From 706d088346930eeee11befa93330375164e175b9 Mon Sep 17 00:00:00 2001 From: Pedro Alves Date: Wed, 12 Feb 2014 13:30:21 +0000 Subject: [PATCH] Explicitly mark vtables as code space Ports for Hardvard architectures will typically have in their pointer_to_address hook a check for TYPE_CODE_SPACE in their "pointer_to_address" gdbarch method. E.g., rl78's: /* Is it a code address? */ if (TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_FUNC || TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_METHOD || TYPE_CODE_SPACE (TYPE_TARGET_TYPE (type)) || TYPE_LENGTH (type) == 4) return rl78_make_instruction_address (addr); else return rl78_make_data_address (addr); The avr port is similar. The vtable type is a struct type gdb itself bakes. Being neither a function, nor a method, and absent explicit flagging as residing in code space, ends up being considered data. This patch marks the type as code when it is created, on the theory that this is needed for all Hardvard architectures. I believe this should make no difference on archs with flat address space. Testing on x86-64 GNU/Linux shows no changes. gdb/ 2014-02-12 Pedro Alves Kevin Buettner * gnu-v3-abi.c (build_gdb_vtable_type): Return a type marked with TYPE_INSTANCE_FLAG_CODE_SPACE. Kevin Buettner, at , writes, re. rl78: This patch, for rl78 using the default multilib, fixes 5 failures in gdb.cp/casts.exp, 2 failures in gdb.cp/class2.exp, 115 failures in gdb.mi/mi-var-rtti.exp, and 2 failures in gdb.python/py-value.exp. It introduces 9 failures (regressions) in gdb.mi/mi-var-rtti.exp. One of the regressions is: FAIL: gdb.mi/mi-var-rtti.exp: list children of s.public in type_update_when_use_rtti The relevant lines from the log file from a pre-patch test run are as follows: -var-list-children S.public ^done,numchild="1",children=[child={name="S.public.ptr",exp="ptr",numchild="1",type="Base *",thread-id="1"}],has_more="0" (gdb) PASS: gdb.mi/mi-var-rtti.exp: list children of s.public in type_update_when_use_rtti Expecting: \^done,numchild=".*",children=\[child={name="S.public.ptr.public",exp="public",numchild="1"(,thread-id="[0-9]+")?}.*\],has_more="0" Expecting: ^(-var-list-children S\.public\.ptr [ ]+)?(\^done,numchild=".*",children=\[child={name="S.public.ptr.public",exp="public",numchild="1"(,thread-id="[0-9]+")?}.*\],has_more="0"[ ]+[(]gdb[)] [ ]*) The same set of lines for the failing (post-patch) run are instead: -var-list-children S.public &"warning: can't find linker symbol for virtual table for `Base' value\n" &"warning: found `typeinfo for __cxxabiv1::__vmi_class_type_info' instead\n" &"warning: can't find linker symbol for virtual table for `Base' value\n" &"warning: found `typeinfo for __cxxabiv1::__vmi_class_type_info' instead\n" &"warning: can't find linker symbol for virtual table for `Base' value\n" &"warning: found `typeinfo for __cxxabiv1::__vmi_class_type_info' instead\n" ^done,numchild="1",children=[child={name="S.public.ptr",exp="ptr",numchild="1",type="Base *",thread-id="1"}],has_more="0" (gdb) FAIL: gdb.mi/mi-var-rtti.exp: list children of s.public in type_update_when_use_rtti Expecting: \^done,numchild=".*",children=\[child={name="S.public.ptr.public",exp="public",numchild="1"(,thread-id="[0-9]+")?}.*\],has_more="0" Expecting: ^(-var-list-children S\.public\.ptr [ ]+)?(\^done,numchild=".*",children=\[child={name="S.public.ptr.public",exp="public",numchild="1"(,thread-id="[0-9]+")?}.*\],has_more="0"[ ]+[(]gdb[)] [ ]*) Note that the difference between these are the warnings regarding linker symbols. Aside from the warnings, the result is the same. I.e. gdb produces the correct answer despite the warnings. The reason for the other 8 failures is the same: the test harness is not expecting these warnings. I spent some time (a while ago) looking at the reason for these warnings. As I recall, we are now getting further along in the type resolution process than we were without my patch. I.e. for the example above, the code in question never got to the point where it was looking for the specified linker symbol. So it seems to me that, at worst, my patch exposes some other problem, but is not directly the cause of the problem. --- gdb/ChangeLog | 6 ++++++ gdb/gnu-v3-abi.c | 2 +- 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 5e9e9b8c6f4..41397b21e63 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,9 @@ +2014-02-12 Pedro Alves + Kevin Buettner + + * gnu-v3-abi.c (build_gdb_vtable_type): Return a type marked with + TYPE_INSTANCE_FLAG_CODE_SPACE. + 2014-02-12 Pedro Alves * h8300-tdep.c (pseudo_from_raw_register) diff --git a/gdb/gnu-v3-abi.c b/gdb/gnu-v3-abi.c index a08dc368b4f..ceccbe52886 100644 --- a/gdb/gnu-v3-abi.c +++ b/gdb/gnu-v3-abi.c @@ -171,7 +171,7 @@ build_gdb_vtable_type (struct gdbarch *arch) TYPE_TAG_NAME (t) = "gdb_gnu_v3_abi_vtable"; INIT_CPLUS_SPECIFIC (t); - return t; + return make_type_with_address_space (t, TYPE_INSTANCE_FLAG_CODE_SPACE); } -- 2.30.2