[lld] r303089 - ELF: --gdb-index: Change findSection to return an InputSection.
Peter Collingbourne via llvm-commits
llvm-commits at lists.llvm.org
Mon May 15 10:59:22 PDT 2017
Author: pcc
Date: Mon May 15 12:59:21 2017
New Revision: 303089
URL: http://llvm.org/viewvc/llvm-project?rev=303089&view=rev
Log:
ELF: --gdb-index: Change findSection to return an InputSection.
We should only ever expect this function to return a regular
InputSection; I would not expect a function definition to be in a
MergeInputSection or EhInputSection. We were previously crashing
in writeTo if this function returned a section that was not an
InputSection because we do not set OutSec for such sections.
This can happen in practice if a function is defined in an empty
section which shares its offset-in-file with a MergeInputSection,
as in the provided test case.
A better fix for this bug would be to fix the
DWARFUnit::collectAddressRanges() interface to provide section
information (see D33183), but this at least fixes the crash.
Differential Revision: https://reviews.llvm.org/D33176
Added:
lld/trunk/test/ELF/gdb-index-empty.s
Modified:
lld/trunk/ELF/GdbIndex.h
lld/trunk/ELF/SyntheticSections.cpp
Modified: lld/trunk/ELF/GdbIndex.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/GdbIndex.h?rev=303089&r1=303088&r2=303089&view=diff
==============================================================================
--- lld/trunk/ELF/GdbIndex.h (original)
+++ lld/trunk/ELF/GdbIndex.h Mon May 15 12:59:21 2017
@@ -21,7 +21,7 @@ class InputSection;
// Struct represents single entry of address area of gdb index.
struct AddressEntry {
- InputSectionBase *Section;
+ InputSection *Section;
uint64_t LowAddress;
uint64_t HighAddress;
size_t CuIndex;
Modified: lld/trunk/ELF/SyntheticSections.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/SyntheticSections.cpp?rev=303089&r1=303088&r2=303089&view=diff
==============================================================================
--- lld/trunk/ELF/SyntheticSections.cpp (original)
+++ lld/trunk/ELF/SyntheticSections.cpp Mon May 15 12:59:21 2017
@@ -1701,13 +1701,14 @@ readCuList(DWARFContext &Dwarf, InputSec
return Ret;
}
-static InputSectionBase *findSection(ArrayRef<InputSectionBase *> Arr,
- uint64_t Offset) {
+static InputSection *findSection(ArrayRef<InputSectionBase *> Arr,
+ uint64_t Offset) {
for (InputSectionBase *S : Arr)
- if (S && S != &InputSection::Discarded && S->Live)
- if (Offset >= S->getOffsetInFile() &&
- Offset < S->getOffsetInFile() + S->getSize())
- return S;
+ if (auto *IS = dyn_cast_or_null<InputSection>(S))
+ if (IS != &InputSection::Discarded && IS->Live &&
+ Offset >= IS->getOffsetInFile() &&
+ Offset < IS->getOffsetInFile() + IS->getSize())
+ return IS;
return nullptr;
}
@@ -1721,7 +1722,7 @@ readAddressArea(DWARFContext &Dwarf, Inp
ArrayRef<InputSectionBase *> Sections = Sec->File->getSections();
for (std::pair<uint64_t, uint64_t> &R : Ranges)
- if (InputSectionBase *S = findSection(Sections, R.first))
+ if (InputSection *S = findSection(Sections, R.first))
Ret.push_back({S, R.first - S->getOffsetInFile(),
R.second - S->getOffsetInFile(), CurrentCU});
++CurrentCU;
Added: lld/trunk/test/ELF/gdb-index-empty.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/gdb-index-empty.s?rev=303089&view=auto
==============================================================================
--- lld/trunk/test/ELF/gdb-index-empty.s (added)
+++ lld/trunk/test/ELF/gdb-index-empty.s Mon May 15 12:59:21 2017
@@ -0,0 +1,116 @@
+# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux -o %t %s
+# RUN: ld.lld --gdb-index --gc-sections -o %t2 %t
+# RUN: llvm-dwarfdump -debug-dump=gdb_index %t2 | FileCheck %s
+
+# CHECK: Address area offset = 0x28, has 0 entries:
+
+# Generated with: (clang r302976)
+# echo "void _start() { __builtin_unreachable(); }" | \
+# clang -Os -g -S -o gdb-index-empty.s -x c - -Xclang -fdebug-compilation-dir -Xclang .
+
+ .text
+ .file "-"
+ .globl _start
+ .type _start, at function
+_start: # @_start
+.Lfunc_begin0:
+ .cfi_startproc
+# BB#0: # %entry
+.Lfunc_end0:
+ .size _start, .Lfunc_end0-_start
+ .cfi_endproc
+
+ .file 1 "<stdin>"
+ .section .debug_str,"MS", at progbits,1
+.Linfo_string0:
+ .asciz "clang version 5.0.0 " # string offset=0
+.Linfo_string1:
+ .asciz "-" # string offset=21
+.Linfo_string2:
+ .asciz "." # string offset=23
+.Linfo_string3:
+ .asciz "_start" # string offset=25
+ .section .debug_loc,"", at progbits
+ .section .debug_abbrev,"", at progbits
+ .byte 1 # Abbreviation Code
+ .byte 17 # DW_TAG_compile_unit
+ .byte 1 # DW_CHILDREN_yes
+ .byte 37 # DW_AT_producer
+ .byte 14 # DW_FORM_strp
+ .byte 19 # DW_AT_language
+ .byte 5 # DW_FORM_data2
+ .byte 3 # DW_AT_name
+ .byte 14 # DW_FORM_strp
+ .byte 16 # DW_AT_stmt_list
+ .byte 23 # DW_FORM_sec_offset
+ .byte 27 # DW_AT_comp_dir
+ .byte 14 # DW_FORM_strp
+ .byte 17 # DW_AT_low_pc
+ .byte 1 # DW_FORM_addr
+ .byte 18 # DW_AT_high_pc
+ .byte 6 # DW_FORM_data4
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+ .byte 2 # Abbreviation Code
+ .byte 46 # DW_TAG_subprogram
+ .byte 0 # DW_CHILDREN_no
+ .byte 17 # DW_AT_low_pc
+ .byte 1 # DW_FORM_addr
+ .byte 18 # DW_AT_high_pc
+ .byte 6 # DW_FORM_data4
+ .byte 64 # DW_AT_frame_base
+ .byte 24 # DW_FORM_exprloc
+ .byte 3 # DW_AT_name
+ .byte 14 # DW_FORM_strp
+ .byte 58 # DW_AT_decl_file
+ .byte 11 # DW_FORM_data1
+ .byte 59 # DW_AT_decl_line
+ .byte 11 # DW_FORM_data1
+ .byte 63 # DW_AT_external
+ .byte 25 # DW_FORM_flag_present
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+ .byte 0 # EOM(3)
+ .section .debug_info,"", at progbits
+.Lcu_begin0:
+ .long 60 # Length of Unit
+ .short 4 # DWARF version number
+ .long .debug_abbrev # Offset Into Abbrev. Section
+ .byte 8 # Address Size (in bytes)
+ .byte 1 # Abbrev [1] 0xb:0x35 DW_TAG_compile_unit
+ .long .Linfo_string0 # DW_AT_producer
+ .short 12 # DW_AT_language
+ .long .Linfo_string1 # DW_AT_name
+ .long .Lline_table_start0 # DW_AT_stmt_list
+ .long .Linfo_string2 # DW_AT_comp_dir
+ .quad .Lfunc_begin0 # DW_AT_low_pc
+ .long .Lfunc_end0-.Lfunc_begin0 # DW_AT_high_pc
+ .byte 2 # Abbrev [2] 0x2a:0x15 DW_TAG_subprogram
+ .quad .Lfunc_begin0 # DW_AT_low_pc
+ .long .Lfunc_end0-.Lfunc_begin0 # DW_AT_high_pc
+ .byte 1 # DW_AT_frame_base
+ .byte 87
+ .long .Linfo_string3 # DW_AT_name
+ .byte 1 # DW_AT_decl_file
+ .byte 1 # DW_AT_decl_line
+ # DW_AT_external
+ .byte 0 # End Of Children Mark
+ .section .debug_ranges,"", at progbits
+ .section .debug_macinfo,"", at progbits
+.Lcu_macro_begin0:
+ .byte 0 # End Of Macro List Mark
+ .section .debug_pubnames,"", at progbits
+ .long .LpubNames_end0-.LpubNames_begin0 # Length of Public Names Info
+.LpubNames_begin0:
+ .short 2 # DWARF Version
+ .long .Lcu_begin0 # Offset of Compilation Unit Info
+ .long 64 # Compilation Unit Length
+ .long 42 # DIE offset
+ .asciz "_start" # External Name
+ .long 0 # End Mark
+.LpubNames_end0:
+
+ .ident "clang version 5.0.0 "
+ .section ".note.GNU-stack","", at progbits
+ .section .debug_line,"", at progbits
+.Lline_table_start0:
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