Hi.
I've returned to this long-lasting issue after quite some time. Thanks to Honza
I hope
I can now address the root cause which caused output of a string constant when
debug info
was emitted. The problematic situation happened with following back-trace:
#0 mergeable_string_section (decl=<string_cst 0x7ffff67be210>, align=64,
flags=0) at /home/marxin/Programming/gcc/gcc/varasm.c:808
#1 0x0000000001779bf3 in default_elf_select_section (decl=<string_cst
0x7ffff67be210>, reloc=0, align=64) at
/home/marxin/Programming/gcc/gcc/varasm.c:6739
#2 0x000000000176efb6 in get_constant_section (exp=<string_cst
0x7ffff67be210>, align=64) at /home/marxin/Programming/gcc/gcc/varasm.c:3302
#3 0x000000000176f468 in build_constant_desc (exp=<string_cst 0x7ffff67be210>)
at /home/marxin/Programming/gcc/gcc/varasm.c:3371
#4 0x000000000176f81c in output_constant_def (exp=<string_cst 0x7ffff67be210>,
defer=1) at /home/marxin/Programming/gcc/gcc/varasm.c:3434
#5 0x000000000176d406 in decode_addr_const (exp=<addr_expr 0x7ffff682f8c0>,
value=0x7fffffffc540) at /home/marxin/Programming/gcc/gcc/varasm.c:2951
#6 0x000000000176d93f in const_hash_1 (exp=<addr_expr 0x7ffff682f8c0>) at
/home/marxin/Programming/gcc/gcc/varasm.c:3054
#7 0x000000000176fdc2 in lookup_constant_def (exp=<addr_expr 0x7ffff682f8c0>)
at /home/marxin/Programming/gcc/gcc/varasm.c:3557
#8 0x0000000000dd5778 in cst_pool_loc_descr (loc=<addr_expr 0x7ffff682f8c0>)
at /home/marxin/Programming/gcc/gcc/dwarf2out.c:17288
That was in situation where we emit debug info of a function that has an
inlined __PRETTY_FUNCTION__ from
a different function. As seen, the constant is output due to const_hash_1
function call. Proper fix would
be to not emit these string constants for purpose of hash function.
However, I still see some minor ICEs, it's probably related to decay_conversion
in cp_fname_init:
1) ./xg++ -B.
/home/marxin/Programming/gcc/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-__func__2.C
/home/marxin/Programming/gcc/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-__func__2.C:6:17:
internal compiler error: Segmentation fault
6 | [] { return __func__; }();
| ^~~~~~~~
0x1344568 crash_signal
/home/marxin/Programming/gcc/gcc/toplev.c:325
0x7ffff6bc310f ???
/usr/src/debug/glibc-2.27-6.1.x86_64/signal/../sysdeps/unix/sysv/linux/x86_64/sigaction.c:0
0x9db134 is_capture_proxy(tree_node*)
/home/marxin/Programming/gcc/gcc/cp/lambda.c:261
0xaeecb7 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
/home/marxin/Programming/gcc/gcc/cp/pt.c:16700
0xaee5fd tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
/home/marxin/Programming/gcc/gcc/cp/pt.c:16636
0xaf0ffb tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
/home/marxin/Programming/gcc/gcc/cp/pt.c:16942
where
(gdb) p debug_tree(decl)
<var_decl 0x7ffff7fee480 __func__
type <pointer_type 0x7ffff69b5540
type <integer_type 0x7ffff69b5498 char readonly unsigned string-flag
type_6 QI
size <integer_cst 0x7ffff698df78 constant 8>
unit-size <integer_cst 0x7ffff698df90 constant 1>
align:8 warn_if_not_align:0 symtab:0 alias-set -1 canonical-type
0x7ffff69b5498 precision:8 min <integer_cst 0x7ffff698dfd8 0> max <integer_cst
0x7ffff698dfc0 255>
pointer_to_this <pointer_type 0x7ffff69b5540>>
unsigned DI
size <integer_cst 0x7ffff698de88 constant 64>
unit-size <integer_cst 0x7ffff698dea0 constant 8>
align:64 warn_if_not_align:0 symtab:0 alias-set -1 canonical-type
0x7ffff69b5540>
readonly used tree_2 unsigned DI
/home/marxin/Programming/gcc/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-__func__2.C:6:17
size <integer_cst 0x7ffff698de88 64> unit-size <integer_cst 0x7ffff698dea0 8>
align:64 warn_if_not_align:0 context <function_decl 0x7ffff67abd00
operator()>
value-expr <nop_expr 0x7ffff67b7660 type <pointer_type 0x7ffff69b5540>
constant
arg:0 <addr_expr 0x7ffff67b7640 type <pointer_type 0x7ffff67bd3f0>
constant
arg:0 <string_cst 0x7ffff67b7620 type <array_type 0x7ffff67bd348>
constant "operator()\000">>>>
and
#0 0x00000000009db134 in is_capture_proxy (decl=<tree 0x0>) at
/home/marxin/Programming/gcc/gcc/cp/lambda.c:261
2 ) ./xg++ -B. /home/marxin/Programming/gcc/gcc/testsuite/g++.dg/ext/pretty2.C
-c
/home/marxin/Programming/gcc/gcc/testsuite/g++.dg/ext/pretty2.C:16:24: internal
compiler error: Segmentation fault
16 | __PRETTY_FUNCTION__), 0))
| ^
/home/marxin/Programming/gcc/gcc/testsuite/g++.dg/ext/pretty2.C:36:10: note: in
expansion of macro ‘assert’
36 | int a = (assert (foo ()), 1);
| ^~~~~~
0x1344568 crash_signal
/home/marxin/Programming/gcc/gcc/toplev.c:325
0x7ffff6bc310f ???
/usr/src/debug/glibc-2.27-6.1.x86_64/signal/../sysdeps/unix/sysv/linux/x86_64/sigaction.c:0
0x9db270 is_capture_proxy(tree_node*)
/home/marxin/Programming/gcc/gcc/cp/lambda.c:265
0x9dbad9 is_normal_capture_proxy(tree_node*)
/home/marxin/Programming/gcc/gcc/cp/lambda.c:274
0x9c1fe6 mark_use(tree_node*, bool, bool, unsigned int, bool)
/home/marxin/Programming/gcc/gcc/cp/expr.c:114
0x89d9ab convert_like_real
/home/marxin/Programming/gcc/gcc/cp/call.c:6905
where:
(gdb) p debug_tree(decl)
<var_decl 0x7ffff7fee870 __PRETTY_FUNCTION__
type <pointer_type 0x7ffff69b4540
type <integer_type 0x7ffff69b4498 char readonly unsigned string-flag
type_6 QI
size <integer_cst 0x7ffff698df78 constant 8>
unit-size <integer_cst 0x7ffff698df90 constant 1>
align:8 warn_if_not_align:0 symtab:0 alias-set -1 canonical-type
0x7ffff69b4498 precision:8 min <integer_cst 0x7ffff698dfd8 0> max <integer_cst
0x7ffff698dfc0 255>
pointer_to_this <pointer_type 0x7ffff69b4540>>
unsigned type_6 DI
size <integer_cst 0x7ffff698de88 constant 64>
unit-size <integer_cst 0x7ffff698dea0 constant 8>
align:64 warn_if_not_align:0 symtab:0 alias-set -1 canonical-type
0x7ffff69b4540>
readonly used tree_1 tree_2 unsigned read decl_6 DI
/home/marxin/Programming/gcc/gcc/testsuite/g++.dg/ext/pretty2.C:36:10 size
<integer_cst 0x7ffff698de88 64> unit-size <integer_cst 0x7ffff698dea0 8>
align:64 warn_if_not_align:0
value-expr <nop_expr 0x7ffff67b69a0 type <pointer_type 0x7ffff69b4540>
constant
arg:0 <addr_expr 0x7ffff67b6980 type <pointer_type 0x7ffff67c3738>
constant
arg:0 <string_cst 0x7ffff67b6960 type <array_type 0x7ffff67c3690>
constant "top level\000">>> chain <var_decl 0x7ffff7fee7e0 a>>
Can please a C++ maintainer help me with that? Having that I hope I can finish
the patch.
Thank you,
Martin
>From 19db91a83ef40cbe8ca598fb397ee9a9fd8155eb Mon Sep 17 00:00:00 2001
From: marxin <mli...@suse.cz>
Date: Thu, 4 Oct 2018 15:34:51 +0200
Subject: [PATCH] Make __PRETTY_FUNCTION__-like functions mergeable string csts
(PR c++/64266).
gcc/ChangeLog:
2018-10-22 Martin Liska <mli...@suse.cz>
PR c++/64266
PR bootstrap/70422
* varasm.c (decode_addr_const): Add new argument build.
(const_hash_1): Set build to false by default.
(lookup_constant_def): Do not build by default.
gcc/cp/ChangeLog:
2018-10-22 Martin Liska <mli...@suse.cz>
PR c++/64266
PR bootstrap/70422
* decl.c (cp_fname_init): Decay the initializer to pointer.
(cp_make_fname_decl): Set DECL_DECLARED_CONSTEXPR_P,
DECL_VALUE_EXPR, DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P.
Don't call cp_finish_decl.
* pt.c (tsubst_expr): Set DECL_VALUE_EXPR,
DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P. Don't call cp_finish_decl.
gcc/testsuite/ChangeLog:
2018-10-22 Martin Liska <mli...@suse.cz>
PR c++/64266
PR bootstrap/70422
* g++.dg/cpp0x/constexpr-__func__2.C (main):
(SA): Make it static assert.
* g++.old-deja/g++.ext/pretty4.C: Remove.
---
gcc/cp/decl.c | 23 +++--
gcc/cp/pt.c | 25 +++---
.../g++.dg/cpp0x/constexpr-__func__2.C | 7 +-
gcc/testsuite/g++.old-deja/g++.ext/pretty4.C | 85 -------------------
gcc/varasm.c | 43 ++++++----
5 files changed, 62 insertions(+), 121 deletions(-)
delete mode 100644 gcc/testsuite/g++.old-deja/g++.ext/pretty4.C
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 2d9d56ef6e1..13167582266 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -4445,13 +4445,15 @@ cp_fname_init (const char* name, tree *type_p)
type = cp_build_qualified_type (char_type_node, TYPE_QUAL_CONST);
type = build_cplus_array_type (type, domain);
- *type_p = type;
+ *type_p = type_decays_to (type);
if (init)
TREE_TYPE (init) = type;
else
init = error_mark_node;
+ init = decay_conversion (init, tf_warning_or_error);
+
return init;
}
@@ -4474,23 +4476,34 @@ cp_make_fname_decl (location_t loc, tree id, int type_dep)
if (name)
free (CONST_CAST (char *, name));
- TREE_STATIC (decl) = 1;
+ /* As we're using pushdecl_with_scope, we must set the context. */
+ DECL_CONTEXT (decl) = current_function_decl;
+
TREE_READONLY (decl) = 1;
DECL_ARTIFICIAL (decl) = 1;
+ DECL_DECLARED_CONSTEXPR_P (decl) = 1;
TREE_USED (decl) = 1;
+ if (init)
+ {
+ SET_DECL_VALUE_EXPR (decl, init);
+ DECL_HAS_VALUE_EXPR_P (decl) = 1;
+ /* For decl_constant_var_p. */
+ DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (decl) = 1;
+ }
+
if (current_function_decl)
{
DECL_CONTEXT (decl) = current_function_decl;
decl = pushdecl_outermost_localscope (decl);
- cp_finish_decl (decl, init, /*init_const_expr_p=*/false, NULL_TREE,
- LOOKUP_ONLYCONVERTING);
+ if (decl != error_mark_node)
+ add_decl_expr (decl);
}
else
{
DECL_THIS_STATIC (decl) = true;
- pushdecl_top_level_and_finish (decl, init);
+ pushdecl_top_level_and_finish (decl, NULL_TREE);
}
return decl;
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index b8b6545434b..0269fa5129a 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -16746,6 +16746,19 @@ tsubst_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl,
DECL_CONTEXT (decl) = current_function_decl;
cp_check_omp_declare_reduction (decl);
}
+ else if (VAR_P (decl)
+ && DECL_PRETTY_FUNCTION_P (decl))
+ {
+ /* For __PRETTY_FUNCTION__ we have to adjust the
+ initializer. */
+ const char *const name
+ = cxx_printable_name (current_function_decl, 2);
+ init = cp_fname_init (name, &TREE_TYPE (decl));
+ SET_DECL_VALUE_EXPR (decl, init);
+ DECL_HAS_VALUE_EXPR_P (decl) = 1;
+ DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (decl) = 1;
+ maybe_push_decl (decl);
+ }
else
{
int const_init = false;
@@ -16760,17 +16773,7 @@ tsubst_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl,
complain, in_decl, &first,
&cnt);
- if (VAR_P (decl)
- && DECL_PRETTY_FUNCTION_P (decl))
- {
- /* For __PRETTY_FUNCTION__ we have to adjust the
- initializer. */
- const char *const name
- = cxx_printable_name (current_function_decl, 2);
- init = cp_fname_init (name, &TREE_TYPE (decl));
- }
- else
- init = tsubst_init (init, decl, args, complain, in_decl);
+ init = tsubst_init (init, decl, args, complain, in_decl);
if (VAR_P (decl))
const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-__func__2.C b/gcc/testsuite/g++.dg/cpp0x/constexpr-__func__2.C
index e6782905423..673fb4f3a93 100644
--- a/gcc/testsuite/g++.dg/cpp0x/constexpr-__func__2.C
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-__func__2.C
@@ -1,5 +1,5 @@
// PR c++/70353
-// { dg-do link { target c++11 } }
+// { dg-do compile { target c++11 } }
constexpr const char* ce ()
{
@@ -8,6 +8,5 @@ constexpr const char* ce ()
const char *c = ce();
-int main()
-{
-}
+#define SA(X) static_assert((X),#X)
+SA(ce()[0] == 'c');
diff --git a/gcc/testsuite/g++.old-deja/g++.ext/pretty4.C b/gcc/testsuite/g++.old-deja/g++.ext/pretty4.C
deleted file mode 100644
index 9017d567132..00000000000
--- a/gcc/testsuite/g++.old-deja/g++.ext/pretty4.C
+++ /dev/null
@@ -1,85 +0,0 @@
-// { dg-do run }
-// Copyright (C) 2000 Free Software Foundation, Inc.
-// Contributed by Nathan Sidwell 3 Mar 2000 <nat...@codesourcery.com>
-
-// __PRETTY_FUNCTION__, __FUNCTION__ and __function__ should have the
-// type char const [X], where X is the right value for that particular function
-
-static void const *strings[4];
-static void const *tpls[4];
-static unsigned pos = 0;
-static int fail;
-static void const *ptr = 0;
-
-void unover (char const (*)[5]) {}
-void foo (char const (*)[5]) {}
-void foo (void *) {fail = 1;}
-void foo (void const *) {fail = 1;}
-void baz (char const (&)[5]) {}
-
-template<unsigned I> void PV (char const (&objRef)[I])
-{
- strings[pos] = objRef;
- tpls[pos] = __PRETTY_FUNCTION__;
- pos++;
-}
-
-void fn ()
-{
- PV (__FUNCTION__);
- PV (__func__);
- PV (__PRETTY_FUNCTION__);
- PV ("wibble");
-}
-
-void baz ()
-{
- ptr = __FUNCTION__;
- // there should be no string const merging
- if (ptr == "baz")
- fail = 1;
- // but all uses should be the same.
- if (ptr != __FUNCTION__)
- fail = 1;
-}
-int baz (int)
-{
- return ptr == __FUNCTION__;
-}
-
-int main ()
-{
- // make sure we actually emit the VAR_DECL when needed, and things have the
- // expected type.
- foo (&__FUNCTION__);
- baz (__FUNCTION__);
- unover (&__FUNCTION__);
- if (fail)
- return 1;
-
- // __FUNCTION__ should be unique across functions with the same base name
- // (it's a local static, _not_ a string).
- baz ();
- if (fail)
- return 1;
- if (baz (1))
- return 1;
- fn ();
-
- // Check the names of fn. They should all be distinct strings (though two
- // will have the same value).
- if (strings[0] == strings[1])
- return 1;
- if (strings[0] == strings[2])
- return 1;
- if (strings[1] == strings[2])
- return 1;
-
- // check the names of the template functions so invoked
- if (tpls[0] != tpls[1])
- return 1;
- if (tpls[0] == tpls[2])
- return 1;
-
- return 0;
-}
diff --git a/gcc/varasm.c b/gcc/varasm.c
index c789a03e1f3..0040f07c0e4 100644
--- a/gcc/varasm.c
+++ b/gcc/varasm.c
@@ -105,8 +105,8 @@ static int contains_pointers_p (tree);
#ifdef ASM_OUTPUT_EXTERNAL
static bool incorporeal_function_p (tree);
#endif
-static void decode_addr_const (tree, struct addr_const *);
-static hashval_t const_hash_1 (const tree);
+static bool decode_addr_const (tree, struct addr_const *, bool build = true);
+static hashval_t const_hash_1 (const tree, bool build = true);
static int compare_constant (const tree, const tree);
static void output_constant_def_contents (rtx);
static void output_addressed_constants (tree);
@@ -2877,15 +2877,17 @@ assemble_real (REAL_VALUE_TYPE d, scalar_float_mode mode, unsigned int align,
/* Given an expression EXP with a constant value,
reduce it to the sum of an assembler symbol and an integer.
Store them both in the structure *VALUE.
- EXP must be reducible. */
+ EXP must be reducible.
+ If BUILD is false the function may fail if it is address expr of a constant
+ that is not in the constant pool. */
struct addr_const {
rtx base;
poly_int64 offset;
};
-static void
-decode_addr_const (tree exp, struct addr_const *value)
+static bool
+decode_addr_const (tree exp, struct addr_const *value, bool build)
{
tree target = TREE_OPERAND (exp, 0);
poly_int64 offset = 0;
@@ -2943,7 +2945,14 @@ decode_addr_const (tree exp, struct addr_const *value)
case COMPLEX_CST:
case CONSTRUCTOR:
case INTEGER_CST:
- x = output_constant_def (target, 1);
+ if (!build)
+ {
+ x = lookup_constant_def (target);
+ if (!x)
+ return false;
+ }
+ else
+ x = output_constant_def (target, 1);
break;
case INDIRECT_REF:
@@ -2962,6 +2971,7 @@ decode_addr_const (tree exp, struct addr_const *value)
value->base = x;
value->offset = offset;
+ return true;
}
static GTY(()) hash_table<tree_descriptor_hasher> *const_desc_htab;
@@ -2985,7 +2995,7 @@ tree_descriptor_hasher::hash (constant_descriptor_tree *ptr)
}
static hashval_t
-const_hash_1 (const tree exp)
+const_hash_1 (const tree exp, bool build)
{
const char *p;
hashval_t hi;
@@ -3014,8 +3024,8 @@ const_hash_1 (const tree exp)
break;
case COMPLEX_CST:
- return (const_hash_1 (TREE_REALPART (exp)) * 5
- + const_hash_1 (TREE_IMAGPART (exp)));
+ return (const_hash_1 (TREE_REALPART (exp), build) * 5
+ + const_hash_1 (TREE_IMAGPART (exp), build));
case VECTOR_CST:
{
@@ -3023,7 +3033,7 @@ const_hash_1 (const tree exp)
hi = hi * 563 + VECTOR_CST_NELTS_PER_PATTERN (exp);
unsigned int count = vector_cst_encoded_nelts (exp);
for (unsigned int i = 0; i < count; ++i)
- hi = hi * 563 + const_hash_1 (VECTOR_CST_ENCODED_ELT (exp, i));
+ hi = hi * 563 + const_hash_1 (VECTOR_CST_ENCODED_ELT (exp, i), build);
return hi;
}
@@ -3036,7 +3046,7 @@ const_hash_1 (const tree exp)
FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (exp), idx, value)
if (value)
- hi = hi * 603 + const_hash_1 (value);
+ hi = hi * 603 + const_hash_1 (value, build);
return hi;
}
@@ -3046,7 +3056,8 @@ const_hash_1 (const tree exp)
{
struct addr_const value;
- decode_addr_const (exp, &value);
+ if (!decode_addr_const (exp, &value, build))
+ return 0;
switch (GET_CODE (value.base))
{
case SYMBOL_REF:
@@ -3072,11 +3083,11 @@ const_hash_1 (const tree exp)
case PLUS_EXPR:
case POINTER_PLUS_EXPR:
case MINUS_EXPR:
- return (const_hash_1 (TREE_OPERAND (exp, 0)) * 9
- + const_hash_1 (TREE_OPERAND (exp, 1)));
+ return (const_hash_1 (TREE_OPERAND (exp, 0), build) * 9
+ + const_hash_1 (TREE_OPERAND (exp, 1), build));
CASE_CONVERT:
- return const_hash_1 (TREE_OPERAND (exp, 0)) * 7 + 2;
+ return const_hash_1 (TREE_OPERAND (exp, 0), build) * 7 + 2;
default:
/* A language specific constant. Just hash the code. */
@@ -3549,7 +3560,7 @@ lookup_constant_def (tree exp)
struct constant_descriptor_tree key;
key.value = exp;
- key.hash = const_hash_1 (exp);
+ key.hash = const_hash_1 (exp, false);
constant_descriptor_tree *desc
= const_desc_htab->find_with_hash (&key, key.hash);
--
2.19.0
