WIP: Simplify extraction of binary of dynamic size

Does not build for:

* jit/x86
* emu

erts/emulator/beam/erl_bits.c

@@ -511,7 +511,7 @@ Process *p, Uint num_bits, unsigned flags, ErlSubBits *sb)
 }
 
 Eterm
-erts_bs_get_binary_2(Process *p, Uint num_bits, unsigned flags, ErlSubBits *sb)
+erts_bs_get_binary_2(Process *p, Uint num_bits, ErlSubBits *sb)
 {
     Eterm result;
 

erts/emulator/beam/erl_bits.h

@@ -213,7 +213,7 @@ Eterm erts_bs_get_float_2(Process *p, Uint num_bits, unsigned flags, ErlSubBits*
 
 /* These will create heap binaries when appropriate, so they require free space
  * up to BUILD_SUB_BITSTRING_HEAP_NEED. */
-Eterm erts_bs_get_binary_2(Process *p, Uint num_bits, unsigned flags, ErlSubBits* sb);
+Eterm erts_bs_get_binary_2(Process *p, Uint num_bits, ErlSubBits* sb);
 Eterm erts_bs_get_binary_all_2(Process *p, ErlSubBits* sb);
 
 /* Binary construction, new instruction set. */

erts/emulator/beam/jit/arm/generators.tab

@@ -302,35 +302,6 @@ gen.new_small_map_lit(Dst, Live, Size, Rest) {
     return op;
 }
 
-// Generate the fastest instruction to fetch a binary from a binary.
-gen.get_binary2(Fail, Ms, Live, Size, Unit, Flags, Dst) {
-    BeamOp* op;
-
-    $NewBeamOp(S, op);
-    $NativeEndian(Flags);
-
-    if (Size.type == TAG_a && Size.val == am_all) {
-        $BeamOpNameArity(op, i_bs_get_binary_all2, 5);
-        op->a[0] = Ms;
-        op->a[1] = Fail;
-        op->a[2] = Live;
-        op->a[3] = Unit;
-        op->a[4] = Dst;
-    } else {
-        $BeamOpNameArity(op, i_bs_get_binary2, 6);
-        op->a[0] = Ms;
-        op->a[1] = Fail;
-        op->a[2] = Live;
-        op->a[3] = Size;
-        op->a[4].type = TAG_u;
-        op->a[4].val = (Unit.val << 3) | Flags.val;
-        op->a[5] = Dst;
-    }
-
-    op->next = NULL;
-    return op;
-}
-
 gen.skip_utf16(Fail, Ms, Flags) {
     BeamOp* op;
     $NewBeamOp(S, op);

erts/emulator/beam/jit/arm/instr_bs.cpp

@@ -551,13 +551,13 @@ void BeamModuleAssembler::emit_i_bs_get_binary2(const ArgRegister &Ctx,
                                                 const ArgLabel &Fail,
                                                 const ArgWord &Live,
                                                 const ArgSource &Size,
-                                                const ArgWord &Flags,
+                                                const ArgWord &Unit,
                                                 const ArgRegister &Dst) {
     Label fail;
     int unit;
 
     fail = resolve_beam_label(Fail, dispUnknown);
-    unit = Flags.get() >> 3;
+    unit = Unit.get();
 
     if (emit_bs_get_field_size(Size, unit, fail, ARG2) >= 0) {
         a.str(ARG2, TMP_MEM1q);
@@ -569,14 +569,13 @@ void BeamModuleAssembler::emit_i_bs_get_binary2(const ArgRegister &Ctx,
                               Ctx,
                               ARG4);
 
-        emit_untag_ptr(ARG4, ARG4);
+        emit_untag_ptr(ARG3, ARG4);
 
         emit_enter_runtime<Update::eHeapOnlyAlloc>(Live.get());
 
         a.mov(ARG1, c_p);
         a.ldr(ARG2, TMP_MEM1q);
-        mov_imm(ARG3, Flags.get());
-        runtime_call<4>(erts_bs_get_binary_2);
+        runtime_call<3>(erts_bs_get_binary_2);
 
         emit_leave_runtime<Update::eHeapOnlyAlloc>(Live.get());
 

erts/emulator/beam/jit/arm/ops.tab

@@ -974,8 +974,11 @@ i_bs_match_string S f W M
 bs_get_integer2 f S t s t t d
 
 # Fetching binaries from binaries.
-bs_get_binary2 Fail=f Ms=xy Live=u Sz=sq Unit=u Flags=u Dst=d =>
-    get_binary2(Fail, Ms, Live, Sz, Unit, Flags, Dst)
+bs_get_binary2 Fail=f Ms=xy Live=u _Sz=a==am_all Unit=u _Flags=u Dst=d =>
+    i_bs_get_binary_all2 Ms Fail Live Unit Dst
+
+bs_get_binary2 Fail=f Ms=xy Live=u Sz=s Unit=u _Flags=u Dst=d =>
+    i_bs_get_binary2 Ms Fail Live Sz Unit Dst
 
 i_bs_get_binary2 S f t s t d
 i_bs_get_binary_all2 S f t t d