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 <jfonseca@vmware.com>
Signed-off-by: Mathias Froehlich <Mathias.Froehlich@web.de>

src/gallium/auxiliary/draw/draw_llvm.c

@@ -493,6 +493,10 @@ draw_llvm_create(struct draw_context *draw)
 
    llvm->draw = draw;
 
+   llvm->context = LLVMContextCreate();
+   if (!llvm->context)
+      goto fail;
+
    llvm->nr_variants = 0;
    make_empty_list(&llvm->vs_variants_list);
 
@@ -500,6 +504,10 @@ draw_llvm_create(struct draw_context *draw)
    make_empty_list(&llvm->gs_variants_list);
 
    return llvm;
+
+fail:
+   draw_llvm_destroy(llvm);
+   return NULL;
 }
 
 
@@ -509,6 +517,9 @@ draw_llvm_create(struct draw_context *draw)
 void
 draw_llvm_destroy(struct draw_llvm *llvm)
 {
+   LLVMContextDispose(llvm->context);
+   llvm->context = NULL;
+
    /* XXX free other draw_llvm data? */
    FREE(llvm);
 }
@@ -540,7 +551,7 @@ draw_llvm_create_variant(struct draw_llvm *llvm,
    util_snprintf(module_name, sizeof(module_name), "draw_llvm_vs_variant%u",
                  variant->shader->variants_cached);
 
-   variant->gallivm = gallivm_create(module_name);
+   variant->gallivm = gallivm_create(module_name, llvm->context);
 
    create_jit_types(variant);
 
@@ -2195,7 +2206,7 @@ draw_gs_llvm_create_variant(struct draw_llvm *llvm,
    util_snprintf(module_name, sizeof(module_name), "draw_llvm_gs_variant%u",
                  variant->shader->variants_cached);
 
-   variant->gallivm = gallivm_create(module_name);
+   variant->gallivm = gallivm_create(module_name, llvm->context);
 
    create_gs_jit_types(variant);
 

src/gallium/auxiliary/draw/draw_llvm.h

@@ -461,6 +461,8 @@ struct llvm_geometry_shader {
 struct draw_llvm {
    struct draw_context *draw;
 
+   LLVMContextRef context;
+
    struct draw_jit_context jit_context;
    struct draw_gs_jit_context gs_jit_context;
 

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)
+   /* The LLVMContext should be owned by the parent of gallivm. */
-      LLVMContextDispose(gallivm->context);
 
    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 = context;
-      gallivm->context = LLVMGetGlobalContext();
+
-   } else {
-      gallivm->context = LLVMContextCreate();
-   }
    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;
       }

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);

src/gallium/drivers/llvmpipe/lp_context.c

@@ -93,6 +93,9 @@ static void llvmpipe_destroy( struct pipe_context *pipe )
 
    lp_delete_setup_variants(llvmpipe);
 
+   LLVMContextDispose(llvmpipe->context);
+   llvmpipe->context = NULL;
+
    align_free( llvmpipe );
 }
 
@@ -161,6 +164,10 @@ llvmpipe_create_context( struct pipe_screen *screen, void *priv )
    llvmpipe_init_context_resource_funcs( &llvmpipe->pipe );
    llvmpipe_init_surface_functions(llvmpipe);
 
+   llvmpipe->context = LLVMContextCreate();
+   if (!llvmpipe->context)
+      goto fail;
+
    /*
     * Create drawing context and plug our rendering stage into it.
     */

src/gallium/drivers/llvmpipe/lp_context.h

@@ -153,6 +153,9 @@ struct llvmpipe_context {
    struct pipe_query *render_cond_query;
    uint render_cond_mode;
    boolean render_cond_cond;
+
+   /** The LLVMContext to use for LLVM related work */
+   LLVMContextRef context;
 };
 
 

src/gallium/drivers/llvmpipe/lp_state_fs.c

@@ -2565,7 +2565,7 @@ generate_variant(struct llvmpipe_context *lp,
    util_snprintf(module_name, sizeof(module_name), "fs%u_variant%u",
                  shader->no, shader->variants_created);
 
-   variant->gallivm = gallivm_create(module_name);
+   variant->gallivm = gallivm_create(module_name, lp->context);
    if (!variant->gallivm) {
       FREE(variant);
       return NULL;

src/gallium/drivers/llvmpipe/lp_state_setup.c

@@ -731,7 +731,7 @@ generate_setup_variant(struct lp_setup_variant_key *key,
    util_snprintf(func_name, sizeof(func_name), "setup_variant_%u",
                  variant->no);
 
-   variant->gallivm = gallivm = gallivm_create(func_name);
+   variant->gallivm = gallivm = gallivm_create(func_name, lp->context);
    if (!variant->gallivm) {
       goto fail;
    }

src/gallium/drivers/llvmpipe/lp_test_arit.c

@@ -354,7 +354,7 @@ test_unary(unsigned verbose, FILE *fp, const struct unary_test_t *test)
       in[i] = 1.0;
    }
 
-   gallivm = gallivm_create("test_module");
+   gallivm = gallivm_create("test_module", LLVMGetGlobalContext());
 
    test_func = build_unary_test_func(gallivm, test);
 

src/gallium/drivers/llvmpipe/lp_test_blend.c

@@ -450,7 +450,7 @@ test_one(unsigned verbose,
    if(verbose >= 1)
       dump_blend_type(stdout, blend, type);
 
-   gallivm = gallivm_create("test_module");
+   gallivm = gallivm_create("test_module", LLVMGetGlobalContext());
 
    func = add_blend_test(gallivm, blend, type);
 

src/gallium/drivers/llvmpipe/lp_test_conv.c

@@ -211,7 +211,7 @@ test_one(unsigned verbose,
 
    eps = MAX2(lp_const_eps(src_type), lp_const_eps(dst_type));
 
-   gallivm = gallivm_create("test_module");
+   gallivm = gallivm_create("test_module", LLVMGetGlobalContext());
 
    func = add_conv_test(gallivm, src_type, num_srcs, dst_type, num_dsts);
 

src/gallium/drivers/llvmpipe/lp_test_format.c

@@ -138,7 +138,7 @@ test_format_float(unsigned verbose, FILE *fp,
    boolean success = TRUE;
    unsigned i, j, k, l;
 
-   gallivm = gallivm_create("test_module_float");
+   gallivm = gallivm_create("test_module_float", LLVMGetGlobalContext());
 
    fetch = add_fetch_rgba_test(gallivm, verbose, desc, lp_float32_vec4_type());
 

src/gallium/drivers/llvmpipe/lp_test_printf.c

@@ -94,7 +94,7 @@ test_printf(unsigned verbose, FILE *fp,
    test_printf_t test_printf_func;
    boolean success = TRUE;
 
-   gallivm = gallivm_create("test_module");
+   gallivm = gallivm_create("test_module", LLVMGetGlobalContext());
 
    test = add_printf_test(gallivm);