This changes locals from being declared by the emitLocal hook in
WebAssemblyTargetStreamer, rather than with an instruction. After exploring
the infastructure in LLVM more, this seems to make more sense since
declaring locals doesn't use an encoded opcode.
This also adds more 0xd opcodes, type encodings, and miscellaneous
binary encoding bits.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285040 91177308-0d34-0410-b5e6-96231b3b80d8
WebAssembly has officially switched from being an AST to being a stack
machine. Update various bits of terminology and README.md entries
accordingly.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@283154 91177308-0d34-0410-b5e6-96231b3b80d8
Avoid implicit conversions from MachineInstrBundleIterator to
MachineInstr* in the WebAssembly backend by preferring MachineInstr&
over MachineInstr*.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@274912 91177308-0d34-0410-b5e6-96231b3b80d8
This implements a very simple conservative transformation that doesn't
require more than linear code size growth. There's room for much more
optimization in this space.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@262982 91177308-0d34-0410-b5e6-96231b3b80d8
WebAssembly doesn't require full RPO; topological sorting is sufficient and
can preserve more of the MachineBlockPlacement ordering. Unfortunately, this
still depends a lot on heuristics, because while we use the
MachineBlockPlacement ordering as a guide, we can't use it in places where
it isn't topologically ordered. This area will require further attention.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@260978 91177308-0d34-0410-b5e6-96231b3b80d8
Refine the test for whether an instruction is in an expression tree so that
it detects when one tree ends and another begins, so we can place a block
at that point, rather than continuing to find the first instruction not in
a tree at all.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@259294 91177308-0d34-0410-b5e6-96231b3b80d8
WebAssemblyCFGStackify does not track liveness for EXPR_STACK, causing
verifier failure if liveness has not already been invalidated.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@257620 91177308-0d34-0410-b5e6-96231b3b80d8
This patch changes the way labels are referenced. Instead of referencing the
basic-block label name (eg. .LBB0_0), instructions now just have an immediate
which indicates the depth in the control-flow stack to find a label to jump to.
This makes them much closer to what we expect to have in the binary encoding,
and avoids the problem of basic-block label names not being explicit in the
binary encoding.
Also, it terminates blocks and loops with end_block and end_loop instructions,
rather than basic-block label names, for similar reasons.
This will also fix problems where two constructs appear to have the same label,
because we no longer explicitly use labels, so consumers that need labels will
presumably create their own labels, and presumably they won't reuse labels
when they do.
This patch does make the code a little more awkward to read; as a partial
mitigation, this patch also introduces comments showing where the labels are,
and comments on each branch showing where it's branching to.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@257505 91177308-0d34-0410-b5e6-96231b3b80d8
Move RegStackify after coalescing and teach it to use LiveIntervals instead
of depending on SSA form. This avoids a problem where a register in a COPY
instruction is stackified and then subsequently coalesced with a register
that is not stackified.
This also puts it after the scheduler, which allows us to simplify the
EXPR_STACK constraint, as we no longer have instructions being reordered
after stackification and before coloring.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@256402 91177308-0d34-0410-b5e6-96231b3b80d8
WebAssembly is currently using labels to end scopes, so for example a
loop scope looks like this:
BB0_0:
loop BB0_1
...
BB0_1:
with BB0_0 being the label of the first block not in the loop. This
requires that the label be printed even when it's only reachable via
fallthrough. To arrange this, insert a no-op LOOP_END instruction in
such cases at the end of the loop.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253901 91177308-0d34-0410-b5e6-96231b3b80d8
Always starting blocks at the top of their containing loops works, but creates
unnecessarily deep nesting because it makes all blocks in a loop overlap.
Refine the BLOCK placement algorithm to start blocks at nearest common
dominating points instead, which significantly shrinks them and reduces
overlapping.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253876 91177308-0d34-0410-b5e6-96231b3b80d8
This pass implements a simple algorithm for conversion from CFG to
wasm's structured control flow. It doesn't yet handle multiple-entry
loops; that will be added in a future patch.
It also adds initial support for switch statements.
Differential Revision: http://reviews.llvm.org/D12735
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247818 91177308-0d34-0410-b5e6-96231b3b80d8
