codegen: use compiler trampoline closing over method-instance (#26565)

Uses a trampoline to reduce the number of jump checks to happen during dynamic dispatch. It used to be done this way initially, but that got lost for awhile after the function-types PR. This brings back the ability to directly call a method without going through the dispatch helper function.

Replaces jlcall_api with inspection of the invoke closure to see if it is a known entity.

Author: vtjnash

base/compiler/optimize.jl

@@ -367,7 +367,7 @@ function optimize(me::InferenceState)
 
         if proven_pure && !coverage_enabled()
             # use constant calling convention
-            # Do not emit `jlcall_api == 2` if coverage is enabled
+            # Do not emit `jl_fptr_const_return` if coverage is enabled
             # so that we don't need to add coverage support
             # to the `jl_call_method_internal` fast path
             # Still set pure flag to make sure `inference` tests pass
@@ -438,7 +438,7 @@ function finish(me::InferenceState)
         end
 
         # don't store inferred code if we've decided to interpret this function
-        if !already_inferred && me.linfo.jlcall_api != 4
+        if !already_inferred && invoke_api(me.linfo) != 4
             const_flags = (me.const_ret) << 1 | me.const_api
             if me.const_ret
                 if isa(me.bestguess, Const)
@@ -1320,7 +1320,7 @@ function inlineable(@nospecialize(f), @nospecialize(ft), e::Expr, atypes::Vector
     isa(linfo, MethodInstance) || return invoke_NF(argexprs0, e.typ, atypes0, sv,
                                                    atype_unlimited, invoke_data)
     linfo = linfo::MethodInstance
-    if linfo.jlcall_api == 2
+    if invoke_api(linfo) == 2
         # in this case function can be inlined to a constant
         add_backedge!(linfo, sv)
         return inline_as_constant(linfo.inferred_const, argexprs, sv, invoke_data)

base/compiler/typeinfer.jl

@@ -164,7 +164,7 @@ function typeinf_code(linfo::MethodInstance, optimize::Bool, cached::Bool,
             # so need to check whether the code itself is also inferred
             if min_world(linfo) <= params.world <= max_world(linfo)
                 inf = linfo.inferred
-                if linfo.jlcall_api == 2
+                if invoke_api(linfo) == 2
                     method = linfo.def::Method
                     tree = ccall(:jl_new_code_info_uninit, Ref{CodeInfo}, ())
                     tree.code = Any[ Expr(:return, quoted(linfo.inferred_const)) ]

base/compiler/utilities.jl

@@ -88,6 +88,10 @@ end
 # MethodInstance/CodeInfo #
 ###########################
 
+function invoke_api(li::MethodInstance)
+    return ccall(:jl_invoke_api, Cint, (Any,), li)
+end
+
 function get_staged(li::MethodInstance)
     try
         # user code might throw errors – ignore them

src/ast.c

@@ -993,7 +993,7 @@ static jl_value_t *jl_invoke_julia_macro(jl_array_t *args, jl_module_t *inmodule
             // unreachable
         }
         *ctx = mfunc->def.method->module;
-        result = jl_call_method_internal(mfunc, margs, nargs);
+        result = mfunc->invoke(mfunc, margs, nargs);
     }
     JL_CATCH {
         if (jl_loaderror_type == NULL) {

src/builtins.c

@@ -1179,13 +1179,13 @@ static void add_builtin(const char *name, jl_value_t *v)
     jl_set_const(jl_core_module, jl_symbol(name), v);
 }
 
-jl_fptr_t jl_get_builtin_fptr(jl_value_t *b)
+jl_fptr_args_t jl_get_builtin_fptr(jl_value_t *b)
 {
     assert(jl_isa(b, (jl_value_t*)jl_builtin_type));
-    return jl_gf_mtable(b)->cache.leaf->func.linfo->fptr;
+    return jl_gf_mtable(b)->cache.leaf->func.linfo->specptr.fptr1;
 }
 
-static void add_builtin_func(const char *name, jl_fptr_t fptr)
+static void add_builtin_func(const char *name, jl_fptr_args_t fptr)
 {
     jl_mk_builtin_func(NULL, name, fptr);
 }