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[PR49366] emit loc exprs for C++ non-virtual pmf template value parms
- From: Alexandre Oliva <aoliva at redhat dot com>
- To: gcc-patches at gcc dot gnu dot org
- Date: Sat, 23 Jul 2016 11:30:10 -0300
- Subject: [PR49366] emit loc exprs for C++ non-virtual pmf template value parms
- Authentication-results: sourceware.org; auth=none
We used to emit, in debug information, the values bound to pointer to
member function template parameters only when they were NULL or
virtual member functions, because those can be represented with
DW_AT_const_value.
In order to represent the symbolic pointer to member function
constants for non-virtual member functions, we'd need to be able to
emit relocations for part of DW_AT_const_value, which we don't. The
more viable alternative is to use DW_AT_location to represent such
values, as slated for inclusion in DWARFv5, according to
<URL:http://www.dwarfstd.org/ShowIssue.php?issue=130412.1>.
With this patch, when we can't emit a DW_AT_const_value, we emit each
"member" of the pointer to member function "record" as a
DW_OP_stack_value DW_OP_piece, as long as the referenced member
function is output in the same translation unit, otherwise we'd get
relocations to external symbols, something to avoid in debug sections.
Regstrapped on x86_64-linux-gnu and i686-pc-linux-gnu, and manually
cross-tested with both endiannesses (just to be sure ;-) with a
mips64-elf target. Ok to install?
for gcc/ChangeLog
PR debug/49366
* dwarf2out.c (loc_list_from_tree_1): Expand some CONSTRUCTORs
in DW_OP_pieces, just enough to handle pointers to member
functions.
(gen_remaining_tmpl_value_param_die_attribute): Use a location
expression on DWARFv5 if a constant value doesn't work.
for gcc/testsuite/ChangeLog
PR debug/49366
* g++.dg/debug/dwarf2/template-params-12.H: New.
* g++.dg/debug/dwarf2/template-params-12f.C: New.
* g++.dg/debug/dwarf2/template-params-12g.C: New.
* g++.dg/debug/dwarf2/template-params-12n.C: New.
* g++.dg/debug/dwarf2/template-params-12s.C: New.
* g++.dg/debug/dwarf2/template-params-12u.C: New.
* g++.dg/debug/dwarf2/template-params-12v.C: New.
* g++.dg/debug/dwarf2/template-params-12w.C: New.
---
gcc/dwarf2out.c | 93 +++++++++++++++++++++-
.../g++.dg/debug/dwarf2/template-params-12.H | 17 ++++
.../g++.dg/debug/dwarf2/template-params-12f.C | 7 ++
.../g++.dg/debug/dwarf2/template-params-12g.C | 7 ++
.../g++.dg/debug/dwarf2/template-params-12n.C | 10 +++
.../g++.dg/debug/dwarf2/template-params-12s.C | 8 ++
.../g++.dg/debug/dwarf2/template-params-12u.C | 7 ++
.../g++.dg/debug/dwarf2/template-params-12v.C | 6 ++
.../g++.dg/debug/dwarf2/template-params-12w.C | 6 ++
9 files changed, 160 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/g++.dg/debug/dwarf2/template-params-12.H
create mode 100644 gcc/testsuite/g++.dg/debug/dwarf2/template-params-12f.C
create mode 100644 gcc/testsuite/g++.dg/debug/dwarf2/template-params-12g.C
create mode 100644 gcc/testsuite/g++.dg/debug/dwarf2/template-params-12n.C
create mode 100644 gcc/testsuite/g++.dg/debug/dwarf2/template-params-12s.C
create mode 100644 gcc/testsuite/g++.dg/debug/dwarf2/template-params-12u.C
create mode 100644 gcc/testsuite/g++.dg/debug/dwarf2/template-params-12v.C
create mode 100644 gcc/testsuite/g++.dg/debug/dwarf2/template-params-12w.C
diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
index e3cb586..c658220 100644
--- a/gcc/dwarf2out.c
+++ b/gcc/dwarf2out.c
@@ -16142,6 +16142,89 @@ loc_list_from_tree_1 (tree loc, int want_address,
case COMPLEX_CST:
if ((ret = cst_pool_loc_descr (loc)))
have_address = 1;
+ else if (TREE_CODE (loc) == CONSTRUCTOR)
+ {
+ tree type = TREE_TYPE (loc);
+ unsigned HOST_WIDE_INT size = int_size_in_bytes (type);
+ unsigned HOST_WIDE_INT offset = 0;
+ unsigned HOST_WIDE_INT cnt;
+ constructor_elt *ce;
+
+ if (TREE_CODE (type) == RECORD_TYPE)
+ {
+ /* This is very limited, but it's enough to output
+ pointers to member functions, as long as the
+ referenced function is defined in the current
+ translation unit. */
+ FOR_EACH_VEC_SAFE_ELT (CONSTRUCTOR_ELTS (loc), cnt, ce)
+ {
+ tree val = ce->value;
+
+ tree field = ce->index;
+
+ if (val)
+ STRIP_NOPS (val);
+
+ if (!field || DECL_BIT_FIELD (field))
+ {
+ expansion_failed (loc, NULL_RTX,
+ "bitfield in record type constructor");
+ size = offset = (unsigned HOST_WIDE_INT)-1;
+ ret = NULL;
+ break;
+ }
+
+ HOST_WIDE_INT fieldsize = tree_to_shwi (DECL_SIZE_UNIT (field));
+ unsigned HOST_WIDE_INT pos = int_byte_position (field);
+ gcc_assert (pos + fieldsize <= size);
+ if (pos < offset)
+ {
+ expansion_failed (loc, NULL_RTX,
+ "out-of-order fields in record constructor");
+ size = offset = (unsigned HOST_WIDE_INT)-1;
+ ret = NULL;
+ break;
+ }
+ if (pos > offset)
+ {
+ ret1 = new_loc_descr (DW_OP_piece, pos - offset, 0);
+ add_loc_descr (&ret, ret1);
+ offset = pos;
+ }
+ if (val && fieldsize != 0)
+ {
+ ret1 = loc_descriptor_from_tree (val, want_address, context);
+ if (!ret1)
+ {
+ expansion_failed (loc, NULL_RTX,
+ "unsupported expression in field");
+ size = offset = (unsigned HOST_WIDE_INT)-1;
+ ret = NULL;
+ break;
+ }
+ add_loc_descr (&ret, ret1);
+ }
+ if (fieldsize)
+ {
+ ret1 = new_loc_descr (DW_OP_piece, fieldsize, 0);
+ add_loc_descr (&ret, ret1);
+ offset = pos + fieldsize;
+ }
+ }
+
+ if (offset != size)
+ {
+ ret1 = new_loc_descr (DW_OP_piece, size - offset, 0);
+ add_loc_descr (&ret, ret1);
+ offset = size;
+ }
+
+ have_address = !!want_address;
+ }
+ else
+ expansion_failed (loc, NULL_RTX,
+ "constructor of non-record type");
+ }
else
/* We can construct small constants here using int_loc_descriptor. */
expansion_failed (loc, NULL_RTX,
@@ -24177,7 +24260,15 @@ gen_remaining_tmpl_value_param_die_attribute (void)
FOR_EACH_VEC_ELT (*tmpl_value_parm_die_table, i, e)
{
if (!tree_add_const_value_attribute (e->die, e->arg))
- (*tmpl_value_parm_die_table)[j++] = *e;
+ {
+ dw_loc_descr_ref loc = NULL;
+ if (dwarf_version >= 5 || !dwarf_strict)
+ loc = loc_descriptor_from_tree (e->arg, 2, NULL);
+ if (loc)
+ add_AT_loc (e->die, DW_AT_location, loc);
+ else
+ (*tmpl_value_parm_die_table)[j++] = *e;
+ }
}
tmpl_value_parm_die_table->truncate (j);
}
diff --git a/gcc/testsuite/g++.dg/debug/dwarf2/template-params-12.H b/gcc/testsuite/g++.dg/debug/dwarf2/template-params-12.H
new file mode 100644
index 0000000..24c26e7
--- /dev/null
+++ b/gcc/testsuite/g++.dg/debug/dwarf2/template-params-12.H
@@ -0,0 +1,17 @@
+// Tests for the fix for PR debug/49366.
+struct B {
+ void g();
+ virtual void v() = 0;
+ virtual void w();
+};
+void B::g() {}
+void B::w() {}
+struct S : B {
+ void f();
+ void v();
+ void u();
+};
+void S::f() {}
+void S::v() {}
+template <void (B::*MF)()> void t() {}
+template <void (S::*MF)()> void t() {}
diff --git a/gcc/testsuite/g++.dg/debug/dwarf2/template-params-12f.C b/gcc/testsuite/g++.dg/debug/dwarf2/template-params-12f.C
new file mode 100644
index 0000000..e2da829
--- /dev/null
+++ b/gcc/testsuite/g++.dg/debug/dwarf2/template-params-12f.C
@@ -0,0 +1,7 @@
+// { dg-options "-gdwarf-2 -dA" }
+// { dg-final { scan-assembler-times "DIE \\(\[^\n\]*\\) DW_TAG_template_value_param" 1 } }
+// { dg-final { scan-assembler-times "DIE \\(\[^\n\]*\\) DW_TAG_template_value_param\[^\n\]*\n\[^\n\]* DW_AT_name\n\[^\n\]* DW_AT_type\n\[^\n\]*\[^\n\]* DW_AT_location\n\[^\n\]* DW_OP_addr\n\[^\n\]*_ZN1S1fEv\[^\n\]*\n\[^\n\]* DW_OP_stack_value\n\[^\n\]* DW_OP_piece\n\[^\n\]*\n\[^\n\]* DW_OP_lit0\n\[^\n\]* DW_OP_stack_value\n\[^\n\]* DW_OP_piece" 1 } }
+#include "template-params-12.H"
+/* We get a location list with a pair of DW_OP_pieces for pointers to
+ non-virtual member functions. */
+template void t<&S::f>();
diff --git a/gcc/testsuite/g++.dg/debug/dwarf2/template-params-12g.C b/gcc/testsuite/g++.dg/debug/dwarf2/template-params-12g.C
new file mode 100644
index 0000000..813f71d
--- /dev/null
+++ b/gcc/testsuite/g++.dg/debug/dwarf2/template-params-12g.C
@@ -0,0 +1,7 @@
+// { dg-options "-gdwarf-2 -dA" }
+// { dg-final { scan-assembler-times "DIE \\(\[^\n\]*\\) DW_TAG_template_value_param" 1 } }
+// { dg-final { scan-assembler-times "DIE \\(\[^\n\]*\\) DW_TAG_template_value_param\[^\n\]*\n\[^\n\]* DW_AT_name\n\[^\n\]* DW_AT_type\n\[^\n\]*\[^\n\]* DW_AT_location\n\[^\n\]* DW_OP_addr\n\[^\n\]*_ZN1B1gEv\[^\n\]*\n\[^\n\]* DW_OP_stack_value\n\[^\n\]* DW_OP_piece\n\[^\n\]*\n\[^\n\]* DW_OP_lit0\n\[^\n\]* DW_OP_stack_value\n\[^\n\]* DW_OP_piece" 1 } }
+#include "template-params-12.H"
+/* We get a location list with a pair of DW_OP_pieces for pointers to
+ non-virtual member functions. */
+template void t<&S::g>();
diff --git a/gcc/testsuite/g++.dg/debug/dwarf2/template-params-12n.C b/gcc/testsuite/g++.dg/debug/dwarf2/template-params-12n.C
new file mode 100644
index 0000000..d3c1f58
--- /dev/null
+++ b/gcc/testsuite/g++.dg/debug/dwarf2/template-params-12n.C
@@ -0,0 +1,10 @@
+// { dg-options "-gdwarf-2 -dA" }
+// { dg-final { scan-assembler-times "DIE \\(\[^\n\]*\\) DW_TAG_template_value_param" 1 } }
+// { dg-final { scan-assembler-times "DIE \\(\[^\n\]*\\) DW_TAG_template_value_param\[^\n\]*\n\[^\n\]* DW_AT_name\n\[^\n\]* DW_AT_type\n\[^\n\]* DW_AT_const_value" 1 } }
+#include "template-params-12.H"
+/* We get const_value for NULL pointers to member functions. */
+#if __cplusplus > 199711L // Ugh, C++98 barfs at both the cast and the overload.
+template void t<static_cast<void (S::*)()>(0)>();
+#else
+template void t<&S::v>();
+#endif
diff --git a/gcc/testsuite/g++.dg/debug/dwarf2/template-params-12s.C b/gcc/testsuite/g++.dg/debug/dwarf2/template-params-12s.C
new file mode 100644
index 0000000..8940eaf
--- /dev/null
+++ b/gcc/testsuite/g++.dg/debug/dwarf2/template-params-12s.C
@@ -0,0 +1,8 @@
+// { dg-options "-gdwarf-4 -gstrict-dwarf -dA" }
+// { dg-final { scan-assembler-times "DIE \\(\[^\n\]*\\) DW_TAG_template_value_param" 1 } }
+// { dg-final { scan-assembler-times "DIE \\(\[^\n\]*\\) DW_TAG_template_value_param\[^\n\]*\n\[^\n\]* DW_AT_name\n\[^\n\]* DW_AT_type\n\[^\n\]* \[^\n\]*DIE" 1 } }
+#include "template-params-12.H"
+/* We do NOT get a value or location for this one, because we've
+ enabled strict DWARF 4, and it could only be emitted as a location,
+ which is DWARF 5 only for template value params. */
+template void t<&S::f>();
diff --git a/gcc/testsuite/g++.dg/debug/dwarf2/template-params-12u.C b/gcc/testsuite/g++.dg/debug/dwarf2/template-params-12u.C
new file mode 100644
index 0000000..f79fa84
--- /dev/null
+++ b/gcc/testsuite/g++.dg/debug/dwarf2/template-params-12u.C
@@ -0,0 +1,7 @@
+// { dg-options "-gdwarf-2 -dA" }
+// { dg-final { scan-assembler-times "DIE \\(\[^\n\]*\\) DW_TAG_template_value_param" 1 } }
+// { dg-final { scan-assembler-times "DIE \\(\[^\n\]*\\) DW_TAG_template_value_param\[^\n\]*\n\[^\n\]* DW_AT_name\n\[^\n\]* DW_AT_type\n\[^\n\]* \[^\n\]*DIE" 1 } }
+#include "template-params-12.H"
+/* We do NOT get a value or location for this one, because it would
+ require a relocation to an undefined symbol in a debug section. */
+template void t<&S::u>();
diff --git a/gcc/testsuite/g++.dg/debug/dwarf2/template-params-12v.C b/gcc/testsuite/g++.dg/debug/dwarf2/template-params-12v.C
new file mode 100644
index 0000000..11aabae
--- /dev/null
+++ b/gcc/testsuite/g++.dg/debug/dwarf2/template-params-12v.C
@@ -0,0 +1,6 @@
+// { dg-options "-gdwarf-2 -dA" }
+// { dg-final { scan-assembler-times "DIE \\(\[^\n\]*\\) DW_TAG_template_value_param" 1 } }
+// { dg-final { scan-assembler-times "DIE \\(\[^\n\]*\\) DW_TAG_template_value_param\[^\n\]*\n\[^\n\]* DW_AT_name\n\[^\n\]* DW_AT_type\n\[^\n\]* DW_AT_const_value" 1 } }
+#include "template-params-12.H"
+/* We get const_value for pointers to virtual member functions. */
+template void t<&S::v>();
diff --git a/gcc/testsuite/g++.dg/debug/dwarf2/template-params-12w.C b/gcc/testsuite/g++.dg/debug/dwarf2/template-params-12w.C
new file mode 100644
index 0000000..11aabae
--- /dev/null
+++ b/gcc/testsuite/g++.dg/debug/dwarf2/template-params-12w.C
@@ -0,0 +1,6 @@
+// { dg-options "-gdwarf-2 -dA" }
+// { dg-final { scan-assembler-times "DIE \\(\[^\n\]*\\) DW_TAG_template_value_param" 1 } }
+// { dg-final { scan-assembler-times "DIE \\(\[^\n\]*\\) DW_TAG_template_value_param\[^\n\]*\n\[^\n\]* DW_AT_name\n\[^\n\]* DW_AT_type\n\[^\n\]* DW_AT_const_value" 1 } }
+#include "template-params-12.H"
+/* We get const_value for pointers to virtual member functions. */
+template void t<&S::v>();
--
2.1.0
--
Alexandre Oliva, freedom fighter http://FSFLA.org/~lxoliva/
You must be the change you wish to see in the world. -- Gandhi
Be Free! -- http://FSFLA.org/ FSF Latin America board member
Free Software Evangelist|Red Hat Brasil GNU Toolchain Engineer