139 lines
4.2 KiB
Diff
139 lines
4.2 KiB
Diff
From 6c9e159dbd1a35aafa134fcd52982174236a8dd9 Mon Sep 17 00:00:00 2001
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From: Tom de Vries <tdevries@suse.de>
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Date: Thu, 5 Oct 2023 23:22:11 +0200
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Subject: [PATCH 3/3] [gdb/go] Handle v3 go_0 mangled prefix
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With gcc-10 we have:
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...
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(gdb) break package2.Foo^M
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Breakpoint 2 at 0x402563: file package2.go, line 5.^M
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(gdb) PASS: gdb.go/package.exp: setting breakpoint 1
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...
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but with gcc-11:
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...
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gdb) break package2.Foo^M
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Function "package2.Foo" not defined.^M
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Make breakpoint pending on future shared library load? (y or [n]) n^M
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(gdb) FAIL: gdb.go/package.exp: gdb_breakpoint: set breakpoint at package2.Foo
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...
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In the gcc-10 case, though the exec contains dwarf, it's not used to set the
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breakpoint (which is an independent problem, filed as PR go/30941), instead
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the minimal symbol information is used.
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The minimal symbol information changed between gcc-10 and gcc-11:
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...
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$ nm a.out.10 | grep Foo
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000000000040370d T go.package2.Foo
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0000000000404e50 R go.package2.Foo..f
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$ nm a.out.11 | grep Foo
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0000000000403857 T go_0package2.Foo
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0000000000405030 R go_0package2.Foo..f
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...
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A new v3 mangling scheme was used. The mangling schemes define a separator
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character and mangling character:
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- for v2, dot is used both as separator character and mangling character, and
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- for v3, dot is used as separator character and underscore as mangling
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character.
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For more details, see [1] and [2].
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In v3, "_0" demangles to ".". [ See gcc commit a01dda3c23b ("compiler, libgo:
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change mangling scheme"), function Special_char_code::Special_char_code. ]
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Handle the new go_0 prefix in unpack_mangled_go_symbol, which fixes the
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test-case.
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Note that this doesn't fix this regression:
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...
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$ gccgo-10 package2.go -c -g0
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$ gccgo-10 package1.go package2.o -g0
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$ gdb -q -batch a.out -ex "break go.package2.Foo"
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Breakpoint 1 at 0x40370d
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$ gccgo-11 package2.go -c -g0
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$ gccgo-11 package1.go package2.o -g0
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$ gdb -q -batch a.out -ex "break go.package2.Foo"
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Function "go.package2.Foo" not defined.
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...
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With gcc-10, we set a breakpoint on the mangled minimal symbol. That
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one has simply changed for gcc-11, so it's equivalent to using:
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...
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$ gdb -q -batch a.out -ex "break go_0package2.Foo"
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Breakpoint 1 at 0x403857
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...
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which does work.
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Tested on x86_64-linux:
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- openSUSE Leap 15.4, using gccgo-7,
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- openSUSE Tumbleweed, using gccgo-13.
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PR go/27238
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Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=27238
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[1] https://go-review.googlesource.com/c/gofrontend/+/271726
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[2] https://github.com/golang/go/issues/41862#issuecomment-707244103
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---
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gdb/go-lang.c | 30 +++++++++++++++++++++++++++---
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1 file changed, 27 insertions(+), 3 deletions(-)
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diff --git a/gdb/go-lang.c b/gdb/go-lang.c
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index f9176ace71d..8a5568f56e0 100644
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--- a/gdb/go-lang.c
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+++ b/gdb/go-lang.c
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@@ -233,16 +233,28 @@ unpack_mangled_go_symbol (const char *mangled_name,
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libgo_.*: used by gccgo's runtime
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Thus we don't support -fgo-prefix (except as used by the runtime). */
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- if (!startswith (mangled_name, "go.")
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- && !startswith (mangled_name, "libgo_"))
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+ bool v3;
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+ if (startswith (mangled_name, "go_0"))
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+ /* V3 mangling detected, see
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+ https://go-review.googlesource.com/c/gofrontend/+/271726 . */
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+ v3 = true;
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+ else if (startswith (mangled_name, "go.")
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+ || startswith (mangled_name, "libgo_"))
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+ v3 = false;
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+ else
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return NULL;
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/* Quick check for whether a search may be fruitful. */
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/* Ignore anything with @plt, etc. in it. */
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if (strchr (mangled_name, '@') != NULL)
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return NULL;
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+
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/* It must have at least two dots. */
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- first_dot = strchr (mangled_name, '.');
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+ if (v3)
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+ first_dot = strchr (mangled_name, '0');
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+ else
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+ first_dot = strchr (mangled_name, '.');
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+
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if (first_dot == NULL)
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return NULL;
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/* Treat "foo.bar" as unmangled. It can collide with lots of other
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@@ -263,6 +275,18 @@ unpack_mangled_go_symbol (const char *mangled_name,
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gdb::unique_xmalloc_ptr<char> result = make_unique_xstrdup (mangled_name);
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buf = result.get ();
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+ if (v3)
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+ {
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+ /* Replace "go_0" with "\0go.". */
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+ buf[0] = '\0';
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+ buf[1] = 'g';
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+ buf[2] = 'o';
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+ buf[3] = '.';
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+
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+ /* Skip the '\0'. */
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+ buf++;
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+ }
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+
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/* Search backwards looking for "N<digit(s)>". */
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p = buf + len;
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saw_digit = method_type = NULL;
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--
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2.35.3
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