From be71bbfaa2ad201b570b56847a13328fc359d0ee Mon Sep 17 00:00:00 2001 From: Brian Paul Date: Fri, 15 May 2015 09:08:14 -0600 Subject: [PATCH] mesa: do not use _glapi_new_nop_table() for DRI builds Commit 4bdbb588a9d38 introduced new _glapi_new_nop_table() and _glapi_set_nop_handler() functions in the glapi dispatcher (which live in libGL.so). The calls to those functions from context.c would be undefined (i.e. an ABI break) if the libGL used at runtime was older. For the time being, use the old single generic_nop() function for non-Windows builds to avoid this problem. At some point in the future it should be safe to remove this work-around. See comments for more details. v2: Incorporate feedback from Emil. Use _WIN32 instead of GLX_DIRECT_RENDERING to control behavior, move comments. Cc: 10.6 Reviewed-and-tested-by: Ian Romanick --- src/mesa/main/context.c | 62 +++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 60 insertions(+), 2 deletions(-) diff --git a/src/mesa/main/context.c b/src/mesa/main/context.c index 544cc14..02875ba 100644 --- a/src/mesa/main/context.c +++ b/src/mesa/main/context.c @@ -883,6 +883,19 @@ update_default_objects(struct gl_context *ctx) } +/* XXX this is temporary and should be removed at some point in the + * future when there's a reasonable expectation that the libGL library + * contains the _glapi_new_nop_table() and _glapi_set_nop_handler() + * functions which were added in Mesa 10.6. + */ +#if !defined(_WIN32) +/* Avoid libGL / driver ABI break */ +#define USE_GLAPI_NOP_FEATURES 0 +#else +#define USE_GLAPI_NOP_FEATURES 1 +#endif + + /** * This function is called by the glapi no-op functions. For each OpenGL * function/entrypoint there's a simple no-op function. These "no-op" @@ -898,6 +911,7 @@ update_default_objects(struct gl_context *ctx) * * \param name the name of the OpenGL function */ +#if USE_GLAPI_NOP_FEATURES static void nop_handler(const char *name) { @@ -914,6 +928,7 @@ nop_handler(const char *name) } #endif } +#endif /** @@ -923,7 +938,45 @@ nop_handler(const char *name) static void GLAPIENTRY nop_glFlush(void) { - /* don't record an error like we do in _mesa_generic_nop() */ + /* don't record an error like we do in nop_handler() */ +} +#endif + + +#if !USE_GLAPI_NOP_FEATURES +static int +generic_nop(void) +{ + GET_CURRENT_CONTEXT(ctx); + _mesa_error(ctx, GL_INVALID_OPERATION, + "unsupported function called " + "(unsupported extension or deprecated function?)"); + return 0; +} +#endif + + +/** + * Create a new API dispatch table in which all entries point to the + * generic_nop() function. This will not work on Windows because of + * the __stdcall convention which requires the callee to clean up the + * call stack. That's impossible with one generic no-op function. + */ +#if !USE_GLAPI_NOP_FEATURES +static struct _glapi_table * +new_nop_table(unsigned numEntries) +{ + struct _glapi_table *table; + + table = malloc(numEntries * sizeof(_glapi_proc)); + if (table) { + _glapi_proc *entry = (_glapi_proc *) table; + unsigned i; + for (i = 0; i < numEntries; i++) { + entry[i] = (_glapi_proc) generic_nop; + } + } + return table; } #endif @@ -941,7 +994,11 @@ alloc_dispatch_table(void) * Mesa we do this to accommodate different versions of libGL and various * DRI drivers. */ - GLint numEntries = MAX2(_glapi_get_dispatch_table_size(), _gloffset_COUNT); + int numEntries = MAX2(_glapi_get_dispatch_table_size(), _gloffset_COUNT); + +#if !USE_GLAPI_NOP_FEATURES + struct _glapi_table *table = new_nop_table(numEntries); +#else struct _glapi_table *table = _glapi_new_nop_table(numEntries); #if defined(_WIN32) @@ -967,6 +1024,7 @@ alloc_dispatch_table(void) #endif _glapi_set_nop_handler(nop_handler); +#endif return table; } -- 2.7.4