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[lldb/DWARF] Fix hostname-stripping logic 

This bit of code is trying to strip everything up to the first colon
from all debug info paths, as dwarf2 recommends this syntax for storing
the compilation host name. However, this code was too eager, and it
ended up stripping the entire compilation directory, if it did not
contain a forward slash (or a "x:\").

Normally this does not matter, as all absolute paths will contain one of
these patterns, but this does not have to be the case in case the debug
info is produced by "clang -fdebug-compilation-dir", which can end up
producing a relative compilation directory with no slashes (this is one
of the techniques for producing "relocatable" debug info).
This commit is contained in:
Pavel Labath 2019-12-23 14:33:00 +01:00
parent 8d6f59b78a
commit 46f02fc922
2 changed files with 51 additions and 0 deletions
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2
lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp
View File

@ -718,6 +718,8 @@ FileSpec DWARFUnit::GetFile(size_t file_idx) {
// Remove the host part if present.
static llvm::StringRef
removeHostnameFromPathname(llvm::StringRef path_from_dwarf) {
if (!path_from_dwarf.contains(':'))
return path_from_dwarf;
llvm::StringRef host, path;
std::tie(host, path) = path_from_dwarf.split(':');

49
lldb/test/Shell/SymbolFile/DWARF/debug_line-relative_path.s Normal file
View File

@ -0,0 +1,49 @@
# This tests handling of debug info with fully relative paths, such as those
# produced by "clang -fdebug-compilation-dir <something-relative>". This is one
# of the techniques used to produce "relocatable" debug info.
# REQUIRES: x86
# RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux -o %t %s
# RUN: %lldb %t -o "image dump line-table t.c" | FileCheck %s
# CHECK: 0x0000000000000000: {{q[\\/]w[\\/]e[\\/]r[\\/]t}}.c:1
.text
main:
.file 1 "w/e/r" "t.c"
.loc 1 1 0 # w/e/r/t.c:1:0
retq
.section .debug_abbrev,"",@progbits
.byte 1 # Abbreviation Code
.byte 17 # DW_TAG_compile_unit
.byte 0 # DW_CHILDREN_no
.byte 37 # DW_AT_producer
.byte 8 # DW_FORM_string
.byte 3 # DW_AT_name
.byte 8 # DW_FORM_string
.byte 16 # DW_AT_stmt_list
.byte 23 # DW_FORM_sec_offset
.byte 27 # DW_AT_comp_dir
.byte 8 # DW_FORM_string
.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 4 # DWARF version number
.long .debug_abbrev # Offset Into Abbrev. Section
.byte 8 # Address Size (in bytes)
.byte 1 # Abbrev [1] 0xb:0x40 DW_TAG_compile_unit
.asciz "Hand-written DWARF" # DW_AT_producer
.asciz "w/e/r/t.c" # DW_AT_name
.long .Lline_table_start0 # DW_AT_stmt_list
.asciz "q" # DW_AT_comp_dir
.Ldebug_info_end0:
.section .debug_line,"",@progbits
.Lline_table_start0: