From b0b8879e292218bfb27584515e98a46379c9c666 Mon Sep 17 00:00:00 2001 From: Simon Marchi Date: Mon, 4 Oct 2021 18:16:40 +0200 Subject: [PATCH] [gdb/symtab] Use unrelocated addresses in call_site Consider test-case gdb.trace/entry-values.exp with target board unix/-fPIE/-pie. Using this command we have an abbreviated version, and can see the correct @entry values for foo: ... $ gdb -q -batch outputs/gdb.trace/entry-values/entry-values \ -ex start \ -ex "break foo" \ -ex "set print entry-values both" \ -ex continue Temporary breakpoint 1 at 0x679 Temporary breakpoint 1, 0x0000555555554679 in main () Breakpoint 2 at 0x55555555463e Breakpoint 2, 0x000055555555463e in foo (i=0, i@entry=2, j=2, j@entry=3) ... Now, let's try the same again, but run directly to foo rather than stopping at main: ... $ gdb -q -batch outputs/gdb.trace/entry-values/entry-values \ -ex "break foo" \ -ex "set print entry-values both" \ -ex run Breakpoint 1 at 0x63e Breakpoint 1, 0x000055555555463e in foo (i=0, i@entry=, \ j=2, j@entry=) ... So, what explains the difference? Noteworthy, this is a dwarf assembly test-case, with debug info for foo and bar, but not for main. In the first case: - we run to main - this does not trigger expanding debug info, because there's none for main - we set a breakpoint at foo - this triggers expanding debug info. Relocated addresses are used in call_site info (because the exec is started) - we continue to foo, and manage to find the call_site info In the second case: - we set a breakpoint at foo - this triggers expanding debug info. Unrelocated addresses are used in call_site info (because the exec is not started) - we run to foo - this triggers objfile_relocate1, but it doesn't update the call_site info addresses - we don't manage to find the call_site info We could fix this by adding the missing call_site relocation in objfile_relocate1. This solution however is counter-trend in the sense that we're trying to work towards the situation where when starting two instances of an executable, we need only one instance of debug information, implying the use of unrelocated addresses. So, fix this instead by using unrelocated addresses in call_site info. Tested on x86_64-linux. This fixes all remaining unix/-fno-PIE/-no-pie vs unix/-fPIE/-pie regressions, like f.i. PR24892. Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=24892 Co-Authored-By: Tom de Vries --- gdb/dwarf2/loc.c | 9 ++++++++- gdb/dwarf2/read.c | 4 +++- gdb/gdbtypes.c | 5 ++++- gdb/gdbtypes.h | 10 +++++----- gdb/symtab.c | 6 +++++- 5 files changed, 25 insertions(+), 9 deletions(-) diff --git a/gdb/dwarf2/loc.c b/gdb/dwarf2/loc.c index 27a1c97682a..16e0be73d02 100644 --- a/gdb/dwarf2/loc.c +++ b/gdb/dwarf2/loc.c @@ -713,7 +713,14 @@ call_site_to_target_addr (struct gdbarch *call_site_gdbarch, } case FIELD_LOC_KIND_PHYSADDR: - return FIELD_STATIC_PHYSADDR (call_site->target); + { + dwarf2_per_objfile *per_objfile = call_site->per_objfile; + compunit_symtab *cust = per_objfile->get_symtab (call_site->per_cu); + int sect_idx = COMPUNIT_BLOCK_LINE_SECTION (cust); + CORE_ADDR delta = per_objfile->objfile->section_offsets[sect_idx]; + + return FIELD_STATIC_PHYSADDR (call_site->target) + delta; + } default: internal_error (__FILE__, __LINE__, _("invalid call site target kind")); diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c index 230eb6a04b1..e036b2eac63 100644 --- a/gdb/dwarf2/read.c +++ b/gdb/dwarf2/read.c @@ -13363,6 +13363,7 @@ read_call_site_scope (struct die_info *die, struct dwarf2_cu *cu) } pc = attr->as_address () + baseaddr; pc = gdbarch_adjust_dwarf2_addr (gdbarch, pc); + pc -= baseaddr; if (cu->call_site_htab == NULL) cu->call_site_htab = htab_create_alloc_ex (16, call_site::hash, @@ -13519,7 +13520,8 @@ read_call_site_scope (struct die_info *die, struct dwarf2_cu *cu) sect_offset_str (die->sect_off), objfile_name (objfile)); else { - lowpc = gdbarch_adjust_dwarf2_addr (gdbarch, lowpc + baseaddr); + lowpc = (gdbarch_adjust_dwarf2_addr (gdbarch, lowpc + baseaddr) + - baseaddr); SET_FIELD_PHYSADDR (call_site->target, lowpc); } } diff --git a/gdb/gdbtypes.c b/gdb/gdbtypes.c index 8954c370b7b..853532838a2 100644 --- a/gdb/gdbtypes.c +++ b/gdb/gdbtypes.c @@ -6314,7 +6314,10 @@ objfile_type (struct objfile *objfile) CORE_ADDR call_site::pc () const { - return m_pc; + compunit_symtab *cust = this->per_objfile->get_symtab (this->per_cu); + CORE_ADDR delta + = this->per_objfile->objfile->section_offsets[COMPUNIT_BLOCK_LINE_SECTION (cust)]; + return m_unrelocated_pc + delta; } void _initialize_gdbtypes (); diff --git a/gdb/gdbtypes.h b/gdb/gdbtypes.h index 5fe10cb7f1e..4e5b2f1a92f 100644 --- a/gdb/gdbtypes.h +++ b/gdb/gdbtypes.h @@ -1795,19 +1795,19 @@ struct call_site { call_site (CORE_ADDR pc, dwarf2_per_cu_data *per_cu, dwarf2_per_objfile *per_objfile) - : per_cu (per_cu), per_objfile (per_objfile), m_pc (pc) + : per_cu (per_cu), per_objfile (per_objfile), m_unrelocated_pc (pc) {} static int eq (const call_site *a, const call_site *b) { - return core_addr_eq (&a->m_pc, &b->m_pc); + return core_addr_eq (&a->m_unrelocated_pc, &b->m_unrelocated_pc); } static hashval_t hash (const call_site *a) { - return core_addr_hash (&a->m_pc); + return core_addr_hash (&a->m_unrelocated_pc); } static int @@ -1849,8 +1849,8 @@ struct call_site dwarf2_per_objfile *const per_objfile = nullptr; private: - /* Address of the first instruction after this call. */ - const CORE_ADDR m_pc; + /* Unrelocated address of the first instruction after this call. */ + const CORE_ADDR m_unrelocated_pc; public: /* * Describe DW_TAG_call_site's DW_TAG_formal_parameter. */ diff --git a/gdb/symtab.c b/gdb/symtab.c index cb583846efa..85e6b084551 100644 --- a/gdb/symtab.c +++ b/gdb/symtab.c @@ -337,7 +337,11 @@ compunit_symtab::find_call_site (CORE_ADDR pc) const if (m_call_site_htab == nullptr) return nullptr; - struct call_site call_site_local (pc, nullptr, nullptr); + CORE_ADDR delta + = this->objfile->section_offsets[COMPUNIT_BLOCK_LINE_SECTION (this)]; + CORE_ADDR unrelocated_pc = pc - delta; + + struct call_site call_site_local (unrelocated_pc, nullptr, nullptr); void **slot = htab_find_slot (m_call_site_htab, &call_site_local, NO_INSERT); if (slot == nullptr) -- 2.30.2