Merge pull request #2338 from pguyot/w25/jit_bitstring_extract_float-add-missing-nogc-alloc

JIT: add missing memory_ensure_free in jit_bitstring_extract_float

These changes are made under both the "Apache 2.0" and the "GNU Lesser General
Public License 2.1 or later" license terms (dual license).

SPDX-License-Identifier: Apache-2.0 OR LGPL-2.1-or-later

Author: bettio

libs/jit/src/jit.erl

@@ -1334,7 +1334,7 @@ first_pass(<<?OP_BS_GET_FLOAT2, Rest0/binary>>, MMod, MSt0, State0) ->
     ?ASSERT_ALL_NATIVE_FREE(MSt0),
     {Fail, Rest1} = decode_label(Rest0),
     {MSt1, Src, Rest2} = decode_typed_compact_term(Rest1, MMod, MSt0, State0),
-    {_Live, Rest3} = decode_literal(Rest2),
+    {Live, Rest3} = decode_literal(Rest2),
     {MSt2, Size, Rest4} = decode_typed_compact_term(Rest3, MMod, MSt1, State0),
     {Unit, Rest5} = decode_literal(Rest4),
     {FlagsValue, Rest6} = decode_literal(Rest5),
@@ -1348,24 +1348,19 @@ first_pass(<<?OP_BS_GET_FLOAT2, Rest0/binary>>, MMod, MSt0, State0) ->
                 MSt5 = MMod:mul(MSt4, SizeReg, Unit),
                 {MSt5, SizeReg}
         end,
-    {MSt7, BSBinaryReg} = MMod:get_array_element(MSt6, MatchStateRegPtr, 1),
-    {MSt8, BSOffsetReg} = MMod:get_array_element(MSt7, MatchStateRegPtr, 2),
-    {MSt9, Result} = MMod:call_primitive(MSt8, ?PRIM_BITSTRING_EXTRACT_FLOAT, [
-        ctx, {free, BSBinaryReg}, BSOffsetReg, NumBits, {free, FlagsValue}
+    {MSt7, Result} = MMod:call_primitive(MSt6, ?PRIM_BITSTRING_EXTRACT_FLOAT, [
+        ctx, jit_state, {free, MatchStateRegPtr}, {free, NumBits}, {free, FlagsValue}, Live
     ]),
-    MSt10 = cond_jump_to_label({Result, '==', ?FALSE_ATOM}, Fail, MMod, MSt9),
-    MSt11 = MMod:add(MSt10, BSOffsetReg, NumBits),
-    MSt12 = MMod:free_native_registers(MSt11, [NumBits]),
-    MSt13 = MMod:move_to_array_element(MSt12, BSOffsetReg, MatchStateRegPtr, 2),
-    MSt14 = MMod:free_native_registers(MSt13, [BSOffsetReg, MatchStateRegPtr]),
-    {MSt15, Dest, Rest7} = decode_dest(Rest6, MMod, MSt14),
+    MSt8 = handle_error_if({Result, '==', 0}, MMod, MSt7),
+    MSt9 = cond_jump_to_label({Result, '==', ?FALSE_ATOM}, Fail, MMod, MSt8),
+    {MSt10, Dest, Rest7} = decode_dest(Rest6, MMod, MSt9),
     ?TRACE("OP_BS_GET_FLOAT2 ~p,~p,~p,~p,~p,~p,~p\n", [
-        Fail, Src, _Live, Size, Unit, FlagsValue, Dest
+        Fail, Src, Live, Size, Unit, FlagsValue, Dest
     ]),
-    MSt16 = MMod:move_to_vm_register(MSt15, Result, Dest),
-    MSt17 = MMod:free_native_registers(MSt16, [Result]),
-    ?ASSERT_ALL_NATIVE_FREE(MSt17),
-    first_pass(Rest7, MMod, MSt17, State0);
+    MSt11 = MMod:move_to_vm_register(MSt10, Result, Dest),
+    MSt12 = MMod:free_native_registers(MSt11, [Result]),
+    ?ASSERT_ALL_NATIVE_FREE(MSt12),
+    first_pass(Rest7, MMod, MSt12, State0);
 % 119
 first_pass(<<?OP_BS_GET_BINARY2, Rest0/binary>>, MMod, MSt0, State0) ->
     ?ASSERT_ALL_NATIVE_FREE(MSt0),

src/libAtomVM/jit.c

@@ -1522,27 +1522,34 @@ static term jit_bitstring_extract_integer(
     }
 }
 
-static term jit_bitstring_extract_float(Context *ctx, term *bin_ptr, size_t offset, int n, int bs_flags)
+static term jit_bitstring_extract_float(Context *ctx, JITState *jit_state, term *match_state_ptr, int n, int bs_flags, int live)
 {
-    TRACE("jit_bitstring_extract_float: bin_ptr=%p offset=%d n=%d bs_flags=%d\n", (void *) bin_ptr, (int) offset, n, bs_flags);
+    TRACE("jit_bitstring_extract_float: match_state_ptr=%p n=%d bs_flags=%d live=%d\n", (void *) match_state_ptr, n, bs_flags, live);
+    avm_int_t offset = (avm_int_t) match_state_ptr[2];
     avm_float_t value;
     bool status;
     switch (n) {
         case 16:
-            status = bitstring_extract_f16((term) (((uintptr_t) bin_ptr) | TERM_PRIMARY_BOXED), offset, n, bs_flags, &value);
+            status = bitstring_extract_f16(match_state_ptr[1], offset, n, bs_flags, &value);
             break;
         case 32:
-            status = bitstring_extract_f32((term) (((uintptr_t) bin_ptr) | TERM_PRIMARY_BOXED), offset, n, bs_flags, &value);
+            status = bitstring_extract_f32(match_state_ptr[1], offset, n, bs_flags, &value);
             break;
         case 64:
-            status = bitstring_extract_f64((term) (((uintptr_t) bin_ptr) | TERM_PRIMARY_BOXED), offset, n, bs_flags, &value);
+            status = bitstring_extract_f64(match_state_ptr[1], offset, n, bs_flags, &value);
             break;
         default:
             status = false;
     }
     if (UNLIKELY(!status)) {
         return FALSE_ATOM;
     }
+    match_state_ptr[2] = (term) (offset + n);
+    TRIM_LIVE_REGS(live);
+    if (UNLIKELY(memory_ensure_free_with_roots(ctx, FLOAT_SIZE, live, ctx->x, MEMORY_CAN_SHRINK) != MEMORY_GC_OK)) {
+        set_error(ctx, jit_state, 0, OUT_OF_MEMORY_ATOM);
+        return term_invalid_term();
+    }
     return term_from_float(value, &ctx->heap);
 }
 

src/libAtomVM/jit.h

@@ -234,7 +234,7 @@ struct ModuleNativeInterface
     void *(*malloc)(Context *ctx, JITState *jit_state, size_t sz);
     void (*free)(void *ptr);
     term (*put_map_assoc)(Context *ctx, JITState *jit_state, term src, size_t new_entries, size_t num_elements, term *kv);
-    term (*bitstring_extract_float)(Context *ctx, term *bin_ptr, size_t offset, int n, int bs_flags);
+    term (*bitstring_extract_float)(Context *ctx, JITState *jit_state, term *match_state_ptr, int n, int bs_flags, int live);
     int (*module_get_fun_arity)(Module *fun_module, uint32_t fun_index);
     bool (*bitstring_match_module_str)(Context *ctx, JITState *jit_state, term bin, size_t offset, int str_id, size_t len);
     term (*bitstring_get_utf8)(term src);

src/libAtomVM/opcodesswitch.h

@@ -4399,7 +4399,6 @@ HOT_FUNC int scheduler_entry_point(GlobalContext *glb)
                 term src;
                 DECODE_COMPACT_TERM(src, pc);
                 uint32_t live;
-                UNUSED(live);
                 DECODE_LITERAL(live, pc);
                 term size;
                 DECODE_COMPACT_TERM(size, pc);
@@ -4442,7 +4441,8 @@ HOT_FUNC int scheduler_entry_point(GlobalContext *glb)
                 } else {
                     term_set_match_state_offset(src, bs_offset + increment);
 
-                    if (UNLIKELY(memory_ensure_free_opt(ctx, FLOAT_SIZE, MEMORY_NO_GC) != MEMORY_GC_OK)) {
+                    TRIM_LIVE_REGS(live);
+                    if (UNLIKELY(memory_ensure_free_with_roots(ctx, FLOAT_SIZE, live, x_regs, MEMORY_CAN_SHRINK) != MEMORY_GC_OK)) {
                         RAISE_ERROR(OUT_OF_MEMORY_ATOM);
                     }
                     term t = term_from_float(value, &ctx->heap);

tests/erlang_tests/CMakeLists.txt

@@ -570,6 +570,7 @@ compile_erlang(bs_context_byte_size)
 compile_erlang(bs_get_binary_fixed_size)
 compile_erlang(bs_get_integer_fixed_size)
 compile_erlang(bs_get_float_dynamic_size)
+compile_erlang(bs_get_float_gc)
 compile_erlang(test_is_not_equal)
 compile_assembler(test_is_not_equal_asm)
 compile_erlang(test_make_fun2)
@@ -1139,6 +1140,7 @@ set(erlang_test_beams
     bs_get_binary_fixed_size.beam
     bs_get_integer_fixed_size.beam
     bs_get_float_dynamic_size.beam
+    bs_get_float_gc.beam
     test_is_not_equal.beam
     test_is_not_equal_asm.beam
     test_make_fun2.beam

tests/erlang_tests/bs_get_float_gc.erl

@@ -0,0 +1,57 @@
+%
+% This file is part of AtomVM.
+%
+% Copyright 2026 Paul Guyot <pguyot@kallisys.net>
+%
+% Licensed under the Apache License, Version 2.0 (the "License");
+% you may not use this file except in compliance with the License.
+% You may obtain a copy of the License at
+%
+%    http://www.apache.org/licenses/LICENSE-2.0
+%
+% Unless required by applicable law or agreed to in writing, software
+% distributed under the License is distributed on an "AS IS" BASIS,
+% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+% See the License for the specific language governing permissions and
+% limitations under the License.
+%
+% SPDX-License-Identifier: Apache-2.0 OR LGPL-2.1-or-later
+%
+
+-module(bs_get_float_gc).
+
+%% Force the compiler to use bs_get_float2 opcode instead of the
+%% newer bs_match opcode. The no_bs_match option was removed in OTP 29.
+-if(?OTP_RELEASE =< 28).
+-compile([no_bs_match]).
+-endif.
+
+-export([start/0, id/1]).
+
+start() ->
+    Bin = id(<<3.14:64/float, 2.5:32/float>>),
+    Acc = loop(2000, Bin, []),
+    2000 = length(Acc),
+    ok = check(Acc),
+    0.
+
+loop(0, _Bin, Acc) ->
+    Acc;
+loop(N, Bin, Acc) ->
+    <<F64:64/float, F32:32/float>> = Bin,
+    _ = id(make_list(32, [])),
+    loop(N - 1, Bin, [{F64, F32} | Acc]).
+
+make_list(0, Acc) ->
+    Acc;
+make_list(N, Acc) ->
+    make_list(N - 1, [N | Acc]).
+
+check([]) ->
+    ok;
+check([{F64, F32} | Tail]) ->
+    true = (F64 > 3.139) andalso (F64 < 3.141),
+    true = (F32 > 2.49) andalso (F32 < 2.51),
+    check(Tail).
+
+id(X) -> X.

tests/test.c

@@ -536,6 +536,7 @@ struct Test tests[] = {
     TEST_CASE(bs_get_binary_fixed_size),
     TEST_CASE(bs_get_integer_fixed_size),
     TEST_CASE(bs_get_float_dynamic_size),
+    TEST_CASE(bs_get_float_gc),
     TEST_CASE(test_is_not_equal),
     TEST_CASE(test_make_fun2),
     TEST_CASE(test_allocate_zero),