[Lldb-commits] [lldb] f69f923 - [lldb/DWARF] Fix DW_AT_addr_base & DW_AT_low_pc interaction
Pavel Labath via lldb-commits
lldb-commits at lists.llvm.org
Fri Dec 6 01:46:37 PST 2019
Author: Pavel Labath
Date: 2019-12-06T10:33:13+01:00
New Revision: f69f92344adaada1f8f3cfcd711037227432b062
URL: https://github.com/llvm/llvm-project/commit/f69f92344adaada1f8f3cfcd711037227432b062
DIFF: https://github.com/llvm/llvm-project/commit/f69f92344adaada1f8f3cfcd711037227432b062.diff
LOG: [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.
Added:
lldb/test/Shell/SymbolFile/DWARF/DW_AT_low_pc-addrx.s
Modified:
lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp
Removed:
################################################################################
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp
index 35f5c30e1778..072cbc2abc3a 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp
@@ -287,16 +287,25 @@ void DWARFUnit::AddUnitDIE(const DWARFDebugInfoEntry &cu_die) {
DWARFAttributes 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) {
dw_attr_t attr = attributes.AttributeAtIndex(i);
DWARFFormValue form_value;
if (!attributes.ExtractFormValueAtIndex(i, form_value))
continue;
switch (attr) {
- case DW_AT_addr_base:
- addr_base = form_value.Unsigned();
- SetAddrBase(*addr_base);
- break;
case DW_AT_rnglists_base:
ranges_base = form_value.Unsigned();
SetRangesBase(*ranges_base);
diff --git a/lldb/test/Shell/SymbolFile/DWARF/DW_AT_low_pc-addrx.s b/lldb/test/Shell/SymbolFile/DWARF/DW_AT_low_pc-addrx.s
new file mode 100644
index 000000000000..df089668cd96
--- /dev/null
+++ b/lldb/test/Shell/SymbolFile/DWARF/DW_AT_low_pc-addrx.s
@@ -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,"", at 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,"", at 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,"", at 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,"", at 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:
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