MLton 20180207

http://mlton.org/Release20180207

• Compiler.
  • Added an experimental LLVM codegen (-codegen llvm); requires LLVM tools (llvm-as, opt, llc) version ≥ 3.7.
  • Made many substantial cosmetic improvements to front-end diagnostic messages, especially with respect to source location regions, type inference for fun and val rec declarations, signature constraints applied to a structure, sharing type specifications and where type signature expressions, type constructor or type variable escaping scope, and nonexhaustive pattern matching.
  • Fixed minor bugs with exception replication, precedence parsing of function clauses, and simultaneous sharing of multiple structures.
  • Made compilation deterministic (eliminate output executable name from compile-time specified @MLton runtime arguments; deterministically generate magic constant for executable).
  • Updated -show-basis (recursively expand structures in environments, displaying components with long identifiers; append (* @ region *) annotations to items shown in environment).
  • Forced amd64 codegen to generate PIC on amd64-linux targets.
• Runtime.
  • Added gc-summary-file file runtime option.
  • Reorganized runtime support for IntInf operations so that programs that do not use IntInf compile to executables with no residual dependency on GMP.
  • Changed heap representation to store forwarding pointer for an object in the object header (rather than in the object data and setting the header to a sentinel value).
• Language.
  • Added support for selected SuccessorML features; see http://mlton.org/SuccessorML for details.
  • Added (*#showBasis "file" *) directive; see http://mlton.org/ShowBasisDirective for details.
  • FFI:
    • Added pure, impure, and reentrant attributes to _import. An unattributed _import is treated as impure. A pure _import may be subject to more aggressive optimizations (common subexpression elimination, dead-code elimination). An _import-ed C function that (directly or indirectly) calls an _export-ed SML function should be attributed reentrant.
  • ML Basis annotations.
    • Added allowSuccessorML {false|true} to enable all SuccessorML features and other annotations to enable specific SuccessorML features; see http://mlton.org/SuccessorML for details.
    • Split nonexhaustiveMatch {warn|error|igore} and redundantMatch {warn|error|ignore} into nonexhaustiveMatch and redundantMatch (controls diagnostics for case expressions, fn expressions, and fun declarations (which may raise Match on failure)) and nonexhaustiveBind and redundantBind (controls diagnostics for val declarations (which may raise Bind on failure)).
    • Added valrecConstr {warn|error|ignore} to report when a val rec (or fun) declaration redefines an identifier that previously had constructor status.
• Libraries.
  • Basis Library.
    • Improved performance of Array.copy, Array.copyVec, Vector.append, String.^, String.concat, String.concatWith, and other related functions by using memmove rather than element-by-element constructions.
  • Unsafe structure.
    • Added unsafe operations for array uninitialization and raw arrays; see #207 for details.
  • Other libraries.
    • Updated: ckit library, MLLPT library, MLRISC library, SML/NJ library
• Tools.
  • mlnlffigen
    • Updated to warn and skip (rather than abort) when encountering functions with struct/union argument or return type.

For a complete list of changes and bug fixes since Release20130715, see the CHANGELOG and Bugs20130715.