Handle non-absolute include dirs properly for both dwarf4 and dwarf5.

[saugustine]

Summary

Add test case for the same. This test case will also serve as a
starting point for later symbolizer tests.

[dblaikie]

Hmm - I would've thought there'd be some specific test coverage for this code already that it could be added to for DWARFv5 - but might be lost in the mists of time & this seems good.

[saugustine]

In D73583#1845756, @dblaikie wrote:

Hmm - I would've thought there'd be some specific test coverage for this code already that it could be added to for DWARFv5 - but might be lost in the mists of time & this seems good.

The symbolize-directory test right next to it would be perfect (and, in fact, this code derives from that).

Except it deals with the directory entry zero, which is unallowed in dwarf4 and required in dwarf5, which makes sharing the source file between the two a bit of a pain. It's also testing something important, so needs to stay.

[jhenderson]

I wonder if this is worth unit-testing instead of/in addition to the lit test? The Prologue class should be fairly straightforward to instantiate with the necessary contents, allowing you to test the functionality more directly.

[MaskRay]

llvm/test/DebugInfo/symbolize-paths.s

9

This should look like:

# Absolute include-dirs should not have comp-dir prepended
# CHECK: /absolute{{/|\\}}1.cc:1:0
# Relative include-dirs should have comp-dir prepended	
# CHECK: /comp_dir{{/|\\}}relative{{/|\\}}2.cc:2:1

.file 2 "relative" "2.cc"

The path components are concatenated by \\ on Windows.

thakis has fixed the test.

llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp

bool DWARFDebugLine::Prologue::getFileNameByIndex(
   // Be defensive about the contents of Entry.
   if (getVersion() >= 5) {
     if (Entry.DirIdx < IncludeDirectories.size())
       IncludeDir = IncludeDirectories[Entry.DirIdx].getAsCString().getValue();
   } else {
     if (0 < Entry.DirIdx && Entry.DirIdx <= IncludeDirectories.size())
       IncludeDir =
           IncludeDirectories[Entry.DirIdx - 1].getAsCString().getValue();
-
-    // We may still need to append compilation directory of compile unit.
-    // We know that FileName is not absolute, the only way to have an
-    // absolute path at this point would be if IncludeDir is absolute.
-    if (!CompDir.empty() && !isPathAbsoluteOnWindowsOrPosix(IncludeDir))
-      sys::path::append(FilePath, Style, CompDir);
-  }
+  }
 
   // sys::path::append skips empty strings.
   sys::path::append(FilePath, Style, IncludeDir, FileName);
   Result = std::string(FilePath.str());
   return true;
 }
 
 bool DWARFDebugLine::LineTable::getFileLineInfoForAddress(

llvm/test/DebugInfo/symbolize-paths.s

+# REQUIRES: x86-registered-target
+
+# RUN: llvm-mc -filetype=obj -triple=x86_64 -dwarf-version=4 %s -o %t.o
+# RUN: llvm-symbolizer --obj=%t.o --functions=none 0 1 | FileCheck %s
+# RUN: llvm-mc -filetype=obj -triple=x86_64 -dwarf-version=5 %s -o %t.o
+# RUN: llvm-symbolizer --obj=%t.o --functions=none 0 1 | FileCheck %s
+
+# Absolute include-dirs should not have comp-dir prepended
+# CHECK: /absolute{{/|\\|\\\\}}1.cc:1:0
+# Relative include-dirs should have comp-dir prepended  
+# CHECK: /comp_dir/relative{{/|\\|\\\\}}2.cc:2:1
+
+.Lfunc_begin0:
+  .file 1 "/absolute" "1.cc"
+  .file 2 "relative" "2.cc"
+  .loc 1 1 0                 # 1.cc:1:0
+  nop
+  .loc 2 2 1                 # 2.cc:2:1
+  nop
+  .loc 1 1 1 prologue_end    # 1.cc:1:1
+.Lfunc_end0:
+
+.section .debug_abbrev,"",@progbits
+  .byte 1     # Abbreviation Code
+  .byte 17    # DW_TAG_compile_unit
+  .byte 1     # DW_children_yes
+  .byte 16    # DW_AT_stmt_list
+  .byte 23    # DW_FROM_sec_offset
+  .byte 17    # DW_AT_low_pc
+  .byte 1     # DW_FORM_addr
+  .byte 18    # DW_AT_high_pc
+  .byte 6     # DW_FORM_data4
+  .byte 27    # DW_AT_comp_dir
+  .byte 8     # DW_FORM_string  
+  .byte 0     # EOM(1)
+  .byte 0     # EOM(2)
+
+  .byte 2     # Abbreviation Code
+  .byte 46    # DW_TAG_subprogram
+  .byte 0     # DW_children_no
+  .byte 3     # DW_AT_name
+  .byte 8     # DW_FORM_string
+  .byte 17    # DW_AT_low_pc
+  .byte 1     # DW_FORM_addr
+  .byte 18    # DW_AT_high_pc
+  .byte 6     # DW_FORM_data4
+  .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 .Lcu_end0-.Lcu_begin0-4 # Length of Unit
+  .short 5                      # DWARF version number
+  .byte 1                       # DWARF Unit Type
+  .byte 8                       # Address Size (in bytes)
+  .long .debug_abbrev           # Offset Into Abbrev.
+  .byte 1                       # Abbrev [1]
+  .long 0                       # DW_AT_stmt_list
+  .quad 0                       # DW_AT_low_pc
+  .long 2                       # DW_AT_high_pc
+  .asciz "/comp_dir"            # DW_AT_comp_dir  
+  .byte 2                       # Abbrev [2] DW_TAG_subprogram
+  .asciz "1.c"                  # DW_AT_name
+  .quad 0                       # DW_AT_low_pc
+  .long 2                       # DW_AT_high_pc
+  .asciz "/comp_dir"            # DW_AT_comp_dir  
+  .byte 0
+.Lcu_end0: