Rllvm (version 0.7-0)

.llvm: Invoke an LLVM Function from R

Description

These functions provide the mechanism to call an LLVM Function, passing it R objects as arguments. This is analogous to the .C interface, but for routines generated via LLVM, either read from existing files or generated in the R session.

Usage

.llvm(.x, ..., .args = list(...),
      .ee = ExecutionEngine(as(.x, "Module")),
      .all = FALSE, .duplicate = .duplicateArgs(.x),
      .ffi = TRUE)

Arguments

.x

the reference to the LLVM Function object

…

arguments for the Function

.args

an alternative way mechanism to pass the arguments for the Function as a single R list.

.ee

the LLVM ExecutionEngine providing the context for the Function. This can be created for each call or an instance can be reused across calls.

.all

a logical value that controls whether all of the arguments are also returned, or just the return value from the Function is returned. When the Function can modify any of the arguments .all = TRUE is typically important.

.duplicate

a logical vector indicating which arguments need to be copied before being passed to the Function. This allows us to avoid copying inputs which are not mutated/modified by the Function.

.ffi

a logical value or a CIF object. If this is TRUE, we use the Rffi package and the .llvmFFI in this package to invoke the routine. If .ffi is FALSE, we use the ExecutionEngine's runFunction routine. For the MCJIT engine, this is currently (LLVM 3.8) very limited and only allows us to call routines from a small number of possible signatures. Therefore, we use .ffi = TRUE by default. This currently does not comprehensively coerce arguments to the appropriate type. However, this may change soon. Also, we will support more types in the future. For now, however, it covers the common types, and is much more flexible than MCJIT::runFunction(). (MCJIT::runFunction() basically only supports the common signatures for main()/exec() routines, i.e. void|int fun(int , char *[]) and int fun(int), or routines with no parameters.

Value

If .all is FALSE, the return value from Function is returned as an R object.

References

http://llvm.org

See Also

The RLLVMCompile package parseIR Module, Function

Examples

# NOT RUN {
  module = parseIR(system.file("IR", "fib.ll", package = "Rllvm"))
  .llvm(module$fib, 11)
# }