{"id":810528,"url":"http://patchwork.ozlabs.org/api/patches/810528/?format=json","web_url":"http://patchwork.ozlabs.org/project/gcc/patch/20170906115238.GA129382@adacore.com/","project":{"id":17,"url":"http://patchwork.ozlabs.org/api/projects/17/?format=json","name":"GNU Compiler Collection","link_name":"gcc","list_id":"gcc-patches.gcc.gnu.org","list_email":"gcc-patches@gcc.gnu.org","web_url":null,"scm_url":null,"webscm_url":null,"list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"<20170906115238.GA129382@adacore.com>","list_archive_url":null,"date":"2017-09-06T11:52:38","name":"[Ada] Crash when issuing warning on uninitialized value","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"1e7f65c6a8913591de7f9096e6b8034c25e7fbd8","submitter":{"id":4418,"url":"http://patchwork.ozlabs.org/api/people/4418/?format=json","name":"Arnaud Charlet","email":"charlet@adacore.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/gcc/patch/20170906115238.GA129382@adacore.com/mbox/","series":[{"id":1774,"url":"http://patchwork.ozlabs.org/api/series/1774/?format=json","web_url":"http://patchwork.ozlabs.org/project/gcc/list/?series=1774","date":"2017-09-06T11:52:38","name":"[Ada] Crash when issuing warning on uninitialized value","version":1,"mbox":"http://patchwork.ozlabs.org/series/1774/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/810528/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/810528/checks/","tags":{},"related":[],"headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":["patchwork-incoming@bilbo.ozlabs.org","mailing list gcc-patches@gcc.gnu.org"],"Authentication-Results":["ozlabs.org;\n\tspf=pass (mailfrom) smtp.mailfrom=gcc.gnu.org\n\t(client-ip=209.132.180.131; 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run by ezmlm","Precedence":"bulk","List-Id":"","List-Unsubscribe":"","List-Archive":"","List-Post":"","List-Help":"","Sender":"gcc-patches-owner@gcc.gnu.org","X-Virus-Found":"No","X-Spam-SWARE-Status":"No, score=-11.9 required=5.0 tests=BAYES_00, GIT_PATCH_2,\n\tGIT_PATCH_3, RCVD_IN_DNSWL_NONE,\n\tSPF_PASS autolearn=ham version=3.3.2 spammy=","X-HELO":"rock.gnat.com","Date":"Wed, 6 Sep 2017 07:52:38 -0400","From":"Arnaud Charlet ","To":"gcc-patches@gcc.gnu.org","Cc":"Yannick Moy ","Subject":"[Ada] Crash when issuing warning on uninitialized value","Message-ID":"<20170906115238.GA129382@adacore.com>","MIME-Version":"1.0","Content-Type":"multipart/mixed; boundary=\"k1lZvvs/B4yU6o8G\"","Content-Disposition":"inline","User-Agent":"Mutt/1.5.23 (2014-03-12)"},"content":"When issuing a warning on a read of an uninitialized variable through\nreading an attribute such as Loop_Entry, GNAT could crash. Now fixed.\n\nGNAT issues a warning as expected on the following code:\n\n $ gcc -c s.adb\n\n 1. package S is\n 2.\n 3. type Array_Range is range 1 .. 10;\n 4.\n 5. type IntArray is array (Array_Range) of Integer;\n 6.\n 7. procedure Move (Dest, Src : aliased out IntArray);\n 8.\n 9. end S;\n\n 1. package body S is\n 2.\n 3. procedure Move (Dest, Src : aliased out IntArray) is\n 4. begin\n 5. for Index in Dest'Range loop\n 6. pragma Assert (for all J in Dest'First .. Index - 1 =>\n 7. Dest (J) = Src'Loop_Entry (J));\n 1 2\n >>> warning: \"Dest\" may be referenced before it has a value\n >>> warning: \"Src\" may be referenced before it has a value\n\n 8.\n 9. Dest (Index) := Src (Index);\n 10. Src (Index) := 0;\n 11. end loop;\n 12. end Move;\n 13.\n 14. end S;\n\nTested on x86_64-pc-linux-gnu, committed on trunk\n\n2017-09-06 Yannick Moy \n\n\t* sem_warn.adb (Check_References): Take into\n\taccount possibility of attribute reference as original node.","diff":"Index: sem_warn.adb\n===================================================================\n--- sem_warn.adb\t(revision 251773)\n+++ sem_warn.adb\t(working copy)\n@@ -1382,16 +1382,22 @@\n -- deal with case where original unset reference has been\n -- rewritten during expansion.\n \n- -- In some cases, the original node may be a type conversion\n- -- or qualification, and in this case we want the object\n- -- entity inside.\n+ -- In some cases, the original node may be a type\n+ -- conversion, a qualification or an attribute reference and\n+ -- in this case we want the object entity inside. Same for\n+ -- an expression with actions.\n \n UR := Original_Node (UR);\n while Nkind (UR) = N_Type_Conversion\n or else Nkind (UR) = N_Qualified_Expression\n or else Nkind (UR) = N_Expression_With_Actions\n+ or else Nkind (UR) = N_Attribute_Reference\n loop\n- UR := Expression (UR);\n+ if Nkind (UR) = N_Attribute_Reference then\n+ UR := Prefix (UR);\n+ else\n+ UR := Expression (UR);\n+ end if;\n end loop;\n \n -- Don't issue warning if appearing inside Initial_Condition\n","prefixes":["Ada"]}