Maintain an explicit "reachable" flag when decoding wasm. Push placeholder
frames on the control-flow stack instead of just maintaining a count of
the stack depth in unreachable code, so that we can whether If blocks
have Elses, and whether block exits are branched to, in all contexts.
Fixes#217.
With the change to the parser to preserve indices, it now inserts
placeholders to pad out index spaces as needed. Placeholder functions
use reserved signature indices, so skip them when writing them out,
to avoid writing them out as "sig4294967295".
Cretonne clients don't need to know how the register allocator works.
Export the RegDiversions type from the binemit module instead. It is
used by the "test binemit" driver.
StackSlotKind::OutgoingArg stack slots have an offset that is relative
to our own stack pointer, while all other stack slot kinds have offsets
that are relative to the caller's stack pointer.
Make sure we generate the right sp-relative offsets for outgoing
arguments too.
This makes it easier to debug testcases:
- the entity numbers in a .cton file match the entity numbers used
within Cretonne.
- serializing and deserializing doesn't cause indices to change.
One disadvantage is that if a .cton file uses sparse entity numbers,
deserializing to the in-memory form doesn't compact it. However, the
text format is not intended to be performance-critical, so this isn't
expected to be a big burden.
When the input is a NaN, we need to generate a different trap code, so
use the new trapff instruction to generate such a trap after the first
floating point comparison.
This is the floating point equivalent of trapif: Trap when a given
condition is in the floating-point flags.
Define Intel encodings comparable to the trapif encodings.
This enables code generation that never causes a SIGFPE signal to be
raised from a division instruction. Instead, division and remainder
calculations are protected by explicit traps.
* gen_settings: dont try to display a Preset descriptor in Flags
Trying to display a preset doesnt make sense, and before this commit it
does not display anything meaningful - the printout just says e.g.
"haswell =\n".
The offset byte a preset descriptor isnt a valid offset into the
flag bytes, it is actually an offset into the PRESETS table. It will
cause a panic when the offset is out of bounds for the flag bytes,
which happens in the intel isa as of this commit.
* intel settings: test that display impl doesnt panic
This instruction loads a stack limit from a global variable and compares
it to the stack pointer, trapping if the stack has grown beyond the
limit.
Also add a expand_flags transform group containing legalization patterns
for ISAs with CPU flags.
Fixes#234.
The instruction set has variants with 8-bit and 32-bit signed immediate
operands.
Add a TODO to use a TEST instruction for the special case ifcmp_imm x, 0.
