After we add any instruction to an EBB, we can't add EBB parameters
anymore. There is an assertion in `append_ebb_param` to detect this
error, but the backtrace generated doesn't give any hint what happened.
We add an error message to the assertion so the user can understand what
is wrong.
fixes#1003
Allocations associated with pushes to EbbHeaderBlockData::predecessors account
for 4.9% of all heap allocation (calls) in CL. This change avoids almost all
of them by changing it to be a SmallVec<[PredBlock; 4]>. Dynamic instruction
count falls by 0.15%.
* the target-lexicon crate no longer has or needs the std feature
in cargo, so we can delete all default-features=false, any mentions
of its std feature, and the nostd configs in many lib.rs files
* the representation of arm architectures has changed, so some case
statements needed refactoring
-Add resumable_trap, safepoint, isnull, and null instructions
-Add Stackmap struct and StackmapSink trait
Co-authored-by: Mir Ahmed <mirahmed753@gmail.com>
Co-authored-by: Dan Gohman <sunfish@mozilla.com>
