The previous implementation was dereferencing the sample pointer in
order to get the offset to subtract from the member pointer. The
resulting value is then only used to get a pointer to the member in
order to calculate the offset so it doesn't actually read from the
memory location and shouldn't cause any problems. However this is
probably technically invalid and could have undefined behaviour. It
looks like clang takes advantage of this undefined behaviour and
doesn't actually offset the pointer. It also generates a warning when
it does this.
This patch splits the _cogl_container_of macro into two
implementations. Previously the macro was always used in the list
iterator macros like this:
SomeType *sample = _cogl_container_of(list_node, sample, link)
Instead of doing that there is now a new macro called
_cogl_list_set_iterator which explicitly assigns to the sample pointer
with an initial value before assigning to it again with the real
offset. This redundant initialisation gets optimised out by compiler.
The second macro is still called _cogl_container_of but instead of
taking a sample pointer it just directly takes the type name. That way
it can use the standard offsetof macro.
https://bugzilla.gnome.org/show_bug.cgi?id=723530
Reviewed-by: Robert Bragg <robert@linux.intel.com>
(cherry picked from commit 1efed1e0a2bce706eb4901979ed4e717bb13e4e2)
This removes cogl-queue.h and adds a copy of Wayland's embedded list
implementation. The advantage of the Wayland model is that it is much
simpler and so it is easier to follow. It also doesn't require
defining a typedef for every list type.
The downside is that there is only one list type which is a
doubly-linked list where the head has a pointer to both the beginning
and the end. The BSD implementation has many more combinations some of
which we were taking advantage of to reduce the size of critical
structs where we didn't need a pointer to the end of the list.
The corresponding changes to uses of cogl-queue.h are:
• COGL_STAILQ_* was used for onscreen the list of events and dirty
notifications. This makes the size of the CoglContext grow by one
pointer.
• COGL_TAILQ_* was used for fences.
• COGL_LIST_* for CoglClosures. In this case the list head now has an
extra pointer which means CoglOnscreen will grow by the size of
three pointers, but this doesn't seem like a particularly important
struct to optimise for size anyway.
• COGL_LIST_* was used for the list of foreign GLES2 offscreens.
• COGL_TAILQ_* was used for the list of sub stacks in a
CoglMemoryStack.
• COGL_LIST_* was used to track the list of layers that haven't had
code generated yet while generating a fragment shader for a
pipeline.
• COGL_LIST_* was used to track the pipeline hierarchy in CoglNode.
The last part is a bit more controversial because it increases the
size of CoglPipeline and CoglPipelineLayer by one pointer in order to
have the redundant tail pointer for the list head. Normally we try to
be very careful about the size of the CoglPipeline struct. Because
CoglPipeline is slice-allocated, this effectively ends up adding two
pointers to the size because GSlice rounds up to the size of two
pointers.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
(cherry picked from commit 13abf613b15f571ba1fcf6d2eb831ffc6fa31324)
Conflicts:
cogl/cogl-context-private.h
cogl/cogl-context.c
cogl/driver/gl/cogl-pipeline-fragend-glsl.c
doc/reference/cogl-2.0-experimental/Makefile.am
This fixes _cogl_memory_stack_free to ensure we don't dereference freed
memory as we iterate the sub-stacks to free them.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
(cherry picked from commit 1d27fedef9c599aa9976b809f18e0da1913cec26)
CoglMemoryStack was being typedef'd twice, once in the private header
as an incomplete struct and once in the C source with the actual
struct definition. This removes the second typedef so that it just
defines the struct.
This patch was written by Jack River.
https://bugzilla.gnome.org/show_bug.cgi?id=675119
Reviewed-by: Neil Roberts <neil@linux.intel.com>
(cherry picked from commit 75cd425a48e0fc403bf88eace212a6d37b65df11)
This adds a very minimal internal allocator api that lets us create a
dynamically growable (grow only) stack.
Underlying the allocator is the idea of "sub stacks" which are simply
malloc()'d chunks of memory kept in a linked list. The stack itself
maintains a pointer to the current sub-stack and a current
sub-stack-offset. 99% of the time allocating from the stack is just a
case of returning a pointer to the current sub-stack + sub-stack-offset
and bumping the offset by the allocation size. If there isn't room in
the current sub-stack then we walk through the list of free sub-stacks
looking for one that's big enough for the allocation and if we reach the
end of the list then we allocate a new sub-stack twice as big as the
last (or twice as big as the requested allocation if that's bigger).
Since it's a stack model there is no api to free allocations, just a
function to rewind the stack to the beginning.
We expect this to be useful in multiple places in Cogl as an extremely
fast allocator in cases when we know we can scrap all the allocations
after we're done figuring something out or as a building block for
other allocators.
For example the tessellator used for CoglPath allocates lots of tiny
structures that can all be freed after tessellation.
Reviewed-by: Neil Roberts <neil@linux.intel.com>
(cherry picked from commit 6ee4a7a1b7f695bdfeb10ffa4112e776beea0a9d)
