<div dir="ltr"> <div class="gmail_extra"> <div class="gmail_quote">On Wed, Apr 13, 2016 at 12:15 PM, Connor Abbott <<a href="mailto:cwabbott0@gmail.com" target="_blank">cwabbott0@gmail.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="HOEnZb"><div class="h5">On Wed, Apr 13, 2016 at 2:49 PM, Jason Ekstrand <<a href="mailto:jason@jlekstrand.net">jason@jlekstrand.net</a>> wrote: > > > On Wed, Apr 13, 2016 at 8:15 AM, Jason Ekstrand <<a href="mailto:jason@jlekstrand.net">jason@jlekstrand.net</a>> > wrote: >> >> >> On Apr 13, 2016 4:57 AM, "Rob Clark" <<a href="mailto:robdclark@gmail.com">robdclark@gmail.com</a>> wrote: >> > >> > On Wed, Apr 13, 2016 at 12:34 AM, Connor Abbott <<a href="mailto:cwabbott0@gmail.com">cwabbott0@gmail.com</a>> >> > wrote: >> > > Previously, these were functions which took a callback. This meant >> > > that >> > > the per-block code had to be in a separate function, and all the data >> > > that you wanted to pass in had to be a single void *. They walked the >> > > control flow tree recursively, doing a depth-first search, and called >> > > the callback in a preorder, matching the order of the original source >> > > code. But since each node in the control flow tree has a pointer to >> > > its >> > > parent, we can implement a "get-next" and "get-previous" method that >> > > does the same thing that the recursive function did with no state at >> > > all. This lets us rewrite nir_foreach_block() as a simple for loop, >> > > which lets us greatly simplify its users in some cases. This does >> > > require us to rewrite every user, although the transformation from the >> > > old nir_foreach_block() to the new nir_foreach_block() is mostly >> > > trivial. >> > > >> > > One subtlety, though, is that the new nir_foreach_block() won't handle >> > > the case where the current block is deleted, which the old one could. >> > > There's a new nir_foreach_block_safe() which implements the standard >> > > trick for solving this. Most users don't modify control flow, though, >> > > so >> > > they won't need it. Right now, only opt_select_peephole needs it. >> > > >> > > Signed-off-by: Connor Abbott <<a href="mailto:cwabbott0@gmail.com">cwabbott0@gmail.com</a>> >> > > --- >> > > src/compiler/nir/nir.c | 186 >> > > +++++++++++++++++++++++++++++-------------------- >> > > src/compiler/nir/nir.h | 57 ++++++++++++--- >> > > 2 files changed, 159 insertions(+), 84 deletions(-) >> > > >> > > diff --git a/src/compiler/nir/nir.c b/src/compiler/nir/nir.c >> > > index b67916d..ea8aa88 100644 >> > > --- a/src/compiler/nir/nir.c >> > > +++ b/src/compiler/nir/nir.c >> > > @@ -1468,109 +1468,143 @@ nir_ssa_def_rewrite_uses_after(nir_ssa_def >> > > *def, nir_src new_src, >> > > nir_if_rewrite_condition(use_src->parent_if, new_src); >> > > } >> > > >> > > -static bool foreach_cf_node(nir_cf_node *node, nir_foreach_block_cb >> > > cb, >> > > - bool reverse, void *state); >> > > - >> > > -static inline bool >> > > -foreach_if(nir_if *if_stmt, nir_foreach_block_cb cb, bool reverse, >> > > void *state) >> > > +nir_block * >> > > +nir_block_cf_tree_next(nir_block *block) >> > > { >> > > - if (reverse) { >> > > - foreach_list_typed_reverse_safe(nir_cf_node, node, node, >> > > - &if_stmt->else_list) { >> > > - if (!foreach_cf_node(node, cb, reverse, state)) >> > > - return false; >> > > - } >> > > + if (block == NULL) { >> > > + /* nir_foreach_block_safe() will call this function on a NULL >> > > block >> > > + * after the last iteration, but it won't use the result so >> > > just return >> > > + * NULL here. >> > > + */ >> > > + return NULL; >> > > + } >> > > >> > > - foreach_list_typed_reverse_safe(nir_cf_node, node, node, >> > > - &if_stmt->then_list) { >> > > - if (!foreach_cf_node(node, cb, reverse, state)) >> > > - return false; >> > > - } >> > > - } else { >> > > - foreach_list_typed_safe(nir_cf_node, node, node, >> > > &if_stmt->then_list) { >> > > - if (!foreach_cf_node(node, cb, reverse, state)) >> > > - return false; >> > > - } >> > > + nir_cf_node *cf_next = nir_cf_node_next(&block->cf_node); >> > > + if (cf_next) >> > > + return nir_cf_node_cf_tree_first(cf_next); >> > > >> > > - foreach_list_typed_safe(nir_cf_node, node, node, >> > > &if_stmt->else_list) { >> > > - if (!foreach_cf_node(node, cb, reverse, state)) >> > > - return false; >> > > - } >> > > + nir_cf_node *parent = block->cf_node.parent; >> > > + >> > > + switch (parent->type) { >> > > + case nir_cf_node_if: { >> > > + /* Are we at the end of the if? Go to the beginning of the else >> > > */ >> > > + nir_if *if_stmt = nir_cf_node_as_if(parent); >> > > + if (&block->cf_node == nir_if_last_then_node(if_stmt)) >> > > + return >> > > nir_cf_node_as_block(nir_if_first_else_node(if_stmt)); >> > > + /* We must be at the end of the else, fallthrough */ >> > > } >> > > >> > > - return true; >> > > + case nir_cf_node_loop: { >> > > + nir_cf_node *node = nir_cf_node_next(parent); >> > > + return nir_cf_node_as_block(node); >> > > + } >> > > + >> > > + case nir_cf_node_function: >> > > + return NULL; >> > > + >> > > + default: >> > > + unreachable("unknown cf node type"); >> > > + } >> > > } >> > > >> > > -static inline bool >> > > -foreach_loop(nir_loop *loop, nir_foreach_block_cb cb, bool reverse, >> > > void *state) >> > > +nir_block * >> > > +nir_block_cf_tree_prev(nir_block *block) >> > > { >> > > - if (reverse) { >> > > - foreach_list_typed_reverse_safe(nir_cf_node, node, node, >> > > &loop->body) { >> > > - if (!foreach_cf_node(node, cb, reverse, state)) >> > > - return false; >> > > - } >> > > - } else { >> > > - foreach_list_typed_safe(nir_cf_node, node, node, &loop->body) { >> > > - if (!foreach_cf_node(node, cb, reverse, state)) >> > > - return false; >> > > - } >> > > + if (block == NULL) { >> > > + /* do this for consistency with nir_block_cf_tree_next() */ >> > > + return NULL; >> > > } >> > > >> > > - return true; >> > > + nir_cf_node *cf_prev = nir_cf_node_prev(&block->cf_node); >> > > + if (cf_prev) >> > > + return nir_cf_node_cf_tree_last(cf_prev); >> > > + >> > > + nir_cf_node *parent = block->cf_node.parent; >> > > + >> > > + switch (parent->type) { >> > > + case nir_cf_node_if: { >> > > + /* Are we at the beginning of the else? Go to the end of the if >> > > */ >> > > + nir_if *if_stmt = nir_cf_node_as_if(parent); >> > > + if (&block->cf_node == nir_if_first_else_node(if_stmt)) >> > > + return nir_cf_node_as_block(nir_if_last_then_node(if_stmt)); >> > > + /* We must be at the beginning of the if, fallthrough */ >> > > + } >> > > + >> > > + case nir_cf_node_loop: { >> > > + nir_cf_node *node = nir_cf_node_prev(parent); >> > > + return nir_cf_node_as_block(node); >> > > + } >> > > + >> > > + case nir_cf_node_function: >> > > + return NULL; >> > > + >> > > + default: >> > > + unreachable("unknown cf node type"); >> > > + } >> > > } >> > > >> > > -static bool >> > > -foreach_cf_node(nir_cf_node *node, nir_foreach_block_cb cb, >> > > - bool reverse, void *state) >> > > +nir_block *nir_cf_node_cf_tree_first(nir_cf_node *node) >> > > { >> > > switch (node->type) { >> > > - case nir_cf_node_block: >> > > - return cb(nir_cf_node_as_block(node), state); >> > > - case nir_cf_node_if: >> > > - return foreach_if(nir_cf_node_as_if(node), cb, reverse, state); >> > > - case nir_cf_node_loop: >> > > - return foreach_loop(nir_cf_node_as_loop(node), cb, reverse, >> > > state); >> > > - break; >> > > + case nir_cf_node_function: { >> > > + nir_function_impl *impl = nir_cf_node_as_function(node); >> > > + return nir_start_block(impl); >> > > + } >> > > >> > > - default: >> > > - unreachable("Invalid CFG node type"); >> > > - break; >> > > + case nir_cf_node_if: { >> > > + nir_if *if_stmt = nir_cf_node_as_if(node); >> > > + return nir_cf_node_as_block(nir_if_first_then_node(if_stmt)); >> > > } >> > > >> > > - return false; >> > > -} >> > > + case nir_cf_node_loop: { >> > > + nir_loop *loop = nir_cf_node_as_loop(node); >> > > + return nir_cf_node_as_block(nir_loop_first_cf_node(loop)); >> > > + } >> > > + >> > > + case nir_cf_node_block: { >> > > + return nir_cf_node_as_block(node); >> > > + } >> > > >> > > -bool >> > > -nir_foreach_block_in_cf_node(nir_cf_node *node, nir_foreach_block_cb >> > > cb, >> > > - void *state) >> > > -{ >> > > - return foreach_cf_node(node, cb, false, state); >> > > + default: >> > > + unreachable("unknown node type"); >> > > + } >> > > } >> > > >> > > -bool >> > > -nir_foreach_block(nir_function_impl *impl, nir_foreach_block_cb cb, >> > > void *state) >> > > +nir_block *nir_cf_node_cf_tree_last(nir_cf_node *node) >> > > { >> > > - foreach_list_typed_safe(nir_cf_node, node, node, &impl->body) { >> > > - if (!foreach_cf_node(node, cb, false, state)) >> > > - return false; >> > > + switch (node->type) { >> > > + case nir_cf_node_function: { >> > > + nir_function_impl *impl = nir_cf_node_as_function(node); >> > > + return nir_impl_last_block(impl); >> > > } >> > > >> > > - return cb(impl->end_block, state); >> > > -} >> > > + case nir_cf_node_if: { >> > > + nir_if *if_stmt = nir_cf_node_as_if(node); >> > > + return nir_cf_node_as_block(nir_if_last_else_node(if_stmt)); >> > > + } >> > > >> > > -bool >> > > -nir_foreach_block_reverse(nir_function_impl *impl, >> > > nir_foreach_block_cb cb, >> > > - void *state) >> > > -{ >> > > - if (!cb(impl->end_block, state)) >> > > - return false; >> > > + case nir_cf_node_loop: { >> > > + nir_loop *loop = nir_cf_node_as_loop(node); >> > > + return nir_cf_node_as_block(nir_loop_first_cf_node(loop)); >> > > + } >> > > + >> > > + case nir_cf_node_block: { >> > > + return nir_cf_node_as_block(node); >> > > + } >> > > >> > > - foreach_list_typed_reverse_safe(nir_cf_node, node, node, >> > > &impl->body) { >> > > - if (!foreach_cf_node(node, cb, true, state)) >> > > - return false; >> > > + default: >> > > + unreachable("unknown node type"); >> > > } >> > > +} >> > > >> > > - return true; >> > > +nir_block *nir_cf_node_cf_tree_next(nir_cf_node *node) >> > > +{ >> > > + if (node->type == nir_cf_node_block) >> > > + return nir_cf_node_cf_tree_first(nir_cf_node_next(node)); >> > > + else if (node->type == nir_cf_node_function) >> > > + return NULL; >> > > + else >> > > + return nir_cf_node_as_block(nir_cf_node_next(node)); >> > > } >> > > >> > > nir_if * >> > > diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h >> > > index c19ae59..54cbcba 100644 >> > > --- a/src/compiler/nir/nir.h >> > > +++ b/src/compiler/nir/nir.h >> > > @@ -1513,6 +1513,12 @@ nir_start_block(nir_function_impl *impl) >> > > return (nir_block *) exec_list_get_head(&impl->body); >> > > } >> > > >> > > +static inline nir_block * >> > > +nir_impl_last_block(nir_function_impl *impl) >> > > +{ >> > > + return (nir_block *) exec_list_get_tail(&impl->body); >> > > +} >> > > + >> > > static inline nir_cf_node * >> > > nir_cf_node_next(nir_cf_node *node) >> > > { >> > > @@ -2077,14 +2083,49 @@ void nir_ssa_def_rewrite_uses(nir_ssa_def >> > > *def, nir_src new_src); >> > > void nir_ssa_def_rewrite_uses_after(nir_ssa_def *def, nir_src >> > > new_src, >> > > nir_instr *after_me); >> > > >> > > -/* visits basic blocks in source-code order */ >> > > -typedef bool (*nir_foreach_block_cb)(nir_block *block, void *state); >> > > -bool nir_foreach_block(nir_function_impl *impl, nir_foreach_block_cb >> > > cb, >> > > - void *state); >> > > -bool nir_foreach_block_reverse(nir_function_impl *impl, >> > > nir_foreach_block_cb cb, >> > > - void *state); >> > > -bool nir_foreach_block_in_cf_node(nir_cf_node *node, >> > > nir_foreach_block_cb cb, >> > > - void *state); >> > >> > >> > so, I like the new iterator macros, but this is one giant massive >> > unbisectable flag-day change :-( >> > >> > I'd prefer an approach that kept the old fxns implemented in terms of >> > the new macros at the beginning of the patchset, then removed them >> > once everyone else was converted. Which is slightly annoying since >> > you'd kinda want to use the same names. But less of a pita wrt new >> > nir passes that haven't been pushed yet (I've got a bunch.. I'm not >> > sure if all of Jason's vulkan stuff has landed yet either) >> >> I think enough Vulkan stuff has landed to make this not terrible but >> you're right about the scope of things. How about starting with a patch >> that renames nir_foreach_block to something else, say >> nir_foreach_block_call. Then patch 1 then a patch to implement >> nir_foreach_block_call in terms of the macro and then the switchover >> patches. The rename will have to touch everything but it will be trivially >> correct. The rest can be incremental. >> >> That said, I'm still going to look through the patches to see what I think >> of the end result. >> >> > BR, >> > -R >> > >> > > +/* >> > > + * finds the next basic block in source-code order, returns NULL if >> > > there is >> > > + * none >> > > + */ >> > > + >> > > +nir_block *nir_block_cf_tree_next(nir_block *block); >> > > + >> > > +/* Performs the opposite of nir_block_cf_tree_next() */ >> > > + >> > > +nir_block *nir_block_cf_tree_prev(nir_block *block); >> > > + >> > > +/* Gets the first block in a CF node in source-code order */ >> > > + >> > > +nir_block *nir_cf_node_cf_tree_first(nir_cf_node *node); >> > > + >> > > +/* Gets the last block in a CF node in source-code order */ >> > > + >> > > +nir_block *nir_cf_node_cf_tree_last(nir_cf_node *node); >> > > + >> > > +/* Gets the next block after a CF node in source-code order */ >> > > + >> > > +nir_block *nir_cf_node_cf_tree_next(nir_cf_node *node); >> > > + >> > > +/* Macros for loops that visit blocks in source-code order */ >> > > + >> > > +#define nir_foreach_block(impl, block) \ >> > > + for (nir_block *block = nir_start_block(impl); block != NULL; \ >> > > + block = nir_block_cf_tree_next(block)) > > > I'm sorry in advance for this comment, but can we put impl and block in the > other order. This is something that's been bothering me for some time now. > NIR's iterators are inconsistent as to which order the parameters go. This > isn't your fault at all; I'm the one who added most of them. :-( In most > languages that have a foreach such as C++11, Java, and python, it's usually > "for (thing : container)" or "for thing in container:". I think we should > follow that convention. > > I'll write the patches to fix the others, but let's do this one correctly. </div></div>Well, from looking through nir.h it seems like most of the iterators use the same order I did. The only ones that don't are nir_foreach_variable() and nir_foreach_variable_safe().</blockquote><div> </div><div>Yes, I know and I personally find that order more natural. But I think consistency with other languages is important too. </div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> I'd rather keep them consistent with each other now, and then change everything at once. As-is, it would stick out like a sore thumb, especially since after this series it's a relatively common pattern to do: nir_foreach_block(impl, block) { nir_foreach_instr(block, instr) { ... } } After all, changing the other iterators would have to be a flag-day rename touching basically everything already, so it can't be much worse if you change nir_foreach_block() as well. <div class="HOEnZb"><div class="h5"></div></div></blockquote><div> </div><div>I guess. However, I don't see why we need to add something now and change the order later. Other than who has to go make the changes. :-P </div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="HOEnZb"><div class="h5"> > >> > > + >> > > +#define nir_foreach_block_safe(impl, block) \ >> > > + for (nir_block *block = nir_start_block(impl), \ >> > > + *next = nir_block_cf_tree_next(block); \ >> > > + block != NULL; \ >> > > + block = next, next = nir_block_cf_tree_next(block)) >> > > + >> > > +#define nir_foreach_block_reverse(impl, block) \ >> > > + for (nir_block *block = nir_impl_last_block(impl); block != NULL; >> > > \ >> > > + block = nir_block_cf_tree_prev(block)) >> > > + >> > > +#define nir_foreach_block_in_cf_node(node, block) \ >> > > + for (nir_block *block = nir_cf_node_cf_tree_first(node); \ >> > > + block != nir_cf_node_cf_tree_next(node); \ >> > > + block = nir_block_cf_tree_next(block)) >> > > >> > > /* If the following CF node is an if, this function returns that if. >> > > * Otherwise, it returns NULL. >> > > -- >> > > 2.5.0 >> > > >> > > _______________________________________________ >> > > mesa-dev mailing list >> > > <a href="mailto:mesa-dev@lists.freedesktop.org">mesa-dev@lists.freedesktop.org</a> >> > > <a href="https://lists.freedesktop.org/mailman/listinfo/mesa-dev" rel="noreferrer" target="_blank">https://lists.freedesktop.org/mailman/listinfo/mesa-dev</a> >> > _______________________________________________ >> > mesa-dev mailing list >> > <a href="mailto:mesa-dev@lists.freedesktop.org">mesa-dev@lists.freedesktop.org</a> >> > <a href="https://lists.freedesktop.org/mailman/listinfo/mesa-dev" rel="noreferrer" target="_blank">https://lists.freedesktop.org/mailman/listinfo/mesa-dev</a> > > </div></div></blockquote></div> </div></div>