layout: Rewrite the block formatting context/float inline-size

speculation code.

The old code tried to do the speculation as a single bottom-up pass
after intrinsic inline-size calculation, which was unable to handle
cases like this:

    <div>
        <div style="float: left">Foo</div>
    </div>
    <div>
        <div style="overflow: hidden">Bar</div>
    </div>

No single bottom-up pass could possibly handle this case, because the
inline-size of the float flowing out of the "Foo" block could never make
it down to the "Bar" block, where it is needed for speculation.

On the pages I tried, this regresses layout performance by 1%-2%.

I first noticed this breaking some pages, like the Google SERPs, several
months ago.
This commit is contained in:
Patrick Walton 2016-03-18 15:23:08 -07:00
parent 9b2ae3a62f
commit b29719e36b
15 changed files with 346 additions and 184 deletions

View file

@ -12,8 +12,8 @@ use block::{ISizeConstraintInput, ISizeConstraintSolution};
use context::LayoutContext;
use display_list_builder::{BlockFlowDisplayListBuilding, BorderPaintingMode, DisplayListBuildState};
use euclid::Point2D;
use flow::{BaseFlow, IMPACTED_BY_RIGHT_FLOATS, ImmutableFlowUtils, OpaqueFlow};
use flow::{self, EarlyAbsolutePositionInfo, Flow, FlowClass, IMPACTED_BY_LEFT_FLOATS};
use flow::{BaseFlow, EarlyAbsolutePositionInfo, Flow, FlowClass, ImmutableFlowUtils, OpaqueFlow};
use flow::{self};
use flow_list::MutFlowListIterator;
use fragment::{Fragment, FragmentBorderBoxIterator, Overflow};
use gfx::display_list::{StackingContext, StackingContextId};
@ -392,10 +392,6 @@ impl Flow for TableFlow {
}
}
// As tables are always wrapped inside a table wrapper, they are never impacted by floats.
self.block_flow.base.flags.remove(IMPACTED_BY_LEFT_FLOATS);
self.block_flow.base.flags.remove(IMPACTED_BY_RIGHT_FLOATS);
let column_computed_inline_sizes = &self.column_computed_inline_sizes;
let collapsed_inline_direction_border_widths_for_table =
&self.collapsed_inline_direction_border_widths_for_table;