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[lldb] Add omitted abstract formal parameters in DWARF symbol files

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This patch fixes a problem introduced by clang change
https://reviews.llvm.org/D95617 and described by
https://bugs.llvm.org/show_bug.cgi?id=50076#c6, where inlined functions
omit unused parameters both in the stack trace and in `frame var`
command. With this patch, the parameters are listed correctly in the
stack trace and in `frame var` command.

Specifically, we parse formal parameters from the abstract version of
inlined functions and use those formal parameters if they are missing
from the concrete version.

Differential Revision: https://reviews.llvm.org/D110571
This commit is contained in:
Jaroslav Sevcik
2021-09-25 19:29:04 +02:00
committed by Jaroslav Sevcik
parent 9ba5bb4309
commit 5a3556aa55
7 changed files with 704 additions and 53 deletions
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458
lldb/test/Shell/SymbolFile/DWARF/x86/Inputs/unused-inlined-params.s Normal file
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# The below program is roughly derived from the following C program.
# To see the annotated debug info, look for the section
# '.section .debug_info' below.
#
# __attribute__((always_inline))
# void f(void* unused1, int used, int unused2, int partial, int unused3) {
# used += partial;
# printf("f %i", partial);
# printf("f %i", used); // |partial| is not live at this line.
# }
#
# void g(int unused) {
# printf("Hello");
# }
#
# __attribute__((noinline))
# void other() {
# f(nullptr, 1, 0, 2, 0);
# }
#
# int main(int argc, char** argv) {
# f(argv, 42, 1, argc, 2);
# g(1);
# other();
# return 0;
# }
.text
.file "unused-inlined-params.c"
.Lcu_begin:
.globl other
other:
nop
.Linlined_f_in_other:
break_at_inlined_f_in_other:
callq printf # Omitted the setup of arguments.
.Linlined_f_in_other_between_printfs:
callq printf # Omitted the setup of arguments.
.Linlined_f_in_other_end:
retq
.Lother_end:
.size other, .Lother_end-other
.globl main
main:
.file 1 "/example" "unused-inlined-params.c"
movl $1, %esi
.Linlined_f:
break_at_inlined_f_in_main:
leal 42(%rsi), %ebx
.Linlined_f_before_printf:
callq printf # Omitted the setup of arguments.
.Linlined_f_between_printfs:
break_at_inlined_f_in_main_between_printfs:
callq printf # Omitted the setup of arguments.
.Linlined_f_end:
.Linlined_g:
break_at_inlined_g_in_main:
callq printf # Omitted the setup of arguments.
.Linlined_g_end:
callq other
retq
.Lmain_end:
.size main, .Lmain_end-main
# Dummy printf implementation.
printf:
retq
# Simple entry point to make the linker happy.
.globl _start
_start:
jmp main
.Lcu_end:
.section .debug_loc,"",@progbits
.Ldebug_loc_partial:
.quad .Linlined_f-.Lcu_begin
.quad .Linlined_f_between_printfs-.Lcu_begin
.short 1 # Loc expr size
.byte 84 # super-register DW_OP_reg4
.quad 0
.quad 0
.Ldebug_loc_used:
.quad .Linlined_f-.Lcu_begin
.quad .Linlined_f_before_printf-.Lcu_begin
.short 3 # Loc expr size
.byte 17 # DW_OP_consts
.byte 42 # value
.byte 159 # DW_OP_stack_value
.quad .Linlined_f_before_printf-.Lcu_begin
.quad .Linlined_f_end-.Lcu_begin
.short 1 # Loc expr size
.byte 83 # super-register DW_OP_reg3
.quad 0
.quad 0
.Ldebug_loc_partial_in_other:
.quad .Linlined_f_in_other-.Lcu_begin
.quad .Linlined_f_in_other_between_printfs-.Lcu_begin
.short 3 # Loc expr size
.byte 17 # DW_OP_consts
.byte 2 # value
.byte 159 # DW_OP_stack_value
.quad 0
.quad 0
.Ldebug_loc_used_in_other:
.quad .Linlined_f_in_other-.Lcu_begin
.quad .Linlined_f_in_other_end-.Lcu_begin
.short 3 # Loc expr size
.byte 17 # DW_OP_consts
.byte 1 # value
.byte 159 # DW_OP_stack_value
.quad 0
.quad 0
.section .debug_abbrev,"",@progbits
.byte 1 # Abbreviation Code
.byte 17 # DW_TAG_compile_unit
.byte 1 # DW_CHILDREN_yes
.byte 3 # DW_AT_name
.byte 14 # DW_FORM_strp
.byte 16 # DW_AT_stmt_list
.byte 23 # DW_FORM_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 0 # EOM(1)
.byte 0 # EOM(2)
.byte 4 # 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 49 # DW_AT_abstract_origin
.byte 19 # DW_FORM_ref4
.byte 0 # EOM(1)
.byte 0 # EOM(2)
.byte 5 # 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 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 6 # Abbreviation Code
.byte 5 # DW_TAG_formal_parameter
.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 73 # DW_AT_type
.byte 19 # DW_FORM_ref4
.byte 0 # EOM(1)
.byte 0 # EOM(2)
.byte 7 # Abbreviation Code
.byte 15 # DW_TAG_pointer_type
.byte 0 # DW_CHILDREN_no
.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 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 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 10 # 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 11 # Abbreviation Code
.byte 29 # DW_TAG_inlined_subroutine
.byte 1 # DW_CHILDREN_yes
.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 12 # 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 0 # EOM(3)
.section .debug_info,"",@progbits
.Ldi_cu_begin:
.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] DW_TAG_compile_unit
.long .Linfo_string_fname # DW_AT_name
.long .Lline_table_start0 # DW_AT_stmt_list
.quad .Lcu_begin # DW_AT_low_pc
.long .Lcu_end-.Lcu_begin # DW_AT_high_pc
# Debug info for |f| (abstract version with all parameters).
.Ldebug_info_f:
.byte 5 # Abbrev [5] DW_TAG_subprogram
.long .Linfo_string_f # DW_AT_name
.byte 1 # DW_AT_decl_file
.byte 4 # DW_AT_decl_line
# DW_AT_prototyped
# DW_AT_external
.byte 1 # DW_AT_inline
.Ldebug_info_param1:
.byte 6 # Abbrev [6] DW_TAG_formal_parameter
.long .Linfo_string_unused1 # DW_AT_name
.byte 1 # DW_AT_decl_file
.byte 4 # DW_AT_decl_line
.long .Ldebug_info_void_ptr-.Ldi_cu_begin
# DW_AT_type
.Ldebug_info_param2:
.byte 6 # Abbrev [6] DW_TAG_formal_parameter
.long .Linfo_string_used # DW_AT_name
.byte 1 # DW_AT_decl_file
.byte 4 # DW_AT_decl_line
.long .Ldebug_info_int-.Ldi_cu_begin # DW_AT_type
.Ldebug_info_param3:
.byte 6 # Abbrev [6] DW_TAG_formal_parameter
.long .Linfo_string_unused2 # DW_AT_name
.byte 1 # DW_AT_decl_file
.byte 4 # DW_AT_decl_line
.long .Ldebug_info_int-.Ldi_cu_begin # DW_AT_type
.Ldebug_info_param4:
.byte 6 # Abbrev [6] DW_TAG_formal_parameter
.long .Linfo_string_partial # DW_AT_name
.byte 1 # DW_AT_decl_file
.byte 4 # DW_AT_decl_line
.long .Ldebug_info_int-.Ldi_cu_begin # DW_AT_type
.Ldebug_info_param5:
.byte 6 # Abbrev [6] DW_TAG_formal_parameter
.long .Linfo_string_unused3 # DW_AT_name
.byte 1 # DW_AT_decl_file
.byte 4 # DW_AT_decl_line
.long .Ldebug_info_int-.Ldi_cu_begin # DW_AT_type
.byte 0 # End Of Children Mark (DW_TAG_subprogram)
# Debug info for |g| (abstract version with all parameters).
.Ldebug_info_g:
.byte 5 # Abbrev [5] DW_TAG_subprogram
.long .Linfo_string_g # DW_AT_name
.byte 1 # DW_AT_decl_file
.byte 4 # DW_AT_decl_line
# DW_AT_prototyped
# DW_AT_external
.byte 1 # DW_AT_inline
.Ldebug_info_g_param1:
.byte 6 # Abbrev [6] DW_TAG_formal_parameter
.long .Linfo_string_unused # DW_AT_name
.byte 1 # DW_AT_decl_file
.byte 10 # DW_AT_decl_line
.long .Ldebug_info_int-.Ldi_cu_begin
.byte 0 # End Of Children Mark (DW_TAG_subprogram)
# Debug info for |main|.
.byte 9 # Abbrev [9] DW_TAG_subprogram
.quad main # DW_AT_low_pc
.long .Lmain_end-main # DW_AT_high_pc
.byte 1 # DW_AT_frame_base
.byte 87
.long .Linfo_string_main # DW_AT_name
.byte 1 # DW_AT_decl_file
.byte 18 # DW_AT_decl_line
# DW_AT_prototyped
.long .Ldebug_info_int-.Ldi_cu_begin # DW_AT_type
# DW_AT_external
# Debug info for concrete |f| inlined into |main|.
.byte 11 # Abbrev [11] DW_TAG_inlined_subroutine
.long .Ldebug_info_f-.Ldi_cu_begin
# DW_AT_abstract_origin
.quad .Linlined_f # DW_AT_low_pc
.long .Linlined_f_end-.Linlined_f # DW_AT_high_pc
.byte 1 # DW_AT_call_file
.byte 20 # DW_AT_call_line
.byte 3 # DW_AT_call_column
.byte 4 # Abbrev [4] DW_TAG_formal_parameter
.long .Ldebug_loc_used # DW_AT_location
.long .Ldebug_info_param2-.Ldi_cu_begin
# DW_AT_abstract_origin
.byte 4 # Abbrev [4] DW_TAG_formal_parameter
.long .Ldebug_loc_partial # DW_AT_location
.long .Ldebug_info_param4-.Ldi_cu_begin
# DW_AT_abstract_origin
.byte 0 # End Of Children Mark (DW_TAG_inlined_subroutine)
# Debug info for concrete |g| inlined into |main|.
.byte 11 # Abbrev [11] DW_TAG_inlined_subroutine
.long .Ldebug_info_g-.Ldi_cu_begin
# DW_AT_abstract_origin
.quad .Linlined_g # DW_AT_low_pc
.long .Linlined_g_end-.Linlined_g # DW_AT_high_pc
.byte 1 # DW_AT_call_file
.byte 21 # DW_AT_call_line
.byte 3 # DW_AT_call_column
.byte 0 # End Of Children Mark (DW_TAG_inlined_subroutine)
.byte 0 # End Of Children Mark (DW_TAG_subprogram)
# Debug info for |other|.
.byte 9 # Abbrev [9] DW_TAG_subprogram
.quad other # DW_AT_low_pc
.long .Lother_end-other # DW_AT_high_pc
.byte 1 # DW_AT_frame_base
.byte 87
.long .Linfo_string_other # DW_AT_name
.byte 1 # DW_AT_decl_file
.byte 15 # DW_AT_decl_line
# DW_AT_prototyped
.long .Ldebug_info_int-.Ldi_cu_begin # DW_AT_type
# DW_AT_external
# Debug info for concrete |f| inlined into |other|.
.byte 11 # Abbrev [11] DW_TAG_inlined_subroutine
.long .Ldebug_info_f-.Ldi_cu_begin
# DW_AT_abstract_origin
.quad .Linlined_f_in_other # DW_AT_low_pc
.long .Linlined_f_in_other_end-.Linlined_f_in_other
# DW_AT_high_pc
.byte 1 # DW_AT_call_file
.byte 16 # DW_AT_call_line
.byte 3 # DW_AT_call_column
.byte 4 # Abbrev [4] DW_TAG_formal_parameter
.long .Ldebug_loc_used_in_other # DW_AT_location
.long .Ldebug_info_param2-.Ldi_cu_begin
# DW_AT_abstract_origin
.byte 4 # Abbrev [4] DW_TAG_formal_parameter
.long .Ldebug_loc_partial_in_other # DW_AT_location
.long .Ldebug_info_param4-.Ldi_cu_begin
# DW_AT_abstract_origin
.byte 0 # End Of Children Mark (DW_TAG_inlined_subroutine)
.byte 0 # End Of Children Mark (DW_TAG_subprogram)
.Ldebug_info_void_ptr:
.byte 7 # Abbrev [7] DW_TAG_pointer_type
.Ldebug_info_int:
.byte 8 # Abbrev [8] DW_TAG_base_type
.long .Linfo_string_int # DW_AT_name
.byte 5 # DW_AT_encoding
.byte 4 # DW_AT_byte_size
.byte 0 # End Of Children Mark (DW_TAG_compile_unit)
.Ldebug_info_end0:
.section .debug_str,"MS",@progbits,1
.Linfo_string_fname:
.asciz "unused-inlined-params.c"
.Linfo_string_f:
.asciz "f"
.Linfo_string_unused1:
.asciz "unused1"
.Linfo_string_used:
.asciz "used"
.Linfo_string_int:
.asciz "int"
.Linfo_string_unused2:
.asciz "unused2"
.Linfo_string_partial:
.asciz "partial"
.Linfo_string_unused3:
.asciz "unused3"
.Linfo_string_main:
.asciz "main"
.Linfo_string_g:
.asciz "g"
.Linfo_string_unused:
.asciz "unused"
.Linfo_string_other:
.asciz "other"
.section ".note.GNU-stack","",@progbits
.addrsig
.section .debug_line,"",@progbits
.Lline_table_start0:

48
lldb/test/Shell/SymbolFile/DWARF/x86/unused-inlined-params.test Normal file
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@@ -0,0 +1,48 @@
# RUN: llvm-mc -filetype=obj %S/Inputs/unused-inlined-params.s \
# RUN: -triple x86_64-pc-linux -o %t.o
# RUN: %lldb %t.o -s %s -o exit | FileCheck %s
# In this test we verify that inlined functions still mention
# all their parameters in `frame variable`, even when those
# parameters were completely optimized away from the concrete
# instance of the inlined function in the debug info.
# The debugger should look up the parameters in the abstract
# origin of the concrete instance.
# Let us check that unused parameters of an inlined function are listed
# at the inlined function entry.
image lookup -v -s break_at_inlined_f_in_main
# CHECK-LABEL: image lookup -v -s break_at_inlined_f_in_main
# CHECK: name = "unused1", type = "void *", location = <empty>
# CHECK: name = "used", type = "int", location = DW_OP_consts +42
# CHECK: name = "unused2", type = "int", location = <empty>
# CHECK: name = "partial", type = "int", location = DW_OP_reg4 RSI
# CHECK: name = "unused3", type = "int", location = <empty>
# Show variables outsid of the live range of the 'partial' parameter
# and verify that the output is as expected.
image lookup -v -s break_at_inlined_f_in_main_between_printfs
# CHECK-LABEL: image lookup -v -s break_at_inlined_f_in_main_between_printfs
# CHECK: name = "unused1", type = "void *", location = <empty>
# CHECK: name = "used", type = "int", location = DW_OP_reg3 RBX
# CHECK: name = "unused2", type = "int", location = <empty>
# Note: image lookup does not show variables outside of their
# location, so |partial| is missing here.
# CHECK-NOT: partial
# CHECK: name = "unused3", type = "int", location = <empty>
# Check that we show parameters even if all of them are compiled away.
image lookup -v -s break_at_inlined_g_in_main
# CHECK-LABEL: image lookup -v -s break_at_inlined_g_in_main
# CHECK: name = "unused", type = "int", location = <empty>
# Check that even the other inlined instance of f displays the correct
# parameters.
image lookup -v -s break_at_inlined_f_in_other
# CHECK-LABEL: image lookup -v -s break_at_inlined_f_in_other
# CHECK: name = "unused1", type = "void *", location = <empty>
# CHECK: name = "used", type = "int", location = DW_OP_consts +1
# CHECK: name = "unused2", type = "int", location = <empty>
# CHECK: name = "partial", type = "int", location = DW_OP_consts +2
# CHECK: name = "unused3", type = "int", location = <empty>