maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

[lldb/DWARF] Fix DW_AT_addr_base & DW_AT_low_pc interaction 

In DWARF5 DW_AT_low_pc (and DW_AT_entry_pc, and possibly others) can use
DW_FORM_addrx to refer to the address indirectly. This means we need to
have processed the DW_AT_addr_base attribute before we can do anything
with these.

Since we were processing the unit attributes serially, this created a
problem in cases where the DW_AT_addr_base comes after DW_AT_low_pc --
we would end up computing the wrong unit base address, which also
corrupted any values which later depended on that (for instance range
lists). Clang currently always emits DW_AT_addr_base last.

The fix is simple -- process DW_AT_addr_base first, regardless of its
position in the attribute list.
This commit is contained in:
Pavel Labath 2019-12-05 16:21:23 +01:00
parent b6e2cf3270
commit f69f92344a
2 changed files with 119 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp
View File

@ -287,16 +287,25 @@ void DWARFUnit::AddUnitDIE(const DWARFDebugInfoEntry &cu_die) {
DWARFAttributes attributes; DWARFAttributes attributes;
size_t num_attributes = cu_die.GetAttributes(this, attributes); size_t num_attributes = cu_die.GetAttributes(this, attributes);
// Extract DW_AT_addr_base first, as other attributes may need it.
for (size_t i = 0; i < num_attributes; ++i) {
if (attributes.AttributeAtIndex(i) != DW_AT_addr_base)
continue;
DWARFFormValue form_value;
if (attributes.ExtractFormValueAtIndex(i, form_value)) {
addr_base = form_value.Unsigned();
SetAddrBase(*addr_base);
break;
}
}
for (size_t i = 0; i < num_attributes; ++i) { for (size_t i = 0; i < num_attributes; ++i) {
dw_attr_t attr = attributes.AttributeAtIndex(i); dw_attr_t attr = attributes.AttributeAtIndex(i);
DWARFFormValue form_value; DWARFFormValue form_value;
if (!attributes.ExtractFormValueAtIndex(i, form_value)) if (!attributes.ExtractFormValueAtIndex(i, form_value))
continue; continue;
switch (attr) { switch (attr) {
case DW_AT_addr_base:
addr_base = form_value.Unsigned();
SetAddrBase(*addr_base);
break;
case DW_AT_rnglists_base: case DW_AT_rnglists_base:
ranges_base = form_value.Unsigned(); ranges_base = form_value.Unsigned();
SetRangesBase(*ranges_base); SetRangesBase(*ranges_base);

106
lldb/test/Shell/SymbolFile/DWARF/DW_AT_low_pc-addrx.s Normal file
View File

@ -0,0 +1,106 @@
# REQUIRES: x86
# RUN: llvm-mc -triple=x86_64-pc-linux -filetype=obj %s > %t
# RUN: %lldb %t -o "image lookup -v -s lookup_rnglists" \
# RUN: -o exit | FileCheck %s
# CHECK-LABEL: image lookup -v -s lookup_rnglists
# CHECK: Function: id = {0x7fffffff0000002d}, name = "rnglists", range = [0x0000000000000000-0x0000000000000003)
# CHECK: Blocks: id = {0x7fffffff0000002d}, range = [0x00000000-0x00000003)
# CHECK-NEXT: id = {0x7fffffff00000043}, range = [0x00000001-0x00000002)
.text
rnglists:
nop
.Lblock1_begin:
lookup_rnglists:
nop
.Lblock1_end:
nop
.Lrnglists_end:
.section .debug_abbrev,"",@progbits
.byte 1 # Abbreviation Code
.byte 17 # DW_TAG_compile_unit
.byte 1 # DW_CHILDREN_yes
.byte 37 # DW_AT_producer
.byte 8 # DW_FORM_string
.byte 17 # DW_AT_low_pc
.byte 27 # DW_FORM_addrx
.byte 18 # DW_AT_high_pc
.byte 6 # DW_FORM_data4
.byte 116 # DW_AT_rnglists_base
.byte 23 # DW_FORM_sec_offset
.byte 115 # DW_AT_addr_base
.byte 23 # DW_FORM_sec_offset
.byte 0 # EOM(1)
.byte 0 # EOM(2)
.byte 2 # Abbreviation Code
.byte 46 # DW_TAG_subprogram
.byte 1 # DW_CHILDREN_yes
.byte 17 # DW_AT_low_pc
.byte 1 # DW_FORM_addr
.byte 18 # DW_AT_high_pc
.byte 6 # DW_FORM_data4
.byte 3 # DW_AT_name
.byte 8 # DW_FORM_string
.byte 0 # EOM(1)
.byte 0 # EOM(2)
.byte 5 # Abbreviation Code
.byte 11 # DW_TAG_lexical_block
.byte 0 # DW_CHILDREN_no
.byte 85 # DW_AT_ranges
.byte 35 # DW_FORM_rnglistx
.byte 0 # EOM(1)
.byte 0 # EOM(2)
.byte 0 # EOM(3)
.section .debug_info,"",@progbits
.Lcu_begin0:
.long .Ldebug_info_end0-.Ldebug_info_start0 # Length of Unit
.Ldebug_info_start0:
.short 5 # DWARF version number
.byte 1 # DWARF Unit Type
.byte 8 # Address Size (in bytes)
.long .debug_abbrev # Offset Into Abbrev. Section
.byte 1 # Abbrev [1] 0xc:0x5f DW_TAG_compile_unit
.asciz "Hand-written DWARF" # DW_AT_producer
.byte 0 # DW_AT_low_pc
.long .Lrnglists_end-rnglists # DW_AT_high_pc
.long .Lrnglists_table_base0 # DW_AT_rnglists_base
.long .Laddr_table_base0 # DW_AT_addr_base
.byte 2 # Abbrev [2] 0x2b:0x37 DW_TAG_subprogram
.quad rnglists # DW_AT_low_pc
.long .Lrnglists_end-rnglists # DW_AT_high_pc
.asciz "rnglists" # DW_AT_name
.byte 5 # Abbrev [5] 0x52:0xf DW_TAG_lexical_block
.byte 0 # DW_AT_ranges
.byte 0 # End Of Children Mark
.byte 0 # End Of Children Mark
.Ldebug_info_end0:
.section .debug_addr,"",@progbits
.long .Ldebug_addr_end0-.Ldebug_addr_start0 # Length of contribution
.Ldebug_addr_start0:
.short 5 # DWARF version number
.byte 8 # Address size
.byte 0 # Segment selector size
.Laddr_table_base0:
.quad rnglists
.Ldebug_addr_end0:
.section .debug_rnglists,"",@progbits
.long .Ldebug_rnglist_table_end0-.Ldebug_rnglist_table_start0 # Length
.Ldebug_rnglist_table_start0:
.short 5 # Version
.byte 8 # Address size
.byte 0 # Segment selector size
.long 1 # Offset entry count
.Lrnglists_table_base0:
.long .Ldebug_ranges0-.Lrnglists_table_base0
.Ldebug_ranges0:
.byte 4 # DW_RLE_offset_pair
.uleb128 .Lblock1_begin-rnglists # starting offset
.uleb128 .Lblock1_end-rnglists # ending offset
.byte 0 # DW_RLE_end_of_list
.Ldebug_rnglist_table_end0: