[llvm] r356265 - [llvm] Skip over empty line table entries.

Mircea Trofin via llvm-commits llvm-commits at lists.llvm.org
Fri Mar 15 08:00:12 PDT 2019


Author: mtrofin
Date: Fri Mar 15 08:00:12 2019
New Revision: 356265

URL: http://llvm.org/viewvc/llvm-project?rev=356265&view=rev
Log:
[llvm] Skip over empty line table entries.

Summary:
This is similar to how addr2line handles consecutive entries with the
same address - pick the last one.

Reviewers: dblaikie, friss, JDevlieghere

Reviewed By: dblaikie

Subscribers: eugenis, vitalybuka, echristo, JDevlieghere, probinson, aprantl, hiraditya, rupprecht, jdoerfert, llvm-commits

Tags: #llvm, #debug-info

Differential Revision: https://reviews.llvm.org/D58952

Added:
    llvm/trunk/test/tools/llvm-symbolizer/only-empty-ranges.s
Modified:
    llvm/trunk/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
    llvm/trunk/test/tools/llvm-symbolizer/fission-ranges.test
    llvm/trunk/test/tools/llvm-symbolizer/sym-verbose.test

Modified: llvm/trunk/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/DebugInfo/DWARF/DWARFDebugLine.cpp?rev=356265&r1=356264&r2=356265&view=diff
==============================================================================
--- llvm/trunk/lib/DebugInfo/DWARF/DWARFDebugLine.cpp (original)
+++ llvm/trunk/lib/DebugInfo/DWARF/DWARFDebugLine.cpp Fri Mar 15 08:00:12 2019
@@ -869,17 +869,36 @@ uint32_t DWARFDebugLine::LineTable::find
   RowIter LastRow = Rows.begin() + Seq.LastRowIndex;
   LineTable::RowIter RowPos = std::lower_bound(
       FirstRow, LastRow, Row, DWARFDebugLine::Row::orderByAddress);
-  if (RowPos == LastRow) {
-    return Seq.LastRowIndex - 1;
-  }
+  // Since Address is in Seq, FirstRow <= RowPos < LastRow.
+  assert(FirstRow <= RowPos && RowPos < LastRow);
   assert(Seq.SectionIndex == RowPos->Address.SectionIndex);
-  uint32_t Index = Seq.FirstRowIndex + (RowPos - FirstRow);
-  if (RowPos->Address.Address > Address.Address) {
-    if (RowPos == FirstRow)
-      return UnknownRowIndex;
-    else
-      Index--;
+  if (RowPos->Address.Address != Address.Address) {
+    // lower_bound either lands on the RowPos with the same Address
+    // as the queried one, or on the first that's larger.
+    assert(RowPos->Address.Address > Address.Address);
+    // We know RowPos can't be FirstRow, in this case,
+    // because the queried Address is in Seq. So if it were
+    // FirstRow, then RowPos->Address.Address == Address.Address,
+    // and we wouldn't be here.
+    assert(RowPos != FirstRow);
+    --RowPos;
+  }
+  // In some cases, e.g. first instruction in a function, the compiler generates
+  // two entries, both with the same address. We want the last one.
+  // There are 2 cases wrt. RowPos and the addresses in records before/after it:
+  // 1) RowPos's address is the one we looked for. In this case, we want to
+  // skip any potential empty ranges.
+  // 2) RowPos's address is less than the one we looked for. In that case, we
+  // arrived here by finding the first range with a greater address,
+  // then decrementing 1. If the address of this range is part of a sequence of
+  // empty ones, it is the last one.
+  // In either case, the loop below lands on the correct RowPos.
+  while (RowPos->Address.Address == (RowPos + 1)->Address.Address) {
+    ++RowPos;
   }
+
+  assert(RowPos < LastRow);
+  uint32_t Index = Seq.FirstRowIndex + (RowPos - FirstRow);
   return Index;
 }
 

Modified: llvm/trunk/test/tools/llvm-symbolizer/fission-ranges.test
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/llvm-symbolizer/fission-ranges.test?rev=356265&r1=356264&r2=356265&view=diff
==============================================================================
--- llvm/trunk/test/tools/llvm-symbolizer/fission-ranges.test (original)
+++ llvm/trunk/test/tools/llvm-symbolizer/fission-ranges.test Fri Mar 15 08:00:12 2019
@@ -1,4 +1,4 @@
 RUN: llvm-symbolizer --obj=%p/Inputs/fission-ranges.elf-x86_64 0x720 | FileCheck %s
 
 CHECK: main
-CHECK-NEXT: {{.*}}fission-ranges.cc:6
+CHECK-NEXT: {{.*}}fission-ranges.cc:2

Added: llvm/trunk/test/tools/llvm-symbolizer/only-empty-ranges.s
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/llvm-symbolizer/only-empty-ranges.s?rev=356265&view=auto
==============================================================================
--- llvm/trunk/test/tools/llvm-symbolizer/only-empty-ranges.s (added)
+++ llvm/trunk/test/tools/llvm-symbolizer/only-empty-ranges.s Fri Mar 15 08:00:12 2019
@@ -0,0 +1,221 @@
+# REQUIRES: x86-registered-target
+# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o
+# RUN: llvm-symbolizer 0x0 0x2 0x3 0x4 --obj=%t.o | FileCheck %s
+# This test makes sure we don't attempt to access out of the line table boundaries
+# if the last range is empty.
+# Produced from the following program:
+# int func(int a) {
+#   return 1 + a;
+# }
+# compiled with clang -O3 -g -S
+# Edited by adding a redundant, empty last range.
+# The line table (llvm-dwarfdump --debug-line) looks like:
+#
+# Address            Line   Column File   ISA Discriminator Flags
+# ------------------ ------ ------ ------ --- ------------- -------------
+# 0x0000000000000000      1      0      1   0             0  is_stmt
+# 0x0000000000000000      2     12      1   0             0  is_stmt prologue_end
+# 0x0000000000000003      2      3      1   0             0
+# 0x0000000000000003      3      3      1   0             0
+# 0x0000000000000004      3      3      1   0             0  end_sequence
+#
+# 0x0 should pick the second line in the table - line 2, col 12
+# CHECK:    func
+# CHECK:	/scratch/a.cpp:2:12
+# 0x2 does not exist in the table, so we should pick the line with a
+# lower address that describes the range - in this case, the second line.
+# CHECK:    func
+# CHECK:	/scratch/a.cpp:2:12
+# 0x3 also has a sequence of empty ranges, so we should pick the first range after
+# skipping the empty ones.
+# This also verifies we don't attempt to access outside boundaries.
+# CHECK:    func
+# CHECK:	/scratch/a.cpp:3:3
+# CHECK: ??
+# CHECK: ??:0:0
+
+	.text
+	.file	"a.cpp"
+	.globl	_Z4funci                # -- Begin function _Z4funci
+	.p2align	4, 0x90
+	.type	_Z4funci, at function
+_Z4funci:                               # @_Z4funci
+.Lfunc_begin0:
+	.file	1 "/llvm-project" "/scratch/a.cpp"
+	.loc	1 1 0                   # /scratch/a.cpp:1:0
+	.cfi_startproc
+# %bb.0:
+	#DEBUG_VALUE: func:a <- $edi
+                                        # kill: def $edi killed $edi def $rdi
+	#DEBUG_VALUE: func:a <- $edi
+	.loc	1 2 12 prologue_end     # /scratch/a.cpp:2:12
+	leal	1(%rdi), %eax
+	.loc	1 2 3                   # /scratch/a.cpp:2:3
+    .loc    1 3 3 is_stmt 0         # this forms an empty range torgether with the previous.
+	retq
+.Ltmp0:
+.Lfunc_end0:
+	.size	_Z4funci, .Lfunc_end0-_Z4funci
+	.cfi_endproc
+                                        # -- End function
+	.section	.debug_str,"MS", at progbits,1
+.Linfo_string0:
+	.asciz	"clang version 7.0.1-6 (tags/RELEASE_701/final)" # string offset=0
+.Linfo_string1:
+	.asciz	"/scratch/a.cpp" # string offset=47
+.Linfo_string2:
+	.asciz	"/llvm-project" # string offset=97
+.Linfo_string3:
+	.asciz	"_Z4funci"              # string offset=146
+.Linfo_string4:
+	.asciz	"func"                  # string offset=155
+.Linfo_string5:
+	.asciz	"int"                   # string offset=160
+.Linfo_string6:
+	.asciz	"a"                     # string offset=164
+	.section	.debug_loc,"", at progbits
+.Ldebug_loc0:
+	.quad	.Lfunc_begin0-.Lfunc_begin0
+	.quad	.Lfunc_end0-.Lfunc_begin0
+	.short	1                       # Loc expr size
+	.byte	85                      # super-register DW_OP_reg5
+	.quad	0
+	.quad	0
+	.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
+	.ascii	"\264B"                 # DW_AT_GNU_pubnames
+	.byte	25                      # DW_FORM_flag_present
+	.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	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	64                      # DW_AT_frame_base
+	.byte	24                      # DW_FORM_exprloc
+	.byte	110                     # DW_AT_linkage_name
+	.byte	14                      # DW_FORM_strp
+	.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	73                      # DW_AT_type
+	.byte	19                      # DW_FORM_ref4
+	.byte	63                      # DW_AT_external
+	.byte	25                      # DW_FORM_flag_present
+	.byte	0                       # EOM(1)
+	.byte	0                       # EOM(2)
+	.byte	3                       # Abbreviation Code
+	.byte	5                       # DW_TAG_formal_parameter
+	.byte	0                       # DW_CHILDREN_no
+	.byte	2                       # DW_AT_location
+	.byte	23                      # DW_FORM_sec_offset
+	.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	73                      # DW_AT_type
+	.byte	19                      # DW_FORM_ref4
+	.byte	0                       # EOM(1)
+	.byte	0                       # EOM(2)
+	.byte	4                       # Abbreviation Code
+	.byte	36                      # DW_TAG_base_type
+	.byte	0                       # DW_CHILDREN_no
+	.byte	3                       # DW_AT_name
+	.byte	14                      # DW_FORM_strp
+	.byte	62                      # DW_AT_encoding
+	.byte	11                      # DW_FORM_data1
+	.byte	11                      # DW_AT_byte_size
+	.byte	11                      # DW_FORM_data1
+	.byte	0                       # EOM(1)
+	.byte	0                       # EOM(2)
+	.byte	0                       # EOM(3)
+	.section	.debug_info,"", at progbits
+.Lcu_begin0:
+	.long	91                      # 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:0x54 DW_TAG_compile_unit
+	.long	.Linfo_string0          # DW_AT_producer
+	.short	4                       # DW_AT_language
+	.long	.Linfo_string1          # DW_AT_name
+	.long	.Lline_table_start0     # DW_AT_stmt_list
+	.long	.Linfo_string2          # DW_AT_comp_dir
+                                        # DW_AT_GNU_pubnames
+	.quad	.Lfunc_begin0           # DW_AT_low_pc
+	.long	.Lfunc_end0-.Lfunc_begin0 # DW_AT_high_pc
+	.byte	2                       # Abbrev [2] 0x2a:0x2d 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_linkage_name
+	.long	.Linfo_string4          # DW_AT_name
+	.byte	1                       # DW_AT_decl_file
+	.byte	1                       # DW_AT_decl_line
+	.long	87                      # DW_AT_type
+                                        # DW_AT_external
+	.byte	3                       # Abbrev [3] 0x47:0xf DW_TAG_formal_parameter
+	.long	.Ldebug_loc0            # DW_AT_location
+	.long	.Linfo_string6          # DW_AT_name
+	.byte	1                       # DW_AT_decl_file
+	.byte	1                       # DW_AT_decl_line
+	.long	87                      # DW_AT_type
+	.byte	0                       # End Of Children Mark
+	.byte	4                       # Abbrev [4] 0x57:0x7 DW_TAG_base_type
+	.long	.Linfo_string5          # DW_AT_name
+	.byte	5                       # DW_AT_encoding
+	.byte	4                       # DW_AT_byte_size
+	.byte	0                       # End Of Children Mark
+	.section	.debug_macinfo,"", at progbits
+	.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	95                      # Compilation Unit Length
+	.long	42                      # DIE offset
+	.asciz	"func"                  # External Name
+	.long	0                       # End Mark
+.LpubNames_end0:
+	.section	.debug_pubtypes,"", at progbits
+	.long	.LpubTypes_end0-.LpubTypes_begin0 # Length of Public Types Info
+.LpubTypes_begin0:
+	.short	2                       # DWARF Version
+	.long	.Lcu_begin0             # Offset of Compilation Unit Info
+	.long	95                      # Compilation Unit Length
+	.long	87                      # DIE offset
+	.asciz	"int"                   # External Name
+	.long	0                       # End Mark
+.LpubTypes_end0:
+
+	.ident	"clang version 7.0.1-6 (tags/RELEASE_701/final)"
+	.section	".note.GNU-stack","", at progbits
+	.addrsig
+	.section	.debug_line,"", at progbits
+.Lline_table_start0:

Modified: llvm/trunk/test/tools/llvm-symbolizer/sym-verbose.test
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/llvm-symbolizer/sym-verbose.test?rev=356265&r1=356264&r2=356265&view=diff
==============================================================================
--- llvm/trunk/test/tools/llvm-symbolizer/sym-verbose.test (original)
+++ llvm/trunk/test/tools/llvm-symbolizer/sym-verbose.test Fri Mar 15 08:00:12 2019
@@ -19,8 +19,8 @@ RUN: llvm-symbolizer -verbose -print-add
 #CHECK-NEXT: foo
 #CHECK-NEXT: Filename: /tmp{{[\\/]}}discrim.c
 #CHECK-NEXT: Function start line: 4
-#CHECK-NEXT: Line: 9
-#CHECK-NEXT: Column: 0
+#CHECK-NEXT: Line: 5
+#CHECK-NEXT: Column: 7
 #CHECK-NEXT: main
 #CHECK-NEXT: Filename: /tmp{{[\\/]}}discrim.c
 #CHECK-NEXT: Function start line: 9




More information about the llvm-commits mailing list