* Clarify Cranelift's design with respect to mid-level optimization.
Cranelift doesn't currently do much mid-level optimization, however it
is something we're thinking about, so remove text describing it as out of
scope, and add more text explaining the vision for how it would fit into
the overall system.
* Implement wasm trap handlers.
This adds signal handlers based on SpiderMonkey's signal-handler code.
The functionality for looking up the trap code and wasm bytecode offset
isn't yet implemented, but this is a start.
I considered rewriting this code in Rust, but decided against it for now
as C++ allows us to talk to the relevant OS APIs more directly.
Fixes#15.
* Compile with -std=c++11.
* Refactor InstallState initialization.
* Compile with -fPIC.
* Factor out the code for calling a wasm function with a given index.
* Fix unclear wording in a comment.
* Fix verifier printing to print instruction encodings consistently.
Use `FuncWriter::write_instruction` for all instructions so that
encodings are printed consistently.
* Make use-before-def errors mention the relevant value.
* When there are verifier errors, print a message at the end.
* Make verifier errors prettier.
Fix the length of the "^~~~~" to match the printed entity, and print the
error messsage on its own line.
* Clean up "test verifier" failure messages.
* Tidy the uses-value-from-itself error.
The use instruction is the same as the def instruction, so don't print
both. Also, the use instruction is already being printed at the
beginning, so don't print it again at the end.
* Impoved support for wasm global imports
* Refactored parse_import_section improving readability
* Improved support for wasm table imports
* Improved support for wasm memory imports
* Improved formatting
* Added DefinedGlobalIndex, DefinedMemoryIndex, DefinedTableIndex structs
Memory access instructions which took the GPR_ZERO_DEREF_SAFE register
class (that was removed in #600) should check for the need of either an
offset (r13/rbp) or the SIB byte (r12/rsp). Some load/store instructions
would already take an index, thus already contain the SIB byte in this
case (see instructions which have a comment telling that the else branch
already contains an SIB byte). Non-indexed memory accesses lacked the
SIB byte check, which this patch adds.
This is a followup to af2a952aabd82cf401cc664d0262b139ff92d86b. It
teaches the spilling pass to use the is_ghost() property to test whether
to visit instructions. This fixes a bug handling multiple return values
with fallthrough_return.
