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From: "funanzeng at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/106338] New: RISC-V static-chain register may be clobbered by PLT stubs
Date: Mon, 18 Jul 2022 08:00:40 +0000	[thread overview]
Message-ID: <bug-106338-4@http.gcc.gnu.org/bugzilla/> (raw)

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106338

            Bug ID: 106338
           Summary: RISC-V static-chain register may be clobbered by PLT
                    stubs
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: funanzeng at gmail dot com
  Target Milestone: ---

In commit 09cae7507d9e88f2b05cf3a9404bf181e65ccbac, Palmer ported GCC to RISC-V
and t2 were chosen as the static chain register. However, when I supporting
this feature in LLVM(https://reviews.llvm.org/D129106), jrtc27 pointed out that
this issue.

In practice, static chain parameters are only used in Go and is always used
with closures, where the function pointer is already resolved. As a result,
this issue may not be triggered unless a user directly calls a foreign function
with a static chain parameter, and thus has not caused any problem.

FYI, in a recent change to the RISC-V ABI, STO_RISCV_VARIANT_CC was added to
support unknown ABI.

             reply	other threads:[~2022-07-18  8:00 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-18  8:00 funanzeng at gmail dot com [this message]
2022-07-18  8:12 ` [Bug target/106338] " pinskia at gcc dot gnu.org
2022-07-18  8:13 ` pinskia at gcc dot gnu.org
2022-07-18  8:17 ` schwab@linux-m68k.org
2022-08-09 19:47 ` pinskia at gcc dot gnu.org
2022-08-09 21:11 ` andrew at sifive dot com
2022-08-10  2:58 ` kito at gcc dot gnu.org

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