From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from barracuda.ebox.ca (barracuda.ebox.ca [96.127.255.19]) by sourceware.org (Postfix) with ESMTPS id 62F553954C18 for ; Tue, 12 May 2020 21:17:51 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 62F553954C18 X-ASG-Debug-ID: 1589318270-0c856e18f31444ef0001-fS2M51 Received: from smtp.ebox.ca (smtp.ebox.ca [96.127.255.82]) by barracuda.ebox.ca with ESMTP id woLzjEnlxv8YgTwN (version=TLSv1 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Tue, 12 May 2020 17:17:50 -0400 (EDT) X-Barracuda-Envelope-From: simon.marchi@efficios.com X-Barracuda-RBL-Trusted-Forwarder: 96.127.255.82 Received: from epycamd.internal.efficios.com (192-222-181-218.qc.cable.ebox.net [192.222.181.218]) by smtp.ebox.ca (Postfix) with ESMTP id 8D541441B21; Tue, 12 May 2020 17:17:50 -0400 (EDT) From: Simon Marchi X-Barracuda-Effective-Source-IP: 192-222-181-218.qc.cable.ebox.net[192.222.181.218] X-Barracuda-Apparent-Source-IP: 192.222.181.218 X-Barracuda-RBL-IP: 192.222.181.218 To: gdb-patches@sourceware.org Subject: [PATCH v2 38/42] Add comp_unit_head to dwarf2_per_cu_data Date: Tue, 12 May 2020 17:17:08 -0400 X-ASG-Orig-Subj: [PATCH v2 38/42] Add comp_unit_head to dwarf2_per_cu_data Message-Id: <20200512211712.6543-39-simon.marchi@efficios.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200512210913.5593-1-simon.marchi@efficios.com> References: <20200512210913.5593-1-simon.marchi@efficios.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Barracuda-Connect: smtp.ebox.ca[96.127.255.82] X-Barracuda-Start-Time: 1589318270 X-Barracuda-Encrypted: DHE-RSA-AES256-SHA X-Barracuda-URL: https://96.127.255.19:443/cgi-mod/mark.cgi X-Barracuda-Scan-Msg-Size: 6180 X-Virus-Scanned: by bsmtpd at ebox.ca X-Barracuda-BRTS-Status: 1 X-Barracuda-Spam-Score: 0.00 X-Barracuda-Spam-Status: No, SCORE=0.00 using global scores of TAG_LEVEL=1000.0 QUARANTINE_LEVEL=1000.0 KILL_LEVEL=8.0 tests= X-Barracuda-Spam-Report: Code version 3.2, rules version 3.2.3.81805 Rule breakdown below pts rule name description ---- ---------------------- -------------------------------------------------- X-Spam-Status: No, score=-25.0 required=5.0 tests=BAYES_00, GIT_PATCH_0, KAM_DMARC_NONE, KAM_DMARC_STATUS, RCVD_IN_DNSWL_LOW, SPF_HELO_NONE, SPF_SOFTFAIL, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: gdb-patches@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gdb-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 12 May 2020 21:17:52 -0000 From: Simon Marchi The per_cu_header_read_in function allows obtaining a filled comp_unit_head object for a given dwarf2_per_cu_data object. If a dwarf2_cu object exists for this dwarf2_per_cu_data, then it just returns a pointer to the comp_unit_head from that dwarf2_cu. Otherwise, it reads the header into a temporary buffer provided by the caller, and returns a pointer to that. Since the dwarf2_per_cu_data::cu link is going to be removed (dwarf2_per_cu_data will become objfile-independent while dwarf2_cu stays objfile-dependent), we cannot rely anymore on returning the header from the dwarf2_cu object. The not too complex solution implemented by this patch is to keep a copy of the header in the dwarf2_per_cu_data object, independent from the copy in dwarf2_cu. The new copy is only used in the addr_size, offset_size and ref_addr_size methods of dwarf2_per_cu_data. There's nothing intrinsic to the comp_unit_head object that prevents it to be shared between two dwarf2_cu objects (belonging to different objfiles) representing the same CU. In other words, I think we could eventually get rid of the copy in dwarf2_cu to only keep the one in dwarf2_per_cu_data. It is not trivial, however, so I have decided not to do it for the moment. gdb/ChangeLog: * dwarf2/read.h (struct dwarf2_per_cu_data) : New fields. : New method. * dwarf2/read.c (per_cu_header_read_in): Remove. (dwarf2_per_cu_data::get_header): New. (dwarf2_per_cu_data::addr_size): Update. (dwarf2_per_cu_data::offset_size): Update. (dwarf2_per_cu_data::ref_addr_size): Update. --- gdb/dwarf2/read.c | 52 ++++++++++++++++------------------------------- gdb/dwarf2/read.h | 19 +++++++++++++++++ 2 files changed, 37 insertions(+), 34 deletions(-) diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c index ad4eae3fe60..dc72b6320a8 100644 --- a/gdb/dwarf2/read.c +++ b/gdb/dwarf2/read.c @@ -23295,26 +23295,23 @@ dwarf2_symbol_mark_computed (const struct attribute *attr, struct symbol *sym, } } -/* Return comp_unit_head for PER_CU, either already available in PER_CU->CU - (CU_HEADERP is unused in such case) or prepare a temporary copy at - CU_HEADERP first. */ +/* See read.h. */ -static const struct comp_unit_head * -per_cu_header_read_in (struct comp_unit_head *cu_headerp, - const struct dwarf2_per_cu_data *per_cu) +const comp_unit_head * +dwarf2_per_cu_data::get_header () const { - const gdb_byte *info_ptr; - - if (per_cu->cu) - return &per_cu->cu->header; + if (!m_header_read_in) + { + const gdb_byte *info_ptr + = this->section->buffer + to_underlying (this->sect_off); - info_ptr = per_cu->section->buffer + to_underlying (per_cu->sect_off); + memset (&m_header, 0, sizeof (m_header)); - memset (cu_headerp, 0, sizeof (*cu_headerp)); - read_comp_unit_head (cu_headerp, info_ptr, per_cu->section, - rcuh_kind::COMPILE); + read_comp_unit_head (&m_header, info_ptr, this->section, + rcuh_kind::COMPILE); + } - return cu_headerp; + return &m_header; } /* See read.h. */ @@ -23322,12 +23319,7 @@ per_cu_header_read_in (struct comp_unit_head *cu_headerp, int dwarf2_per_cu_data::addr_size () const { - struct comp_unit_head cu_header_local; - const struct comp_unit_head *cu_headerp; - - cu_headerp = per_cu_header_read_in (&cu_header_local, this); - - return cu_headerp->addr_size; + return this->get_header ()->addr_size; } /* See read.h. */ @@ -23335,12 +23327,7 @@ dwarf2_per_cu_data::addr_size () const int dwarf2_per_cu_data::offset_size () const { - struct comp_unit_head cu_header_local; - const struct comp_unit_head *cu_headerp; - - cu_headerp = per_cu_header_read_in (&cu_header_local, this); - - return cu_headerp->offset_size; + return this->get_header ()->offset_size; } /* See read.h. */ @@ -23348,15 +23335,12 @@ dwarf2_per_cu_data::offset_size () const int dwarf2_per_cu_data::ref_addr_size () const { - struct comp_unit_head cu_header_local; - const struct comp_unit_head *cu_headerp; - - cu_headerp = per_cu_header_read_in (&cu_header_local, this); + const comp_unit_head *header = this->get_header (); - if (cu_headerp->version == 2) - return cu_headerp->addr_size; + if (header->version == 2) + return header->addr_size; else - return cu_headerp->offset_size; + return header->offset_size; } /* See read.h. */ diff --git a/gdb/dwarf2/read.h b/gdb/dwarf2/read.h index 3500b0e7ba9..b75be312217 100644 --- a/gdb/dwarf2/read.h +++ b/gdb/dwarf2/read.h @@ -22,6 +22,7 @@ #include #include +#include "dwarf2/comp-unit.h" #include "dwarf2/index-cache.h" #include "dwarf2/section.h" #include "filename-seen-cache.h" @@ -468,6 +469,21 @@ struct dwarf2_per_cu_data /* Backlink to the owner of this. */ dwarf2_per_bfd *per_bfd; + /* DWARF header of this CU. Note that dwarf2_cu reads its own version of the + header, which may differ from this one, since it may pass rcuh_kind::TYPE + to read_comp_unit_head, whereas for dwarf2_per_cu_data we always pass + rcuh_kind::COMPILE. + + Don't access this field directly, use the get_header method instead. It + should be private, but we can't make it private at the moment. */ + mutable comp_unit_head m_header; + + /* True if HEADER has been read in. + + Don't access this field directly. It should be private, but we can't make + it private at the moment. */ + mutable bool m_header_read_in; + /* When dwarf2_per_bfd::using_index is true, the 'quick' field is active. Otherwise, the 'psymtab' field is active. */ union @@ -537,6 +553,9 @@ struct dwarf2_per_cu_data imported_symtabs = nullptr; } + /* Get the header of this per_cu, reading it if necessary. */ + const comp_unit_head *get_header () const; + /* Return the address size given in the compilation unit header for this CU. */ int addr_size () const; -- 2.26.2