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From: "wcohen at redhat dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug debug/103241] Odd 0 length entries in location lists
Date: Tue, 16 Nov 2021 16:18:44 +0000	[thread overview]
Message-ID: <bug-103241-4-dwrIRw335q@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-103241-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103241

--- Comment #7 from Will Cohen <wcohen at redhat dot com> ---
Looking at the set_mem.s the second issue of the 0-length location entry for
static_protections is coming from this bit of assembly in the set_memory.s:


        .byte   0x4
        .uleb128 .LVL637-.LVL615
        .uleb128 .LHOTE19-.LVL615
        .uleb128 0x3
        .byte   0x53
        .byte   0x93
        .uleb128 0x8

The attached .s and .i files were from a local compile of linux git repo commit
8ab774587903771821b59471cc723bba6d893942.  The part of the llvm-dwarf dump
related should be looking for is [0x0000000000001b1b, 0x0000000000001b1b).

llvm-dwarfdump -c --name="static_protections" arch/x86/mm/pat/set_memory.o
|more


0x00019218: DW_TAG_subprogram
              DW_AT_abstract_origin     (0x00014236 "static_protections")
              DW_AT_ranges      (0x00000bc0
                 [0x0000000000001990, 0x0000000000001b1b)
                 [0x0000000000000000, 0x00000000000000bd))
              DW_AT_frame_base  (DW_OP_call_frame_cfa)
              DW_AT_call_all_calls      (true)
              DW_AT_sibling     (0x00019807)

0x00019228:   DW_TAG_formal_parameter
                DW_AT_abstract_origin   (0x00014248 "prot")
                DW_AT_location  (0x00006f38: 
                   [0x0000000000001990, 0x0000000000001990): DW_OP_reg5 RDI
                   [0x0000000000001990, 0x00000000000019b9): DW_OP_reg5 RDI,
DW_
OP_piece 0x8
                   [0x00000000000019f0, 0x0000000000001a43): DW_OP_reg5 RDI
                   [0x0000000000001a67, 0x0000000000001aab): DW_OP_reg3 RBX
                   [0x0000000000001ace, 0x0000000000001adc): DW_OP_reg5 RDI
                   [0x0000000000001adc, 0x0000000000001af1): DW_OP_reg3 RBX,
DW_
OP_piece 0x8
                   [0x0000000000001af1, 0x0000000000001af1): DW_OP_reg3 RBX,
DW_
OP_piece 0x8
                   [0x0000000000001af1, 0x0000000000001b1b): DW_OP_reg3 RBX
                   [0x0000000000001b1b, 0x0000000000001b1b): DW_OP_reg3 RBX,
DW_
OP_piece 0x8
                   [0x0000000000000000, 0x000000000000002d): DW_OP_reg3 RBX,
DW_
OP_piece 0x8
                   [0x000000000000004e, 0x000000000000007e): DW_OP_reg3 RBX
                   [0x000000000000007e, 0x00000000000000bd): DW_OP_reg3 RBX,
DW_
OP_piece 0x8)
                DW_AT_unknown_2137      (0x00006f20)

0x00019235:   DW_TAG_formal_parameter
                DW_AT_abstract_origin   (0x00014255 "start")
                DW_AT_location  (0x00006fb1: 
                   [0x0000000000001990, 0x00000000000019f0): DW_OP_reg4 RSI
                   [0x00000000000019f0, 0x0000000000001aab): DW_OP_reg12 R12
                   [0x0000000000001aab, 0x0000000000001aba):
DW_OP_entry_value(D
W_OP_reg4 RSI), DW_OP_stack_value
                   [0x0000000000001aba, 0x0000000000001adc): DW_OP_reg4 RSI
                   [0x0000000000001adc, 0x0000000000001b1b): DW_OP_reg12 R12
                   [0x0000000000001b1b, 0x0000000000001b1b): DW_OP_reg4 RSI
                   [0x0000000000000000, 0x0000000000000025): DW_OP_reg4 RSI
                   [0x0000000000000025, 0x00000000000000bd): DW_OP_reg12 R12)
                DW_AT_unknown_2137      (0x00006fa1)

0x00019242:   DW_TAG_formal_parameter
                DW_AT_abstract_origin   (0x00014262 "pfn")
                DW_AT_location  (0x00007009: 
                   [0x0000000000001990, 0x00000000000019f0): DW_OP_reg1 RDX
                   [0x00000000000019f0, 0x0000000000001aab): DW_OP_reg15 R15
                   [0x0000000000001aab, 0x0000000000001aba):
DW_OP_entry_value(D
W_OP_reg1 RDX), DW_OP_stack_value
                   [0x0000000000001aba, 0x0000000000001adc): DW_OP_reg1 RDX
                   [0x0000000000001adc, 0x0000000000001b1b): DW_OP_reg15 R15
                   [0x0000000000001b1b, 0x0000000000001b1b): DW_OP_reg1 RDX
                   [0x0000000000000000, 0x000000000000001c): DW_OP_reg1 RDX
                   [0x000000000000001c, 0x00000000000000bd): DW_OP_reg15 R15)
                DW_AT_unknown_2137      (0x00006ff9)

0x0001924f:   DW_TAG_formal_parameter
                DW_AT_abstract_origin   (0x0001426f "npg")
                DW_AT_location  (0x00007061: 
                   [0x0000000000001990, 0x00000000000019f0): DW_OP_reg2 RCX
                   [0x00000000000019f0, 0x0000000000001aab): DW_OP_reg13 R13
                   [0x0000000000001aab, 0x0000000000001aba):
DW_OP_entry_value(D
W_OP_reg2 RCX), DW_OP_stack_value
                   [0x0000000000001aba, 0x0000000000001adc): DW_OP_reg2 RCX
                   [0x0000000000001adc, 0x0000000000001b1b): DW_OP_reg13 R13
                   [0x0000000000001b1b, 0x0000000000001b1b): DW_OP_reg2 RCX
                   [0x0000000000000000, 0x0000000000000010): DW_OP_reg2 RCX
                   [0x0000000000000010, 0x00000000000000bd): DW_OP_reg13 R13)
                DW_AT_unknown_2137      (0x00007051)

0x0001925c:   DW_TAG_formal_parameter
                DW_AT_abstract_origin   (0x0001427c "lpsize")
                DW_AT_location  (0x000070b3: 
                   [0x0000000000001990, 0x00000000000019d5): DW_OP_reg8 R8
                   [0x00000000000019d5, 0x0000000000001aab): DW_OP_reg14 R14
                   [0x0000000000001aab, 0x0000000000001aba):
DW_OP_entry_value(D
W_OP_reg8 R8), DW_OP_stack_value
                   [0x0000000000001aba, 0x0000000000001b1b): DW_OP_reg14 R14
                   [0x0000000000000000, 0x00000000000000bd): DW_OP_reg14 R14)
                DW_AT_unknown_2137      (0x000070a9)

0x00019269:   DW_TAG_formal_parameter
                DW_AT_abstract_origin   (0x00014289 "warnlvl")
                DW_AT_location  (0x000070f4: 
                   [0x0000000000001990, 0x00000000000019f0): DW_OP_reg9 R9
                   [0x00000000000019f0, 0x0000000000001aba): DW_OP_fbreg -72
                   [0x0000000000001aba, 0x0000000000001adc): DW_OP_reg9 R9
                   [0x0000000000001adc, 0x0000000000001b1b): DW_OP_fbreg -72
                   [0x0000000000001b1b, 0x0000000000001b1b): DW_OP_reg9 R9
                   [0x0000000000000000, 0x000000000000000d): DW_OP_reg9 R9
                   [0x000000000000000d, 0x00000000000000bd): DW_OP_fbreg -72)
                DW_AT_unknown_2137      (0x000070e6)

  parent reply	other threads:[~2021-11-16 16:18 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-15  1:17 [Bug debug/103241] New: " wcohen at redhat dot com
2021-11-16 14:11 ` [Bug debug/103241] " jakub at gcc dot gnu.org
2021-11-16 14:46 ` wcohen at redhat dot com
2021-11-16 14:51 ` wcohen at redhat dot com
2021-11-16 15:11 ` marxin at gcc dot gnu.org
2021-11-16 15:24 ` wcohen at redhat dot com
2021-11-16 15:39 ` marxin at gcc dot gnu.org
2021-11-16 16:18 ` wcohen at redhat dot com [this message]
2021-11-18 10:24 ` marxin at gcc dot gnu.org
2021-11-18 10:35 ` jakub at gcc dot gnu.org
2021-11-18 15:11 ` wcohen at redhat dot com
2021-11-18 15:23 ` jakub at gcc dot gnu.org
2021-11-18 16:00 ` wcohen at redhat dot com
2021-11-18 16:18 ` jakub at gcc dot gnu.org
2021-11-19 10:18 ` aoliva at gcc dot gnu.org

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