Implement minimal bigint binary pattern matching

Implement everything needed to run JIT compiler (that uses bigint
pattern matching) on AtomVM.

Some bigint handling parts are not yet implemented, such as =:= binary
pattern matching operation.

Also unsigned 64-bits pattern matching is not yet fixed.

Signed-off-by: Davide Bettio <[email protected]>

Author: bettio

src/libAtomVM/bitstring.c

@@ -406,3 +406,20 @@ bool bitstring_extract_f64(
         return false;
     }
 }
+
+intn_from_integer_options_t bitstring_flags_to_intn_opts(enum BitstringFlags bf)
+{
+    intn_from_integer_options_t converted = IntnUnsignedBigEndian;
+    if (bf & LittleEndianInteger) {
+        converted |= IntnLittleEndian;
+    }
+    if (bf & SignedInteger) {
+        converted |= IntnSigned;
+    }
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+    if (bf & NativeEndianInteger) {
+        converted |= IntnLittleEndian;
+    }
+#endif
+    return converted;
+}

src/libAtomVM/bitstring.h

@@ -22,6 +22,7 @@
 #ifndef _BITSTRING_H_
 #define _BITSTRING_H_
 
+#include "intn.h"
 #include "term.h"
 #include "unicode.h"
 
@@ -528,6 +529,8 @@ bool bitstring_extract_f32(
 bool bitstring_extract_f64(
     term src_bin, size_t offset, avm_int_t n, enum BitstringFlags bs_flags, avm_float_t *dst);
 
+intn_from_integer_options_t bitstring_flags_to_intn_opts(enum BitstringFlags bf);
+
 #ifdef __cplusplus
 }
 #endif

src/libAtomVM/jit.c

@@ -1244,19 +1244,64 @@ static term jit_term_alloc_bin_match_state(Context *ctx, term src, int slots)
     return term_alloc_bin_match_state(src, slots, &ctx->heap);
 }
 
-static term jit_bitstring_extract_integer(Context *ctx, JITState *jit_state, term *bin_ptr, size_t offset, int n, int bs_flags)
+static term extract_bigint(Context *ctx, JITState *jit_state, const uint8_t *bytes,
+    size_t bytes_size, intn_from_integer_options_t opts)
 {
-    TRACE("jit_bitstring_extract_integer: bin_ptr=%p offset=%d n=%d bs_flags=%d\n", (void *) bin_ptr, (int) offset, n, bs_flags);
-    union maybe_unsigned_int64 value;
-    bool status = bitstring_extract_integer(((term) bin_ptr) | TERM_PRIMARY_BOXED, offset, n, bs_flags, &value);
-    if (UNLIKELY(!status)) {
+    intn_integer_sign_t sign;
+    intn_digit_t bigint[INTN_MAX_RES_LEN];
+    int count = intn_from_integer_bytes(bytes, bytes_size, opts, bigint, &sign);
+    // count will be always >= 0, caller ensures that bits <= INTN_MAX_UNSIGNED_BITS_SIZE
+
+    size_t intn_data_size;
+    size_t rounded_res_len;
+    term_bigint_size_requirements(count, &intn_data_size, &rounded_res_len);
+
+    Heap heap;
+    if (UNLIKELY(memory_init_heap(&heap, BOXED_BIGINT_HEAP_SIZE(intn_data_size)) != MEMORY_GC_OK)) {
+        set_error(ctx, jit_state, 0, OUT_OF_MEMORY_ATOM);
         return FALSE_ATOM;
     }
-    term t = maybe_alloc_boxed_integer_fragment(ctx, value.s);
-    if (UNLIKELY(term_is_invalid_term(t))) {
-        set_error(ctx, jit_state, 0, OUT_OF_MEMORY_ATOM);
+
+    term bigint_term
+        = term_create_uninitialized_bigint(intn_data_size, (term_integer_sign_t) sign, &heap);
+    term_initialize_bigint(bigint_term, bigint, count, rounded_res_len);
+
+    memory_heap_append_heap(&ctx->heap, &heap);
+
+    return bigint_term;
+}
+
+static term jit_bitstring_extract_integer(
+    Context *ctx, JITState *jit_state, term *bin_ptr, size_t offset, int n, int bs_flags)
+{
+    TRACE("jit_bitstring_extract_integer: bin_ptr=%p offset=%d n=%d bs_flags=%d\n",
+        (void *) bin_ptr, (int) offset, n, bs_flags);
+    if (n <= 64) {
+        union maybe_unsigned_int64 value;
+        bool status = bitstring_extract_integer(
+            ((term) bin_ptr) | TERM_PRIMARY_BOXED, offset, n, bs_flags, &value);
+        if (UNLIKELY(!status)) {
+            return FALSE_ATOM;
+        }
+        term t = maybe_alloc_boxed_integer_fragment(ctx, value.s);
+        if (UNLIKELY(term_is_invalid_term(t))) {
+            set_error(ctx, jit_state, 0, OUT_OF_MEMORY_ATOM);
+        }
+        return t;
+    } else if ((offset % 8 == 0) && (n % 8 == 0) && (n <= INTN_MAX_UNSIGNED_BITS_SIZE)) {
+        term bs_bin = ((term) bin_ptr) | TERM_PRIMARY_BOXED;
+        unsigned long capacity = term_binary_size(bs_bin);
+        if (8 * capacity - offset < (unsigned long) n) {
+            return FALSE_ATOM;
+        }
+        size_t byte_offset = offset / 8;
+        const uint8_t *int_bytes = (const uint8_t *) term_binary_data(bs_bin);
+
+        return extract_bigint(
+            ctx, jit_state, int_bytes + byte_offset, n / 8, bitstring_flags_to_intn_opts(bs_flags));
+    } else {
+        return FALSE_ATOM;
     }
-    return t;
 }
 
 static term jit_bitstring_extract_float(Context *ctx, term *bin_ptr, size_t offset, int n, int bs_flags)

src/libAtomVM/opcodesswitch.h

@@ -1814,6 +1814,40 @@ static bool maybe_call_native(Context *ctx, atom_index_t module_name, atom_index
 #endif
 
 #ifndef AVM_NO_EMU
+    static term extract_nbits_integer(Context *ctx, const uint8_t *bytes, size_t bytes_size, intn_from_integer_options_t opts)
+    {
+        intn_integer_sign_t sign;
+        intn_digit_t bigint[INTN_MAX_RES_LEN];
+        int count = intn_from_integer_bytes(bytes, bytes_size, opts, bigint, &sign);
+        if (UNLIKELY(count < 0)) {
+            // this is likely unreachable, compiler seem to generate an external term
+            // and to encode this as SMALL_BIG_EXT, so I don't think this code is executed
+            ctx->x[0] = ERROR_ATOM;
+            ctx->x[1] = OVERFLOW_ATOM;
+            return term_invalid_term();
+        }
+
+        size_t intn_data_size;
+        size_t rounded_res_len;
+        term_bigint_size_requirements(count, &intn_data_size, &rounded_res_len);
+
+        Heap heap;
+        if (UNLIKELY(
+                memory_init_heap(&heap, BOXED_BIGINT_HEAP_SIZE(intn_data_size)) != MEMORY_GC_OK)) {
+            ctx->x[0] = ERROR_ATOM;
+            ctx->x[1] = OUT_OF_MEMORY_ATOM;
+            return term_invalid_term();
+        }
+
+        term bigint_term
+            = term_create_uninitialized_bigint(intn_data_size, (term_integer_sign_t) sign, &heap);
+        term_initialize_bigint(bigint_term, bigint, count, rounded_res_len);
+
+        memory_heap_append_heap(&ctx->heap, &heap);
+
+        return bigint_term;
+    }
+
     static size_t decode_nbits_integer(Context *ctx, const uint8_t *encoded, term *out_term)
     {
         const uint8_t *new_encoded = encoded;
@@ -1826,41 +1860,9 @@ static bool maybe_call_native(Context *ctx, atom_index_t module_name, atom_index
         len += 9;
 
         if (out_term) {
-            intn_integer_sign_t sign;
-            intn_digit_t bigint[INTN_MAX_RES_LEN];
-            int count = intn_from_integer_bytes(new_encoded, len, IntnSigned, bigint, &sign);
-            if (UNLIKELY(count < 0)) {
-                // this is likely unreachable, compiler seem to generate an external term
-                // and to encode this as SMALL_BIG_EXT, so I don't think this code is executed
-                ctx->x[0] = ERROR_ATOM;
-                ctx->x[1] = OVERFLOW_ATOM;
-                *out_term = term_invalid_term();
-                goto return_size;
-            }
-
-            size_t intn_data_size;
-            size_t rounded_res_len;
-            term_bigint_size_requirements(count, &intn_data_size, &rounded_res_len);
-
-            Heap heap;
-            if (UNLIKELY(
-                    memory_init_heap(&heap, BOXED_BIGINT_HEAP_SIZE(intn_data_size)) != MEMORY_GC_OK)) {
-                ctx->x[0] = ERROR_ATOM;
-                ctx->x[1] = OUT_OF_MEMORY_ATOM;
-                *out_term = term_invalid_term();
-                goto return_size;
-            }
-
-            term bigint_term
-                = term_create_uninitialized_bigint(intn_data_size, (term_integer_sign_t) sign, &heap);
-            term_initialize_bigint(bigint_term, bigint, count, rounded_res_len);
-
-            memory_heap_append_heap(&ctx->heap, &heap);
-
-            *out_term = bigint_term;
+            *out_term = extract_nbits_integer(ctx, new_encoded, len, IntnSigned);
         }
 
-    return_size:
         return (new_encoded - encoded) + len;
     }
 #endif
@@ -5298,25 +5300,44 @@ HOT_FUNC int scheduler_entry_point(GlobalContext *glb)
                     union maybe_unsigned_int64 value;
                     term bs_bin = term_get_match_state_binary(src);
                     avm_int_t bs_offset = term_get_match_state_offset(src);
-                    bool status = bitstring_extract_integer(bs_bin, bs_offset, increment, flags_value, &value);
-                    if (UNLIKELY(!status)) {
-                        TRACE("bs_get_integer2: error extracting integer.\n");
-                        JUMP_TO_ADDRESS(mod->labels[fail]);
-                    } else {
-                        term_set_match_state_offset(src, bs_offset + increment);
+                    term t;
+                    if (increment <= 64) {
+                        bool status = bitstring_extract_integer(bs_bin, bs_offset, increment, flags_value, &value);
+                        if (UNLIKELY(!status)) {
+                            TRACE("bs_get_integer2: error extracting integer.\n");
+                            JUMP_TO_ADDRESS(mod->labels[fail]);
+                        } else {
+                            term_set_match_state_offset(src, bs_offset + increment);
 
-                        term t = maybe_alloc_boxed_integer_fragment(ctx, value.s);
-                        if (UNLIKELY(term_is_invalid_term(t))) {
+                            t = maybe_alloc_boxed_integer_fragment(ctx, value.s);
+                            if (UNLIKELY(term_is_invalid_term(t))) {
+                                HANDLE_ERROR();
+                            }
+                        }
+                    } else if ((bs_offset % 8 == 0) && (increment % 8 == 0) && (increment <= INTN_MAX_UNSIGNED_BITS_SIZE)) {
+                        unsigned long capacity = term_binary_size(bs_bin);
+                        if (8 * capacity - bs_offset < (unsigned long) increment) {
+                            JUMP_TO_ADDRESS(mod->labels[fail]);
+                        }
+                        size_t byte_offset = bs_offset / 8;
+                        const uint8_t *int_bytes = (const uint8_t *) term_binary_data(bs_bin);
+
+                        t = extract_nbits_integer(ctx, int_bytes + byte_offset, increment / 8,
+                            bitstring_flags_to_intn_opts(flags_value));
+                        term_set_match_state_offset(src, bs_offset + increment);
+                        if (term_is_invalid_term(t)) {
                             HANDLE_ERROR();
                         }
+                    } else {
+                        JUMP_TO_ADDRESS(mod->labels[fail]);
+                    }
                 #endif
 
                 DEST_REGISTER(dreg);
                 DECODE_DEST_REGISTER(dreg, pc);
 
                 #ifdef IMPL_EXECUTE_LOOP
-                        WRITE_REGISTER(dreg, t);
-                    }
+                    WRITE_REGISTER(dreg, t);
                 #endif
                 break;
             }
@@ -7273,15 +7294,35 @@ HOT_FUNC int scheduler_entry_point(GlobalContext *glb)
                                 avm_int_t size_val = term_to_int(size);
                                 avm_int_t increment = size_val * unit;
                                 union maybe_unsigned_int64 value;
-                                bool status = bitstring_extract_integer(bs_bin, bs_offset, increment, flags_value, &value);
-                                if (UNLIKELY(!status)) {
-                                    TRACE("bs_match/3: error extracting integer.\n");
+                                term t;
+                                if (increment <= 64) {
+                                    bool status = bitstring_extract_integer(bs_bin, bs_offset, increment, flags_value, &value);
+                                    if (UNLIKELY(!status)) {
+                                        TRACE("bs_match/3: error extracting integer.\n");
+                                        goto bs_match_jump_to_fail;
+                                    }
+                                    //FIXME: handling of 64-bit unsigned integers is not reliable
+                                    t = maybe_alloc_boxed_integer_fragment(ctx, value.s);
+                                    if (UNLIKELY(term_is_invalid_term(t))) {
+                                        RAISE_ERROR(OUT_OF_MEMORY_ATOM);
+                                    }
+                                } else if ((bs_offset % 8 == 0) && (increment % 8 == 0) && (increment <= INTN_MAX_UNSIGNED_BITS_SIZE)) {
+                                    unsigned long capacity = term_binary_size(bs_bin);
+                                    if (8 * capacity - bs_offset < (unsigned long) increment) {
+                                        goto bs_match_jump_to_fail;
+                                    }
+                                    size_t byte_offset = bs_offset / 8;
+                                    const uint8_t *int_bytes
+                                        = (const uint8_t *) term_binary_data(bs_bin);
+
+                                    t = extract_nbits_integer(ctx, int_bytes + byte_offset,
+                                        increment / 8, bitstring_flags_to_intn_opts(flags_value));
+                                    if (term_is_invalid_term(t)) {
+                                        HANDLE_ERROR();
+                                    }
+                                } else {
                                     goto bs_match_jump_to_fail;
                                 }
-                                term t = maybe_alloc_boxed_integer_fragment(ctx, value.s);
-                                if (UNLIKELY(term_is_invalid_term(t))) {
-                                    RAISE_ERROR(OUT_OF_MEMORY_ATOM);
-                                }
                             #endif
                             DEST_REGISTER(dreg);
                             DECODE_DEST_REGISTER(dreg, pc);
@@ -7388,6 +7429,10 @@ HOT_FUNC int scheduler_entry_point(GlobalContext *glb)
                             DECODE_LITERAL(pattern_value, pc);
                             j++;
                             #ifdef IMPL_EXECUTE_LOOP
+                                if (size > 64) {
+                                    // TODO: implement support for big integers also here
+                                    RAISE_ERROR(BADARG_ATOM);
+                                }
                                 union maybe_unsigned_int64 matched_value;
                                 bool status = bitstring_extract_integer(bs_bin, bs_offset, size, 0, &matched_value);
                                 if (UNLIKELY(!status)) {

tests/erlang_tests/bigint.erl

@@ -72,6 +72,7 @@ start() ->
         test_is_number() +
         test_gt_lt_guards() +
         to_external_term() +
+        test_pattern_match() +
         test_band() +
         test_bxor() +
         test_bor() +
@@ -2138,6 +2139,44 @@ to_external_term() ->
 
     0.
 
+test_pattern_match() ->
+    <<Int72:72/integer-little-signed>> = ?MODULE:id(<<23, 4, 222, 66, 172, 197, 113, 183, 80>>),
+    <<"50B771C5AC42DE0417">> = erlang:integer_to_binary(?MODULE:id(Int72), 16),
+    <<Int80:80/integer-little-signed>> = ?MODULE:id(
+        <<165, 63, 196, 58, 33, 96, 209, 59, 244, 213>>
+    ),
+    <<"-2A0BC42E9FDEC53BC05B">> = erlang:integer_to_binary(?MODULE:id(Int80), 16),
+    <<Int120:120/unsigned-big-integer>> = ?MODULE:id(
+        <<0, 242, 138, 221, 68, 111, 58, 120, 145, 135, 164, 56, 164, 12, 205>>
+    ),
+    <<"F28ADD446F3A789187A438A40CCD">> = erlang:integer_to_binary(?MODULE:id(Int120), 16),
+    <<Int256:256/unsigned-big-integer>> = ?MODULE:id(
+        <<202, 196, 64, 150, 63, 238, 50, 47, 214, 81, 247, 55, 151, 242, 169, 106, 162, 211, 73,
+            155, 211, 85, 164, 237, 153, 138, 191, 77, 87, 183, 204, 111>>
+    ),
+    <<"CAC440963FEE322FD651F73797F2A96AA2D3499BD355A4ED998ABF4D57B7CC6F">> = erlang:integer_to_binary(
+        ?MODULE:id(Int256), 16
+    ),
+
+    <<"foo", Int128:128/unsigned-little-integer, Bar/binary>> = ?MODULE:id(
+        <<102, 111, 111, 183, 226, 155, 102, 249, 246, 168, 101, 53, 36, 21, 10, 133, 223, 231, 10,
+            98, 97, 114>>
+    ),
+    <<"AE7DF850A15243565A8F6F9669BE2B7">> = erlang:integer_to_binary(?MODULE:id(Int128), 16),
+    <<"bar">> = ?MODULE:id(Bar),
+
+    ok =
+        case
+            ?MODULE:id(
+                <<102, 111, 111, 183, 226, 155, 102, 249, 246, 168, 101, 53, 36, 21, 10, 133, 223,
+                    231>>
+            )
+        of
+            <<"foo", _I128:128/unsigned-little-integer, Bar/binary>> -> error;
+            _ -> ok
+        end,
+    0.
+
 test_band() ->
     MaxPatternBin = <<"FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF">>,
     MaxPattern = erlang:binary_to_integer(?MODULE:id(MaxPatternBin), 16),