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authorBjörn Gustavsson <[email protected]>2017-09-01 10:52:14 +0200
committerGitHub <[email protected]>2017-09-01 10:52:14 +0200
commitfdf30c9a74871e45fc15004835f96cb1481fa5ca (patch)
treef9a10a1857ca59a2c68f6cec6180a1c8234f0eff
parent2ddc4f3808e9139ca9826c04d0f2829d3bf50b84 (diff)
parent8b8f013dbe159819136e71f0349620ff8fc45f74 (diff)
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Merge pull request #1550 from bjorng/bjorn/erts/unique-literals
De-duplicate bignums in the literal pool
-rw-r--r--erts/emulator/beam/beam_load.c71
1 files changed, 48 insertions, 23 deletions
diff --git a/erts/emulator/beam/beam_load.c b/erts/emulator/beam/beam_load.c
index cc3219989e..7d3a19ff86 100644
--- a/erts/emulator/beam/beam_load.c
+++ b/erts/emulator/beam/beam_load.c
@@ -5352,12 +5352,15 @@ get_tag_and_value(LoaderState* stp, Uint len_code,
{
Uint count;
Sint val;
- byte default_buf[128];
- byte* bigbuf = default_buf;
+ byte default_byte_buf[128];
+ byte* byte_buf = default_byte_buf;
+ Eterm default_big_buf[128/sizeof(Eterm)];
+ Eterm* big_buf = default_big_buf;
+ Eterm tmp_big;
byte* s;
int i;
int neg = 0;
- Uint arity;
+ Uint words_needed;
Eterm* hp;
/*
@@ -5434,8 +5437,11 @@ get_tag_and_value(LoaderState* stp, Uint len_code,
*result = val;
return TAG_i;
} else {
- *result = new_literal(stp, &hp, BIG_UINT_HEAP_SIZE);
- (void) small_to_big(val, hp);
+ tmp_big = small_to_big(val, big_buf);
+ if (!find_literal(stp, tmp_big, result)) {
+ *result = new_literal(stp, &hp, BIG_UINT_HEAP_SIZE);
+ sys_memcpy(hp, big_buf, BIG_UINT_HEAP_SIZE*sizeof(Eterm));
+ }
return TAG_q;
}
}
@@ -5445,8 +5451,8 @@ get_tag_and_value(LoaderState* stp, Uint len_code,
* (including margin).
*/
- if (count+8 > sizeof(default_buf)) {
- bigbuf = erts_alloc(ERTS_ALC_T_LOADER_TMP, count+8);
+ if (count+8 > sizeof(default_byte_buf)) {
+ byte_buf = erts_alloc(ERTS_ALC_T_LOADER_TMP, count+8);
}
/*
@@ -5455,20 +5461,20 @@ get_tag_and_value(LoaderState* stp, Uint len_code,
GetString(stp, s, count);
for (i = 0; i < count; i++) {
- bigbuf[count-i-1] = *s++;
+ byte_buf[count-i-1] = *s++;
}
/*
* Check if the number is negative, and negate it if so.
*/
- if ((bigbuf[count-1] & 0x80) != 0) {
+ if ((byte_buf[count-1] & 0x80) != 0) {
unsigned carry = 1;
neg = 1;
for (i = 0; i < count; i++) {
- bigbuf[i] = ~bigbuf[i] + carry;
- carry = (bigbuf[i] == 0 && carry == 1);
+ byte_buf[i] = ~byte_buf[i] + carry;
+ carry = (byte_buf[i] == 0 && carry == 1);
}
ASSERT(carry == 0);
}
@@ -5477,33 +5483,52 @@ get_tag_and_value(LoaderState* stp, Uint len_code,
* Align to word boundary.
*/
- if (bigbuf[count-1] == 0) {
+ if (byte_buf[count-1] == 0) {
count--;
}
- if (bigbuf[count-1] == 0) {
+ if (byte_buf[count-1] == 0) {
LoadError0(stp, "bignum not normalized");
}
while (count % sizeof(Eterm) != 0) {
- bigbuf[count++] = 0;
+ byte_buf[count++] = 0;
}
/*
- * Allocate heap space for the bignum and copy it.
+ * Convert to a bignum.
*/
- arity = count/sizeof(Eterm);
- *result = new_literal(stp, &hp, arity+1);
- if (is_nil(bytes_to_big(bigbuf, count, neg, hp)))
- goto load_error;
+ words_needed = count/sizeof(Eterm) + 1;
+ if (words_needed*sizeof(Eterm) > sizeof(default_big_buf)) {
+ big_buf = erts_alloc(ERTS_ALC_T_LOADER_TMP, words_needed*sizeof(Eterm));
+ }
+ tmp_big = bytes_to_big(byte_buf, count, neg, big_buf);
+ if (is_nil(tmp_big)) {
+ goto load_error;
+ }
- if (bigbuf != default_buf) {
- erts_free(ERTS_ALC_T_LOADER_TMP, (void *) bigbuf);
+ /*
+ * Create a literal if there is no previous literal with the same value.
+ */
+
+ if (!find_literal(stp, tmp_big, result)) {
+ *result = new_literal(stp, &hp, words_needed);
+ sys_memcpy(hp, big_buf, words_needed*sizeof(Eterm));
+ }
+
+ if (byte_buf != default_byte_buf) {
+ erts_free(ERTS_ALC_T_LOADER_TMP, (void *) byte_buf);
+ }
+ if (big_buf != default_big_buf) {
+ erts_free(ERTS_ALC_T_LOADER_TMP, (void *) big_buf);
}
return TAG_q;
load_error:
- if (bigbuf != default_buf) {
- erts_free(ERTS_ALC_T_LOADER_TMP, (void *) bigbuf);
+ if (byte_buf != default_byte_buf) {
+ erts_free(ERTS_ALC_T_LOADER_TMP, (void *) byte_buf);
+ }
+ if (big_buf != default_big_buf) {
+ erts_free(ERTS_ALC_T_LOADER_TMP, (void *) big_buf);
}
return -1;
}