A warm build that finds the program's LLVM in the cache read the file into
one string before emitting the program object. A program whose LLVM is
past the engine's string limit (three.js nodes, 816 MB) failed there with
`RangeError: Invalid string length`, though its cold build, which keeps
the LLVM in parts, succeeds. The cache hit now reads the file with
readTextParts: parts of at most 64 Mi UTF-16 units, decoded across reads,
none ending inside a surrogate pair, which the emitter takes as a cold
build hands them over.
Chris Tate
927504af87