Allow for nested targets

Author: vchuravy

src/driver.jl

@@ -222,7 +222,8 @@ const __llvm_initialized = Ref(false)
             for dyn_job in keys(worklist)
                 # cached compilation
                 dyn_entry_fn = get!(jobs, dyn_job) do
-                    config = CompilerConfig(dyn_job.config; toplevel=false)
+                    target = nest_target(dyn_job.config.target, job.config.target)
+                    config = CompilerConfig(dyn_job.config; toplevel=false, target)
                     dyn_ir, dyn_meta = codegen(:llvm, CompilerJob(dyn_job; config))
                     dyn_entry_fn = LLVM.name(dyn_meta.entry)
                     merge!(compiled, dyn_meta.compiled)

src/interface.jl

@@ -48,6 +48,9 @@ have_fma(@nospecialize(target::AbstractCompilerTarget), T::Type) = false
 
 dwarf_version(target::AbstractCompilerTarget) = Int32(4) # It seems every target supports v4 bar cuda
 
+# If your target performs nested compilation, this function should reconstruct your target with a new inner target
+nest_target(target::AbstractCompilerTarget, parent::AbstractCompilerTarget) = target
+
 ## params
 
 export AbstractCompilerParams