[llvm] [BOLT][DWARF] Fix output ranges for deleted code (PR #73464)

Maksim Panchenko via llvm-commits llvm-commits at lists.llvm.org
Sun Nov 26 13:59:10 PST 2023


https://github.com/maksfb created https://github.com/llvm/llvm-project/pull/73464

Set range low_pc to 0 for DIEs that correspond to deleted code.

Fixes #73428

>From 646192d1bb04befd95e44967a8c774581e3e32f5 Mon Sep 17 00:00:00 2001
From: Maksim Panchenko <maks at fb.com>
Date: Sun, 26 Nov 2023 13:54:48 -0800
Subject: [PATCH] [BOLT][DWARF] Fix output ranges for deleted code

Set range low_pc to 0 for DIEs that correspond to deleted code.

Fixes #73428
---
 bolt/lib/Rewrite/DWARFRewriter.cpp  |   3 +-
 bolt/test/X86/dwarf-deleted-range.s | 433 ++++++++++++++++++++++++++++
 2 files changed, 434 insertions(+), 2 deletions(-)
 create mode 100644 bolt/test/X86/dwarf-deleted-range.s

diff --git a/bolt/lib/Rewrite/DWARFRewriter.cpp b/bolt/lib/Rewrite/DWARFRewriter.cpp
index 360b82f45bd7754..f137f6603bf1189 100644
--- a/bolt/lib/Rewrite/DWARFRewriter.cpp
+++ b/bolt/lib/Rewrite/DWARFRewriter.cpp
@@ -963,8 +963,7 @@ void DWARFRewriter::updateUnitDebugInfo(
               std::move(OutputRanges), CachedRanges);
           OutputRanges.clear();
         } else if (OutputRanges.empty()) {
-          OutputRanges.push_back({RangesOrError.get().front().LowPC,
-                                  RangesOrError.get().front().HighPC});
+          OutputRanges.push_back({0, RangesOrError.get().front().HighPC});
         }
       } else if (!RangesOrError) {
         consumeError(RangesOrError.takeError());
diff --git a/bolt/test/X86/dwarf-deleted-range.s b/bolt/test/X86/dwarf-deleted-range.s
new file mode 100644
index 000000000000000..b2aa78055f72503
--- /dev/null
+++ b/bolt/test/X86/dwarf-deleted-range.s
@@ -0,0 +1,433 @@
+# REQUIRES: system-linux
+
+# RUN: llvm-mc -dwarf-version=4 -filetype=obj -triple x86_64-unknown-linux %s -o %tmain.o
+# RUN: %clang %cflags -no-pie %s -o %t.exe -Wl,-q
+# RUN: llvm-bolt %t.exe -o %t.bolt --update-debug-sections
+# RUN: llvm-dwarfdump --show-children --name=main --debug-info %t.bolt \
+# RUN:   | FileCheck %s
+
+# CHECK: 		DW_TAG_inlined_subroutine
+# CHECK:      DW_AT_low_pc
+# CHECK-SAME: 0x0000000000000000
+
+# CHECK:    DW_TAG_GNU_call_site
+# CHECK:      DW_AT_low_pc
+# CHECK-SAME: 0x0000000000000000
+
+## Test that llvm-bolt correctly updates DIEs corresponding to deleted code.
+
+# Test case built from the following source using:
+#
+#   clang -O2 -g ...
+#
+# Assembly modified with "je" -> "jmp" to introduce unreachable block.
+#
+# extern void puts(const char *);
+#
+# void foo() {
+#   puts("hi");
+# }
+#
+# int main(int argc, char **argv) {
+#   if (argc)
+#     foo();
+#   return 0;
+# }
+
+	.text
+	.file	"unreachable.c"
+	.globl	foo                             # -- Begin function foo
+	.p2align	4, 0x90
+	.type	foo, at function
+foo:                                    # @foo
+.Lfunc_begin0:
+	.file	1 "." "unreachable.c"
+	.loc	1 3 0                           # unreachable.c:3:0
+	.cfi_startproc
+# %bb.0:
+	.loc	1 4 3 prologue_end              # unreachable.c:4:3
+	movl	$.L.str, %edi
+.Ltmp0:
+	jmp	puts                            # TAILCALL
+.Ltmp1:
+.Lfunc_end0:
+	.size	foo, .Lfunc_end0-foo
+	.cfi_endproc
+                                        # -- End function
+	.globl	main                            # -- Begin function main
+	.p2align	4, 0x90
+	.type	main, at function
+main:                                   # @main
+.Lfunc_begin1:
+	.loc	1 7 0                           # unreachable.c:7:0
+	.cfi_startproc
+# %bb.0:
+	#DEBUG_VALUE: main:argc <- $edi
+	#DEBUG_VALUE: main:argc <- $edi
+	#DEBUG_VALUE: main:argv <- $rsi
+	.loc	1 8 7 prologue_end              # unreachable.c:8:7
+	testl	%edi, %edi
+.Ltmp2:
+	.loc	1 8 7 is_stmt 0                 # unreachable.c:8:7
+	jmp	.LBB1_2
+.Ltmp3:
+# %bb.1:
+	#DEBUG_VALUE: main:argv <- $rsi
+	#DEBUG_VALUE: main:argc <- $edi
+	pushq	%rax
+	.cfi_def_cfa_offset 16
+.Ltmp4:
+	.loc	1 4 3 is_stmt 1                 # unreachable.c:4:3
+	movl	$.L.str, %edi
+.Ltmp5:
+	#DEBUG_VALUE: main:argc <- [DW_OP_LLVM_entry_value 1] $edi
+	callq	puts
+.Ltmp6:
+	#DEBUG_VALUE: main:argv <- [DW_OP_LLVM_entry_value 1] $rsi
+	.loc	1 0 3 is_stmt 0                 # unreachable.c:0:3
+	addq	$8, %rsp
+.Ltmp7:
+	.cfi_def_cfa_offset 8
+.LBB1_2:
+	.loc	1 10 3 is_stmt 1                # unreachable.c:10:3
+	xorl	%eax, %eax
+	retq
+.Ltmp8:
+.Lfunc_end1:
+	.size	main, .Lfunc_end1-main
+	.cfi_endproc
+                                        # -- End function
+	.type	.L.str, at object                  # @.str
+	.section	.rodata.str1.1,"aMS", at progbits,1
+.L.str:
+	.asciz	"hi"
+	.size	.L.str, 3
+
+	.section	.debug_loc,"", at progbits
+.Ldebug_loc0:
+	.quad	.Lfunc_begin1-.Lfunc_begin0
+	.quad	.Ltmp5-.Lfunc_begin0
+	.short	1                               # Loc expr size
+	.byte	85                              # super-register DW_OP_reg5
+	.quad	.Ltmp5-.Lfunc_begin0
+	.quad	.Ltmp7-.Lfunc_begin0
+	.short	4                               # Loc expr size
+	.byte	243                             # DW_OP_GNU_entry_value
+	.byte	1                               # 1
+	.byte	85                              # super-register DW_OP_reg5
+	.byte	159                             # DW_OP_stack_value
+	.quad	0
+	.quad	0
+.Ldebug_loc1:
+	.quad	.Lfunc_begin1-.Lfunc_begin0
+	.quad	.Ltmp6-.Lfunc_begin0
+	.short	1                               # Loc expr size
+	.byte	84                              # DW_OP_reg4
+	.quad	.Ltmp6-.Lfunc_begin0
+	.quad	.Ltmp7-.Lfunc_begin0
+	.short	4                               # Loc expr size
+	.byte	243                             # DW_OP_GNU_entry_value
+	.byte	1                               # 1
+	.byte	84                              # DW_OP_reg4
+	.byte	159                             # DW_OP_stack_value
+	.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
+	.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
+	.ascii	"\227B"                         # DW_AT_GNU_all_call_sites
+	.byte	25                              # DW_FORM_flag_present
+	.byte	49                              # DW_AT_abstract_origin
+	.byte	19                              # DW_FORM_ref4
+	.byte	0                               # EOM(1)
+	.byte	0                               # EOM(2)
+	.byte	3                               # Abbreviation Code
+	.ascii	"\211\202\001"                  # DW_TAG_GNU_call_site
+	.byte	0                               # DW_CHILDREN_no
+	.byte	49                              # DW_AT_abstract_origin
+	.byte	19                              # DW_FORM_ref4
+	.ascii	"\225B"                         # DW_AT_GNU_tail_call
+	.byte	25                              # DW_FORM_flag_present
+	.byte	17                              # DW_AT_low_pc
+	.byte	1                               # DW_FORM_addr
+	.byte	0                               # EOM(1)
+	.byte	0                               # EOM(2)
+	.byte	4                               # Abbreviation Code
+	.byte	46                              # DW_TAG_subprogram
+	.byte	1                               # DW_CHILDREN_yes
+	.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	39                              # DW_AT_prototyped
+	.byte	25                              # DW_FORM_flag_present
+	.byte	60                              # DW_AT_declaration
+	.byte	25                              # DW_FORM_flag_present
+	.byte	63                              # DW_AT_external
+	.byte	25                              # DW_FORM_flag_present
+	.byte	0                               # EOM(1)
+	.byte	0                               # EOM(2)
+	.byte	5                               # Abbreviation Code
+	.byte	5                               # DW_TAG_formal_parameter
+	.byte	0                               # DW_CHILDREN_no
+	.byte	73                              # DW_AT_type
+	.byte	19                              # DW_FORM_ref4
+	.byte	0                               # EOM(1)
+	.byte	0                               # EOM(2)
+	.byte	6                               # Abbreviation Code
+	.byte	15                              # DW_TAG_pointer_type
+	.byte	0                               # DW_CHILDREN_no
+	.byte	73                              # DW_AT_type
+	.byte	19                              # DW_FORM_ref4
+	.byte	0                               # EOM(1)
+	.byte	0                               # EOM(2)
+	.byte	7                               # Abbreviation Code
+	.byte	38                              # DW_TAG_const_type
+	.byte	0                               # DW_CHILDREN_no
+	.byte	73                              # DW_AT_type
+	.byte	19                              # DW_FORM_ref4
+	.byte	0                               # EOM(1)
+	.byte	0                               # EOM(2)
+	.byte	8                               # 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	9                               # Abbreviation Code
+	.byte	46                              # DW_TAG_subprogram
+	.byte	0                               # DW_CHILDREN_no
+	.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	63                              # DW_AT_external
+	.byte	25                              # DW_FORM_flag_present
+	.byte	32                              # DW_AT_inline
+	.byte	11                              # DW_FORM_data1
+	.byte	0                               # EOM(1)
+	.byte	0                               # EOM(2)
+	.byte	10                              # 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
+	.ascii	"\227B"                         # DW_AT_GNU_all_call_sites
+	.byte	25                              # DW_FORM_flag_present
+	.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	39                              # DW_AT_prototyped
+	.byte	25                              # DW_FORM_flag_present
+	.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	11                              # 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	12                              # Abbreviation Code
+	.byte	29                              # DW_TAG_inlined_subroutine
+	.byte	0                               # DW_CHILDREN_no
+	.byte	49                              # DW_AT_abstract_origin
+	.byte	19                              # DW_FORM_ref4
+	.byte	17                              # DW_AT_low_pc
+	.byte	1                               # DW_FORM_addr
+	.byte	18                              # DW_AT_high_pc
+	.byte	6                               # DW_FORM_data4
+	.byte	88                              # DW_AT_call_file
+	.byte	11                              # DW_FORM_data1
+	.byte	89                              # DW_AT_call_line
+	.byte	11                              # DW_FORM_data1
+	.byte	87                              # DW_AT_call_column
+	.byte	11                              # DW_FORM_data1
+	.byte	0                               # EOM(1)
+	.byte	0                               # EOM(2)
+	.byte	13                              # Abbreviation Code
+	.ascii	"\211\202\001"                  # DW_TAG_GNU_call_site
+	.byte	0                               # DW_CHILDREN_no
+	.byte	49                              # DW_AT_abstract_origin
+	.byte	19                              # DW_FORM_ref4
+	.byte	17                              # DW_AT_low_pc
+	.byte	1                               # DW_FORM_addr
+	.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	4                               # DWARF version number
+	.long	.debug_abbrev                   # Offset Into Abbrev. Section
+	.byte	8                               # Address Size (in bytes)
+	.byte	1                               # Abbrev [1] 0xb:0xd1 DW_TAG_compile_unit
+	.long	.Linfo_string0                  # DW_AT_producer
+	.short	12                              # DW_AT_language
+	.long	.Linfo_string1                  # DW_AT_name
+	.long	.Lline_table_start0             # DW_AT_stmt_list
+	.long	.Linfo_string2                  # DW_AT_comp_dir
+	.quad	.Lfunc_begin0                   # DW_AT_low_pc
+	.long	.Lfunc_end1-.Lfunc_begin0       # DW_AT_high_pc
+	.byte	2                               # Abbrev [2] 0x2a:0x21 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
+                                        # DW_AT_GNU_all_call_sites
+	.long	105                             # DW_AT_abstract_origin
+	.byte	3                               # Abbrev [3] 0x3d:0xd DW_TAG_GNU_call_site
+	.long	75                              # DW_AT_abstract_origin
+                                        # DW_AT_GNU_tail_call
+	.quad	.Ltmp1                          # DW_AT_low_pc
+	.byte	0                               # End Of Children Mark
+	.byte	4                               # Abbrev [4] 0x4b:0xd DW_TAG_subprogram
+	.long	.Linfo_string3                  # DW_AT_name
+	.byte	1                               # DW_AT_decl_file
+	.byte	1                               # DW_AT_decl_line
+                                        # DW_AT_prototyped
+                                        # DW_AT_declaration
+                                        # DW_AT_external
+	.byte	5                               # Abbrev [5] 0x52:0x5 DW_TAG_formal_parameter
+	.long	88                              # DW_AT_type
+	.byte	0                               # End Of Children Mark
+	.byte	6                               # Abbrev [6] 0x58:0x5 DW_TAG_pointer_type
+	.long	93                              # DW_AT_type
+	.byte	7                               # Abbrev [7] 0x5d:0x5 DW_TAG_const_type
+	.long	98                              # DW_AT_type
+	.byte	8                               # Abbrev [8] 0x62:0x7 DW_TAG_base_type
+	.long	.Linfo_string4                  # DW_AT_name
+	.byte	6                               # DW_AT_encoding
+	.byte	1                               # DW_AT_byte_size
+	.byte	9                               # Abbrev [9] 0x69:0x8 DW_TAG_subprogram
+	.long	.Linfo_string5                  # DW_AT_name
+	.byte	1                               # DW_AT_decl_file
+	.byte	3                               # DW_AT_decl_line
+                                        # DW_AT_external
+	.byte	1                               # DW_AT_inline
+	.byte	10                              # Abbrev [10] 0x71:0x59 DW_TAG_subprogram
+	.quad	.Lfunc_begin1                   # DW_AT_low_pc
+	.long	.Lfunc_end1-.Lfunc_begin1       # DW_AT_high_pc
+	.byte	1                               # DW_AT_frame_base
+	.byte	87
+                                        # DW_AT_GNU_all_call_sites
+	.long	.Linfo_string6                  # DW_AT_name
+	.byte	1                               # DW_AT_decl_file
+	.byte	7                               # DW_AT_decl_line
+                                        # DW_AT_prototyped
+	.long	202                             # DW_AT_type
+                                        # DW_AT_external
+	.byte	11                              # Abbrev [11] 0x8a:0xf DW_TAG_formal_parameter
+	.long	.Ldebug_loc0                    # DW_AT_location
+	.long	.Linfo_string8                  # DW_AT_name
+	.byte	1                               # DW_AT_decl_file
+	.byte	7                               # DW_AT_decl_line
+	.long	202                             # DW_AT_type
+	.byte	11                              # Abbrev [11] 0x99:0xf DW_TAG_formal_parameter
+	.long	.Ldebug_loc1                    # DW_AT_location
+	.long	.Linfo_string9                  # DW_AT_name
+	.byte	1                               # DW_AT_decl_file
+	.byte	7                               # DW_AT_decl_line
+	.long	209                             # DW_AT_type
+	.byte	12                              # Abbrev [12] 0xa8:0x14 DW_TAG_inlined_subroutine
+	.long	105                             # DW_AT_abstract_origin
+	.quad	.Ltmp4                          # DW_AT_low_pc
+	.long	.Ltmp7-.Ltmp4                   # DW_AT_high_pc
+	.byte	1                               # DW_AT_call_file
+	.byte	9                               # DW_AT_call_line
+	.byte	5                               # DW_AT_call_column
+	.byte	13                              # Abbrev [13] 0xbc:0xd DW_TAG_GNU_call_site
+	.long	75                              # DW_AT_abstract_origin
+	.quad	.Ltmp6                          # DW_AT_low_pc
+	.byte	0                               # End Of Children Mark
+	.byte	8                               # Abbrev [8] 0xca:0x7 DW_TAG_base_type
+	.long	.Linfo_string7                  # DW_AT_name
+	.byte	5                               # DW_AT_encoding
+	.byte	4                               # DW_AT_byte_size
+	.byte	6                               # Abbrev [6] 0xd1:0x5 DW_TAG_pointer_type
+	.long	214                             # DW_AT_type
+	.byte	6                               # Abbrev [6] 0xd6:0x5 DW_TAG_pointer_type
+	.long	98                              # DW_AT_type
+	.byte	0                               # End Of Children Mark
+.Ldebug_info_end0:
+	.section	.debug_str,"MS", at progbits,1
+.Linfo_string0:
+	.asciz	"clang version 12.0.1"          # string offset=0
+.Linfo_string1:
+	.asciz	"unreachable.c"                 # string offset=21
+.Linfo_string2:
+	.asciz	"."                             # string offset=35
+.Linfo_string3:
+	.asciz	"puts"                          # string offset=37
+.Linfo_string4:
+	.asciz	"char"                          # string offset=42
+.Linfo_string5:
+	.asciz	"foo"                           # string offset=47
+.Linfo_string6:
+	.asciz	"main"                          # string offset=51
+.Linfo_string7:
+	.asciz	"int"                           # string offset=56
+.Linfo_string8:
+	.asciz	"argc"                          # string offset=60
+.Linfo_string9:
+	.asciz	"argv"                          # string offset=65
+	.ident	"clang version 12.0.1"
+	.section	".note.GNU-stack","", at progbits
+	.addrsig
+	.section	.debug_line,"", at progbits
+.Lline_table_start0:



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