version_65: Handle EM_ASM/EM_JS in LLVM wasm backend O0 output (#1888)

See emscripten-core/emscripten#7928 - we have been optimizing all wasms until now, and noticed this when the wasm object file path did not do so. When not optimizing, our methods of handling EM_ASM and EM_JS fail since the patterns are different.

Specifically, for EM_ASM we hunt for emscripten_asm_const(X, where X is a constant, but without opts it may be a get of a local. For EM_JS, the function body may not just contain a const, but a block with a set of the const and a return of a get later.

This adds logic to track gets and sets in basic blocks, which is sufficient to handle this.

1.38.25: More misc ASAN fixes (#1882)

* fix buffer overflow in simple_ast.h printing.
* check wasm binary format reading of function export indexes for errors.
* check if s-expr format imports have a non-empty module and base.

Fixes #1876
Fixes #1877
Fixes #1879

1.38.24: Emscripten stack simplification (#1870)

This takes advantage of the recent memory simplification in emscripten, where JS static allocation is done at compile time. That means we know the stack's initial location at compile time, and can apply it. This is the binaryen side of that:

* asm2wasm support for asm.js globals with an initial value var X = Y; where Y is not 0 (which is what the stack now is).
* wasm-emscripten-finalize support for a flag --initial-stack-pointer=X, and remove the old code to import the stack's initial location.

version_64: Emscripten stack simplification (#1870)

This takes advantage of the recent memory simplification in emscripten, where JS static allocation is done at compile time. That means we know the stack's initial location at compile time, and can apply it. This is the binaryen side of that:

* asm2wasm support for asm.js globals with an initial value var X = Y; where Y is not 0 (which is what the stack now is).
* wasm-emscripten-finalize support for a flag --initial-stack-pointer=X, and remove the old code to import the stack's initial location.

1.38.23: Code style improvements (#1868)

* Use modern T p = v; notation to initialize class fields
* Use modern X() = default; notation for empty class constructors

version_63

Don't emit simd in fuzzer unless requested (some code paths we missed…

version_62: Fix fuzzing JS glue code (#1843)

After we added logging to the fuzzer, we forgot to add to the JS glue code the necessary imports so it can be run there too.

Also adds legalization for the JS glue code imports and exports.

Also adds a missing validator check on imports having a function type (the fuzzing code was missing one).

Fixes #1842

version_61: wasm-emscripten-finalize: Add tableSize to metadata (#1826)

This allows emscripten to generate table of the correct size.
Right now is simply defaults to creating a table to size 1024.

version_60: No exit runtime pass (#1816)

When emscripten knows that the runtime will not be exited, it can tell codegen to not emit atexit() calls (since those callbacks will never be run). This saves both code size and startup time. In asm2wasm the JSBackend does it directly. For the wasm backend, this pass does the same on the output wasm.

version_59

wasm-emscripten-finalize: import env.STACKTOP, like asm2wasm does