From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by sourceware.org (Postfix) with ESMTPS id 8340E3858426 for ; Sat, 18 Mar 2023 16:51:05 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 8340E3858426 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1679158265; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=0Gr3VPQ8Am9Pw+NxgTD+TiIt3Zn+CZgUD+6XGBylPhM=; b=e0B/Xx6yIKdCG66l4lVLfaH6sOVo643PcuhDI/fv5uNxu9JLSLf2S/AdaYWM0oiPM8ycYl QejyHtyuD89w51dVYF+XxlMp1PYN3bVl54h5oZqVoUOfAC9yGV/YSRt4ywB+wyj4YEhauy OOBgoLWCmp47NGrnWkvuSu0r+2ZWZy0= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-177-asw88AYmPUCgeHPAauKg4A-1; Sat, 18 Mar 2023 12:51:03 -0400 X-MC-Unique: asw88AYmPUCgeHPAauKg4A-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 5DDC4800B23 for ; Sat, 18 Mar 2023 16:51:03 +0000 (UTC) Received: from t14s.localdomain.com (unknown [10.2.17.70]) by smtp.corp.redhat.com (Postfix) with ESMTP id 350186B590; Sat, 18 Mar 2023 16:51:03 +0000 (UTC) From: David Malcolm To: gcc-patches@gcc.gnu.org Cc: David Malcolm Subject: [pushed] analyzer: fix ICE on certain longjmp calls [PR109094] Date: Sat, 18 Mar 2023 12:51:01 -0400 Message-Id: <20230318165101.3685516-1-dmalcolm@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="US-ASCII"; x-default=true X-Spam-Status: No, score=-11.5 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,GIT_PATCH_0,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_NONE,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: PR analyzer/109094 reports an ICE in the analyzer seen on qemu's target/i386/tcg/translate.c The issue turned out to be that when handling a longjmp, the code to pop the frames was generating an svalue for the result_decl of any popped frame that had a non-void return type (and discarding it) leading to "uninit" poisoned_svalue_diagnostic instances being saved since the result_decl is only set by the greturn stmt. Later, when checking the feasibility of the path to these diagnostics, m_check_expr was evaluated in the context of the frame of the longjmp, leading to an attempt to evaluate the result_decl of each intervening frames whilst in the context of the topmost frame, leading to an assertion failure in frame_region::get_region_for_local here: 919 case RESULT_DECL: 920 gcc_assert (DECL_CONTEXT (expr) == m_fun->decl); 921 break; This patch updates the analyzer's longjmp implementation so that it doesn't attempt to generate svalues for the result_decls when popping frames, fixing the assertion failure (and presumably fixing "uninit" false positives in a release build). Successfully bootstrapped & regrtested on x86_64-pc-linux-gnu. Analyzer integration tests shows no regressions. Pushed to trunk as r13-6749-g430d7d88c1a123. gcc/analyzer/ChangeLog: PR analyzer/109094 * region-model.cc (region_model::on_longjmp): Pass false for new "eval_return_svalue" param of pop_frame. (region_model::pop_frame): Add new "eval_return_svalue" param and use it to suppress the call to get_rvalue on the result when needed by on_longjmp. * region-model.h (region_model::pop_frame): Add new "eval_return_svalue" param. gcc/testsuite/ChangeLog: PR analyzer/109094 * gcc.dg/analyzer/setjmp-pr109094.c: New test. Signed-off-by: David Malcolm --- gcc/analyzer/region-model.cc | 15 ++++++-- gcc/analyzer/region-model.h | 3 +- .../gcc.dg/analyzer/setjmp-pr109094.c | 38 +++++++++++++++++++ 3 files changed, 52 insertions(+), 4 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/analyzer/setjmp-pr109094.c diff --git a/gcc/analyzer/region-model.cc b/gcc/analyzer/region-model.cc index 56beaa82f95..fb81d43f91b 100644 --- a/gcc/analyzer/region-model.cc +++ b/gcc/analyzer/region-model.cc @@ -1952,7 +1952,7 @@ region_model::on_longjmp (const gcall *longjmp_call, const gcall *setjmp_call, setjmp was called. */ gcc_assert (get_stack_depth () >= setjmp_stack_depth); while (get_stack_depth () > setjmp_stack_depth) - pop_frame (NULL, NULL, ctxt); + pop_frame (NULL, NULL, ctxt, false); gcc_assert (get_stack_depth () == setjmp_stack_depth); @@ -4679,6 +4679,10 @@ region_model::get_current_function () const If OUT_RESULT is non-null, copy any return value from the frame into *OUT_RESULT. + If EVAL_RETURN_SVALUE is false, then don't evaluate the return value. + This is for use when unwinding frames e.g. due to longjmp, to suppress + erroneously reporting uninitialized return values. + Purge the frame region and all its descendent regions. Convert any pointers that point into such regions into POISON_KIND_POPPED_STACK svalues. */ @@ -4686,7 +4690,8 @@ region_model::get_current_function () const void region_model::pop_frame (tree result_lvalue, const svalue **out_result, - region_model_context *ctxt) + region_model_context *ctxt, + bool eval_return_svalue) { gcc_assert (m_current_frame); @@ -4700,7 +4705,9 @@ region_model::pop_frame (tree result_lvalue, tree fndecl = m_current_frame->get_function ()->decl; tree result = DECL_RESULT (fndecl); const svalue *retval = NULL; - if (result && TREE_TYPE (result) != void_type_node) + if (result + && TREE_TYPE (result) != void_type_node + && eval_return_svalue) { retval = get_rvalue (result, ctxt); if (out_result) @@ -4712,6 +4719,8 @@ region_model::pop_frame (tree result_lvalue, if (result_lvalue && retval) { + gcc_assert (eval_return_svalue); + /* Compute result_dst_reg using RESULT_LVALUE *after* popping the frame, but before poisoning pointers into the old frame. */ const region *result_dst_reg = get_lvalue (result_lvalue, ctxt); diff --git a/gcc/analyzer/region-model.h b/gcc/analyzer/region-model.h index 197b5358678..fe3db0b0c98 100644 --- a/gcc/analyzer/region-model.h +++ b/gcc/analyzer/region-model.h @@ -341,7 +341,8 @@ class region_model function * get_current_function () const; void pop_frame (tree result_lvalue, const svalue **out_result, - region_model_context *ctxt); + region_model_context *ctxt, + bool eval_return_svalue = true); int get_stack_depth () const; const frame_region *get_frame_at_index (int index) const; diff --git a/gcc/testsuite/gcc.dg/analyzer/setjmp-pr109094.c b/gcc/testsuite/gcc.dg/analyzer/setjmp-pr109094.c new file mode 100644 index 00000000000..10591ce60a7 --- /dev/null +++ b/gcc/testsuite/gcc.dg/analyzer/setjmp-pr109094.c @@ -0,0 +1,38 @@ +/* Reduced from an ICE seen in qemu's target/i386/tcg/translate.c */ + +typedef long int __jmp_buf[8]; +struct __jmp_buf_tag { + __jmp_buf __jmpbuf; +}; +typedef struct __jmp_buf_tag sigjmp_buf[1]; + +extern int __sigsetjmp(sigjmp_buf env, int savesigs); +extern void siglongjmp(sigjmp_buf env, int val); + +typedef struct DisasContextBase { + int num_insns; +} DisasContextBase; + +typedef struct DisasContext { + DisasContextBase base; + sigjmp_buf jmpbuf; +} DisasContext; + +extern int translator_ldub(DisasContextBase *base, int); + +int advance_pc(DisasContext *s, int num_bytes) { + if (s->base.num_insns > 1) { + siglongjmp(s->jmpbuf, 2); + } + return 0; +} + +static inline int x86_ldub_code(DisasContext *s) { + return translator_ldub(&s->base, advance_pc(s, 1)); +} + +static void disas_insn(DisasContext *s) { + int b; + __sigsetjmp(s->jmpbuf, 0); + b = x86_ldub_code(s); +} -- 2.26.3