafeContextRef ref;
-#else
    LLVMContextRef ref;
+#if GALLIVM_USE_ORCJIT
+   LLVMOrcThreadSafeContextRef tsref;
 #endif
    bool owned;
 } lp_context_ref;
@@ -101,18 +100,21 @@ lp_context_create(lp_context_ref *context)
 {
    assert(context != NULL);
 #if GALLIVM_USE_ORCJIT
-   context->ref = LLVMOrcCreateNewThreadSafeContext();
+#if LLVM_VERSION_MAJOR >= 21
+   context->ref = LLVMContextCreate();
+   /* Ownership of ref is then transferred to tsref */
+   context->tsref = LLVMOrcCreateNewThreadSafeContextFromLLVMContext(context->ref);
+#else
+   context->tsref = LLVMOrcCreateNewThreadSafeContext();
+   context->ref = LLVMOrcThreadSafeContextGetContext(context->tsref);
+#endif
 #else
    context->ref = LLVMContextCreate();
 #endif
    context->owned = true;
 #if LLVM_VERSION_MAJOR == 15
    if (context->ref) {
-#if GALLIVM_USE_ORCJIT
-      LLVMContextSetOpaquePointers(LLVMOrcThreadSafeContextGetContext(context->ref), false);
-#else
       LLVMContextSetOpaquePointers(context->ref, false);
-#endif
    }
 #endif
 }
@@ -123,7 +125,7 @@ lp_context_destroy(lp_context_ref *context)
    assert(context != NULL);
    if (context->owned) {
 #if GALLIVM_USE_ORCJIT
-      LLVMOrcDisposeThreadSafeContext(context->ref);
+      LLVMOrcDisposeThreadSafeContext(context->tsref);
 #else
       LLVMContextDispose(context->ref);
 #endif

src/gallium/auxiliary/gallivm/lp_bld_init_orc.cpp

@@ -555,8 +555,8 @@ init_gallivm_state(struct gallivm_state *gallivm, const char *name,
 
    gallivm->cache = cache;
 
-   gallivm->_ts_context = context->ref;
-   gallivm->context = LLVMContextCreate();
+   gallivm->_ts_context = context->tsref;
+   gallivm->context = context->ref;
 
    gallivm->module_name = LPJit::get_unique_name(name);
    gallivm->module = LLVMModuleCreateWithNameInContext(gallivm->module_name,