llvmpipe: Use two LLVMContexts per OpenGL context instead of a global one.

This is one step to make llvmpipe thread safe as mandated by the OpenGL
standard. Using the global LLVMContext is obviously a problem for
that kind of use pattern. The patch introduces two LLVMContext
instances that are private to an OpenGL context and used for all
compiles. One is put into struct draw_llvm and the other
one into struct llvmpipe_context.

Reviewed-by: Jose Fonseca <[email protected]>
Signed-off-by: Mathias Froehlich <[email protected]>

2 files changed, 8 insertions, 22 deletions

diff --git a/src/gallium/auxiliary/gallivm/lp_bld_init.c b/src/gallium/auxiliary/gallivm/lp_bld_init.c
index 75ef935eb22..8a484978f1e 100644
--- a/src/gallium/auxiliary/gallivm/lp_bld_init.c
+++ b/src/gallium/auxiliary/gallivm/lp_bld_init.c
@@ -78,17 +78,6 @@
 void LLVMLinkInMCJIT();
 #endif
 
-/*
- * LLVM has several global caches which pointing/derived from objects
- * owned by the context, so if we freeing contexts causes
- * memory leaks and false cache hits when these objects are destroyed.
- *
- * TODO: For thread safety on multi-threaded OpenGL we should use one LLVM
- * context per thread, and put them in a pool when threads are destroyed.
- */
-#define USE_GLOBAL_CONTEXT 1
-
-
 #ifdef DEBUG
 unsigned gallivm_debug = 0;
 
@@ -209,8 +198,7 @@ gallivm_free_ir(struct gallivm_state *gallivm)
    if (gallivm->builder)
       LLVMDisposeBuilder(gallivm->builder);
 
-   if (!USE_GLOBAL_CONTEXT && gallivm->context)
-      LLVMContextDispose(gallivm->context);
+   /* The LLVMContext should be owned by the parent of gallivm. */
 
    gallivm->engine = NULL;
    gallivm->target = NULL;
@@ -301,7 +289,8 @@ fail:
  * \return  TRUE for success, FALSE for failure
  */
 static boolean
-init_gallivm_state(struct gallivm_state *gallivm, const char *name)
+init_gallivm_state(struct gallivm_state *gallivm, const char *name,
+                   LLVMContextRef context)
 {
    assert(!gallivm->context);
    assert(!gallivm->module);
@@ -309,11 +298,8 @@ init_gallivm_state(struct gallivm_state *gallivm, const char *name)
    if (!lp_build_init())
       return FALSE;
 
-   if (USE_GLOBAL_CONTEXT) {
-      gallivm->context = LLVMGetGlobalContext();
-   } else {
-      gallivm->context = LLVMContextCreate();
-   }
+   gallivm->context = context;
+
    if (!gallivm->context)
       goto fail;
 
@@ -495,13 +481,13 @@ lp_build_init(void)
  * Create a new gallivm_state object.
  */
 struct gallivm_state *
-gallivm_create(const char *name)
+gallivm_create(const char *name, LLVMContextRef context)
 {
    struct gallivm_state *gallivm;
 
    gallivm = CALLOC_STRUCT(gallivm_state);
    if (gallivm) {
-      if (!init_gallivm_state(gallivm, name)) {
+      if (!init_gallivm_state(gallivm, name, context)) {
          FREE(gallivm);
          gallivm = NULL;
       }
diff --git a/src/gallium/auxiliary/gallivm/lp_bld_init.h b/src/gallium/auxiliary/gallivm/lp_bld_init.h
index 64c5278c24e..6e9f52554a3 100644
--- a/src/gallium/auxiliary/gallivm/lp_bld_init.h
+++ b/src/gallium/auxiliary/gallivm/lp_bld_init.h
@@ -54,7 +54,7 @@ lp_build_init(void);
 
 
 struct gallivm_state *
-gallivm_create(const char *name);
+gallivm_create(const char *name, LLVMContextRef context);
 
 void
 gallivm_destroy(struct gallivm_state *gallivm);