https://gcc.gnu.org/g:96ba5e5663d4390a7e69735ce3c9de657fc543fc
commit r15-4402-g96ba5e5663d4390a7e69735ce3c9de657fc543fc
Author: Jakub Jelinek <ja...@redhat.com>
Date: Thu Oct 17 06:59:31 2024 +0200
c: Fix up speed up compilation of large char array initializers when not
using #embed [PR117177]
Apparently my
c: Speed up compilation of large char array initializers when not using
#embed
patch broke building glibc.
The issue is that when using CPP_EMBED, we are guaranteed by the
preprocessor that there is CPP_NUMBER CPP_COMMA before it and
CPP_COMMA CPP_NUMBER after it (or CPP_COMMA CPP_EMBED), so RAW_DATA_CST
never ends up at the end of arrays of unknown length.
Now, the c_parser_initval optimization attempted to preserve that property
rather than changing everything that e.g. inferes array number of elements
from the initializer etc. to deal with RAW_DATA_CST at the end, but
it didn't take into account the possibility that there could be
CPP_COMMA followed by CPP_CLOSE_BRACE (where the CPP_COMMA is redundant).
As we are peaking already at 4 tokens in that code, peeking more would
require using raw tokens and that seems to be expensive doing it for
every pair of tokens due to vec_free done when we are out of raw tokens.
So, the following patch instead determines the case where we want
another INTEGER_CST element after it after consuming the tokens, and just
arranges for another process_init_element.
2024-10-17 Jakub Jelinek <ja...@redhat.com>
PR c/117177
gcc/c/
* c-parser.cc (c_parser_initval): Instead of doing
orig_len == INT_MAX checks before consuming tokens to set
last = 1, check it after consuming it and if not followed
by CPP_COMMA CPP_NUMBER, call process_init_element once
more with the last CPP_NUMBER.
gcc/testsuite/
* c-c++-common/init-4.c: New test.
Diff:
---
gcc/c/c-parser.cc | 35 +++++++++----
gcc/testsuite/c-c++-common/init-4.c | 97 +++++++++++++++++++++++++++++++++++++
2 files changed, 122 insertions(+), 10 deletions(-)
diff --git a/gcc/c/c-parser.cc b/gcc/c/c-parser.cc
index e4381044e5cb..090ab1cbc088 100644
--- a/gcc/c/c-parser.cc
+++ b/gcc/c/c-parser.cc
@@ -6529,6 +6529,7 @@ c_parser_initval (c_parser *parser, struct c_expr *after,
unsigned int i;
gcc_checking_assert (len >= 64);
location_t last_loc = UNKNOWN_LOCATION;
+ location_t prev_loc = UNKNOWN_LOCATION;
for (i = 0; i < 64; ++i)
{
c_token *tok = c_parser_peek_nth_token_raw (parser, 1 + 2 * i);
@@ -6544,6 +6545,7 @@ c_parser_initval (c_parser *parser, struct c_expr *after,
buf1[i] = (char) tree_to_uhwi (tok->value);
if (i == 0)
loc = tok->location;
+ prev_loc = last_loc;
last_loc = tok->location;
}
if (i < 64)
@@ -6567,6 +6569,7 @@ c_parser_initval (c_parser *parser, struct c_expr *after,
unsigned int max_len = 131072 - offsetof (struct tree_string, str) - 1;
unsigned int orig_len = len;
unsigned int off = 0, last = 0;
+ unsigned char lastc = 0;
if (!wi::neg_p (wi::to_wide (val)) && wi::to_widest (val) <= UCHAR_MAX)
off = 1;
len = MIN (len, max_len - off);
@@ -6596,20 +6599,25 @@ c_parser_initval (c_parser *parser, struct c_expr
*after,
if (tok2->type != CPP_COMMA && tok2->type != CPP_CLOSE_BRACE)
break;
buf2[i + off] = (char) tree_to_uhwi (tok->value);
- /* If orig_len is INT_MAX, this can be flexible array member and
- in that case we need to ensure another element which
- for CPP_EMBED is normally guaranteed after it. Include
- that byte in the RAW_DATA_OWNER though, so it can be optimized
- later. */
- if (tok2->type == CPP_CLOSE_BRACE && orig_len == INT_MAX)
- {
- last = 1;
- break;
- }
+ prev_loc = last_loc;
last_loc = tok->location;
c_parser_consume_token (parser);
c_parser_consume_token (parser);
}
+ /* If orig_len is INT_MAX, this can be flexible array member and
+ in that case we need to ensure another element which
+ for CPP_EMBED is normally guaranteed after it. Include
+ that byte in the RAW_DATA_OWNER though, so it can be optimized
+ later. */
+ if (orig_len == INT_MAX
+ && (!c_parser_next_token_is (parser, CPP_COMMA)
+ || c_parser_peek_2nd_token (parser)->type != CPP_NUMBER))
+ {
+ --i;
+ last = 1;
+ std::swap (prev_loc, last_loc);
+ lastc = (unsigned char) buf2[i + off];
+ }
val = make_node (RAW_DATA_CST);
TREE_TYPE (val) = integer_type_node;
RAW_DATA_LENGTH (val) = i;
@@ -6625,6 +6633,13 @@ c_parser_initval (c_parser *parser, struct c_expr *after,
init.original_type = integer_type_node;
init.m_decimal = 0;
process_init_element (loc, init, false, braced_init_obstack);
+ if (last)
+ {
+ init.value = build_int_cst (integer_type_node, lastc);
+ init.original_code = INTEGER_CST;
+ set_c_expr_source_range (&init, prev_loc, prev_loc);
+ process_init_element (prev_loc, init, false, braced_init_obstack);
+ }
}
}
diff --git a/gcc/testsuite/c-c++-common/init-4.c
b/gcc/testsuite/c-c++-common/init-4.c
new file mode 100644
index 000000000000..d575a3f5a513
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/init-4.c
@@ -0,0 +1,97 @@
+/* { dg-do run } */
+/* { dg-options "-O2" } */
+
+unsigned char a1[] = {
+ 0xc8, 0xc9, 0xca, 0xcb, 0x00, 0xcd, 0xce, 0xcf,
+ 0x00, 0xd1, 0x00, 0xd3, 0xd4, 0x00, 0xd6, 0xd7,
+ 0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0x00, 0x00, 0xdf,
+ 0xe0, 0xe1, 0xe2, 0x00, 0xe4, 0xe5, 0xe6, 0xe7,
+ 0xe8, 0xe9, 0xea, 0xeb, 0x00, 0xed, 0xee, 0xef,
+ 0x00, 0xf1, 0x00, 0xf3, 0xf4, 0x00, 0xf6, 0xf7,
+ 0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0x00, 0x00, 0xff,
+ 0x00, 0x00, 0xc3, 0xe3, 0x00, 0x00, 0x00, 0x00,
+ 0xfa, 0xfb, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+};
+unsigned char a2[] = {
+ 0xc8, 0xc9, 0xca, 0xcb, 0x00, 0xcd, 0xce, 0xcf,
+ 0x00, 0xd1, 0x00, 0xd3, 0xd4, 0x00, 0xd6, 0xd7,
+ 0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0x00, 0x00, 0xdf,
+ 0xe0, 0xe1, 0xe2, 0x00, 0xe4, 0xe5, 0xe6, 0xe7,
+ 0xe8, 0xe9, 0xea, 0xeb, 0x00, 0xed, 0xee, 0xef,
+ 0x00, 0xf1, 0x00, 0xf3, 0xf4, 0x00, 0xf6, 0xf7,
+ 0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0x00, 0x00, 0xff,
+ 0x00, 0x00, 0xc3, 0xe3, 0x00, 0x00, 0x00, 0x00
+};
+unsigned char a3[] = {
+ 0xc8, 0xc9, 0xca, 0xcb, 0x00, 0xcd, 0xce, 0xcf,
+ 0x00, 0xd1, 0x00, 0xd3, 0xd4, 0x00, 0xd6, 0xd7,
+ 0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0x00, 0x00, 0xdf,
+ 0xe0, 0xe1, 0xe2, 0x00, 0xe4, 0xe5, 0xe6, 0xe7,
+ 0xe8, 0xe9, 0xea, 0xeb, 0x00, 0xed, 0xee, 0xef,
+ 0x00, 0xf1, 0x00, 0xf3, 0xf4, 0x00, 0xf6, 0xf7,
+ 0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0x00, 0x00, 0xff,
+ 0x00, 0x00, 0xc3, 0xe3, 0x00, 0x00, 0x00, 0x00,
+};
+unsigned char a4[] = {
+ 0xc8, 0xc9, 0xca, 0xcb, 0x00, 0xcd, 0xce, 0xcf,
+ 0x00, 0xd1, 0x00, 0xd3, 0xd4, 0x00, 0xd6, 0xd7,
+ 0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0x00, 0x00, 0xdf,
+ 0xe0, 0xe1, 0xe2, 0x00, 0xe4, 0xe5, 0xe6, 0xe7,
+ 0xe8, 0xe9, 0xea, 0xeb, 0x00, 0xed, 0xee, 0xef,
+ 0x00, 0xf1, 0x00, 0xf3, 0xf4, 0x00, 0xf6, 0xf7,
+ 0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0x00, 0x00, 0xff,
+ 0x00, 0x00, 0xc3, 0xe3, 0x00, 0x00, 0x00, 0x00,
+ 0xfa
+};
+unsigned char a5[] = {
+ 0xc8, 0xc9, 0xca, 0xcb, 0x00, 0xcd, 0xce, 0xcf,
+ 0x00, 0xd1, 0x00, 0xd3, 0xd4, 0x00, 0xd6, 0xd7,
+ 0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0x00, 0x00, 0xdf,
+ 0xe0, 0xe1, 0xe2, 0x00, 0xe4, 0xe5, 0xe6, 0xe7,
+ 0xe8, 0xe9, 0xea, 0xeb, 0x00, 0xed, 0xee, 0xef,
+ 0x00, 0xf1, 0x00, 0xf3, 0xf4, 0x00, 0xf6, 0xf7,
+ 0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0x00, 0x00, 0xff,
+ 0x00, 0x00, 0xc3, 0xe3, 0x00, 0x00, 0x00, 0x00,
+ 0xfa,
+};
+unsigned char a6[] = {
+ 0xc8, 0xc9, 0xca, 0xcb, 0x00, 0xcd, 0xce, 0xcf,
+ 0x00, 0xd1, 0x00, 0xd3, 0xd4, 0x00, 0xd6, 0xd7,
+ 0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0x00, 0x00, 0xdf,
+ 0xe0, 0xe1, 0xe2, 0x00, 0xe4, 0xe5, 0xe6, 0xe7,
+ 0xe8, 0xe9, 0xea, 0xeb, 0x00, 0xed, 0xee, 0xef,
+ 0x00, 0xf1, 0x00, 0xf3, 0xf4, 0x00, 0xf6, 0xf7,
+ 0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0x00, 0x00, 0xff,
+ 0x00, 0x00, 0xc3, 0xe3, 0x00, 0x00, 0x00, 0x00,
+ 0xfa, 0xfb
+};
+unsigned char a7[] = {
+ 0xc8, 0xc9, 0xca, 0xcb, 0x00, 0xcd, 0xce, 0xcf,
+ 0x00, 0xd1, 0x00, 0xd3, 0xd4, 0x00, 0xd6, 0xd7,
+ 0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0x00, 0x00, 0xdf,
+ 0xe0, 0xe1, 0xe2, 0x00, 0xe4, 0xe5, 0xe6, 0xe7,
+ 0xe8, 0xe9, 0xea, 0xeb, 0x00, 0xed, 0xee, 0xef,
+ 0x00, 0xf1, 0x00, 0xf3, 0xf4, 0x00, 0xf6, 0xf7,
+ 0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0x00, 0x00, 0xff,
+ 0x00, 0x00, 0xc3, 0xe3, 0x00, 0x00, 0x00, 0x00,
+ 0xfa, 0xfb
+};
+
+int
+main ()
+{
+ if (sizeof (a1) != 72
+ || sizeof (a2) != 64
+ || __builtin_memcmp (a1, a2, 64) != 0
+ || sizeof (a3) != 64
+ || __builtin_memcmp (a1, a3, 64) != 0
+ || sizeof (a4) != 65
+ || __builtin_memcmp (a1, a4, 65) != 0
+ || sizeof (a5) != 65
+ || __builtin_memcmp (a1, a5, 65) != 0
+ || sizeof (a6) != 66
+ || __builtin_memcmp (a1, a6, 66) != 0
+ || sizeof (a7) != 66
+ || __builtin_memcmp (a1, a7, 66) != 0)
+ __builtin_abort ();
+}
