[Lldb-commits] [lldb] 16c2872 - Reland "[lldb][DWARFExpression] Fix DW_OP_div to use signed division"
Michael Buch via lldb-commits
lldb-commits at lists.llvm.org
Fri May 5 03:45:19 PDT 2023
Author: LU Hongyi
Date: 2023-05-05T06:45:07-04:00
New Revision: 16c2872d7b09eee67dd0c7ef6b5dd3c3724d3cfc
URL: https://github.com/llvm/llvm-project/commit/16c2872d7b09eee67dd0c7ef6b5dd3c3724d3cfc
DIFF: https://github.com/llvm/llvm-project/commit/16c2872d7b09eee67dd0c7ef6b5dd3c3724d3cfc.diff
LOG: Reland "[lldb][DWARFExpression] Fix DW_OP_div to use signed division"
This patch resolves an issue where a value
is incorrectly displayed if it is represented
by DW_OP_div.
This issue is caused by lldb evaluating
operands of DW_OP_div as unsigned
and performed unintended unsigned
division.
This issue is resolved by creating two
temporary signed scalar and performing
signed division.
(Addresses GH#61727)
Differential Revision: https://reviews.llvm.org/D147370
Added:
lldb/test/Shell/SymbolFile/DWARF/x86/DW_OP_div-with-signed.s
Modified:
lldb/source/Expression/DWARFExpression.cpp
Removed:
################################################################################
diff --git a/lldb/source/Expression/DWARFExpression.cpp b/lldb/source/Expression/DWARFExpression.cpp
index f2ca6534c2fc1..9232282d81353 100644
--- a/lldb/source/Expression/DWARFExpression.cpp
+++ b/lldb/source/Expression/DWARFExpression.cpp
@@ -1436,8 +1436,12 @@ bool DWARFExpression::Evaluate(
return false;
} else {
stack.pop_back();
- stack.back() =
- stack.back().ResolveValue(exe_ctx) / tmp.ResolveValue(exe_ctx);
+ Scalar divisor, dividend;
+ divisor = tmp.ResolveValue(exe_ctx);
+ dividend = stack.back().ResolveValue(exe_ctx);
+ divisor.MakeSigned();
+ dividend.MakeSigned();
+ stack.back() = dividend / divisor;
if (!stack.back().ResolveValue(exe_ctx).IsValid()) {
if (error_ptr)
error_ptr->SetErrorString("Divide failed.");
diff --git a/lldb/test/Shell/SymbolFile/DWARF/x86/DW_OP_div-with-signed.s b/lldb/test/Shell/SymbolFile/DWARF/x86/DW_OP_div-with-signed.s
new file mode 100644
index 0000000000000..dd1a842864754
--- /dev/null
+++ b/lldb/test/Shell/SymbolFile/DWARF/x86/DW_OP_div-with-signed.s
@@ -0,0 +1,232 @@
+ # Test handling of values represented via DW_OP_div
+ # RUN: %clang -c --target=x86_64-pc-linux -o %t %s
+ # RUN: %lldb %t -o "expression -T -- g" -o "exit" | FileCheck %s
+
+ # Failing case was:
+ # (int) $0 = 0
+ # CHECK: (int) $0 = 2
+ #
+ # This file is crafted by hand on the basis of a very simple C program.
+
+ # The original (NOT THIS FILE) error-triggering code is:
+ # #include "stdint.h"
+ # static volatile uint64_t g = 0;
+ # static const int32_t f()
+ # {
+ # uint32_t i;
+ # for (i = 0; (i != 10); i++)
+ # ++g;
+ # return 0;
+ #
+ # }
+ #
+ # int main()
+ # {
+ # f();
+ # return 0;
+ #
+ # }
+ # When the above code is compiled by Clang 15.0.7 with -O1, it generates desired DW_OP_div for testing.
+ # Due to cross-platform issue, this case is hand-crafted for testing.
+
+ .text
+ .file "DW_OP_div-with-signed.c"
+ .file 0 "DW_OP_div-with-signed.c" # Dummy file
+ .globl main # -- Begin function main
+ .p2align 4, 0x90
+ .type main, at function
+main: # @main
+.Lfunc_begin0:
+ .loc 0 4 0 # DW_OP_div-with-signed.c:4:0
+ .cfi_startproc
+# %bb.0:
+ .loc 0 5 5 prologue_end # DW_OP_div-with-signed.c:5:5
+ xorl %eax, %eax
+ retq
+.Ltmp0:
+.Lfunc_end0:
+ .size main, .Lfunc_end0-main
+ .cfi_endproc
+ # -- End function
+ .type g, at object # @g
+ .data
+ .globl g
+ .p2align 2, 0x0
+g:
+ .long 3735928559 # 0xdeadbeef
+ .size g, 4
+
+ .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 37 # DW_FORM_strx1
+ .byte 19 # DW_AT_language
+ .byte 5 # DW_FORM_data2
+ .byte 3 # DW_AT_name
+ .byte 37 # DW_FORM_strx1
+ .byte 114 # DW_AT_str_offsets_base
+ .byte 23 # DW_FORM_sec_offset
+ .byte 16 # DW_AT_stmt_list
+ .byte 23 # DW_FORM_sec_offset
+ .byte 27 # DW_AT_comp_dir
+ .byte 37 # DW_FORM_strx1
+ .byte 17 # DW_AT_low_pc
+ .byte 27 # DW_FORM_addrx
+ .byte 18 # DW_AT_high_pc
+ .byte 6 # DW_FORM_data4
+ .byte 115 # DW_AT_addr_base
+ .byte 23 # DW_FORM_sec_offset
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+ .byte 2 # Abbreviation Code
+ .byte 52 # DW_TAG_variable
+ .byte 0 # DW_CHILDREN_no
+ .byte 3 # DW_AT_name
+ .byte 37 # DW_FORM_strx1
+ .byte 73 # DW_AT_type
+ .byte 19 # DW_FORM_ref4
+ .byte 63 # DW_AT_external
+ .byte 25 # DW_FORM_flag_present
+ .byte 58 # DW_AT_decl_file
+ .byte 11 # DW_FORM_data1
+ .byte 59 # DW_AT_decl_line
+ .byte 11 # DW_FORM_data1
+ .byte 2 # DW_AT_location
+ .byte 24 # DW_FORM_exprloc
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+ .byte 3 # Abbreviation Code
+ .byte 36 # DW_TAG_base_type
+ .byte 0 # DW_CHILDREN_no
+ .byte 3 # DW_AT_name
+ .byte 37 # DW_FORM_strx1
+ .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 4 # Abbreviation Code
+ .byte 46 # DW_TAG_subprogram
+ .byte 0 # DW_CHILDREN_no
+ .byte 17 # DW_AT_low_pc
+ .byte 27 # DW_FORM_addrx
+ .byte 18 # DW_AT_high_pc
+ .byte 6 # DW_FORM_data4
+ .byte 64 # DW_AT_frame_base
+ .byte 24 # DW_FORM_exprloc
+ .byte 122 # DW_AT_call_all_calls
+ .byte 25 # DW_FORM_flag_present
+ .byte 3 # DW_AT_name
+ .byte 37 # DW_FORM_strx1
+ .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 0 # EOM(3)
+ .section .debug_info,"", at progbits
+.Lcu_begin0:
+ .long .Ldebug_info_end0-.Ldebug_info_start0 # Length of Unit
+.Ldebug_info_start0:
+ .short 5 # DWARF version number
+ .byte 1 # DWARF Unit Type
+ .byte 8 # Address Size (in bytes)
+ .long .debug_abbrev # Offset Into Abbrev. Section
+ .byte 1 # Abbrev [1] 0xc:0x36 DW_TAG_compile_unit
+ .byte 0 # DW_AT_producer
+ .short 29 # DW_AT_language
+ .byte 1 # DW_AT_name
+ .long .Lstr_offsets_base0 # DW_AT_str_offsets_base
+ .long .Lline_table_start0 # DW_AT_stmt_list
+ .byte 2 # DW_AT_comp_dir
+ .byte 1 # DW_AT_low_pc
+ .long .Lfunc_end0-.Lfunc_begin0 # DW_AT_high_pc
+ .long .Laddr_table_base0 # DW_AT_addr_base
+ .byte 2 # Abbrev [2] 0x23:0xb DW_TAG_variable
+ .byte 3 # DW_AT_name
+ .long 60 # DW_AT_type
+ # DW_AT_external
+ .byte 0 # DW_AT_decl_file
+ .byte 1 # DW_AT_decl_line
+ .byte 16 # DW_AT_location
+ .byte 49
+ .byte 49
+ .byte 16 # DW_OP_constu
+ .byte 255 # 4294967295
+ .byte 255 #
+ .byte 255 #
+ .byte 255 #
+ .byte 15 #
+ .byte 26 # DW_OP_and
+ .byte 17 # DW_OP_consts
+ .byte 3 # 3
+ .byte 28 # DW_OP_minus
+ .byte 17 # DW_OP_consts
+ .byte 127 # -1
+ .byte 27 # DW_OP_div
+ .byte 159
+ .byte 3 # Abbrev [3] 0x2e:0x4 DW_TAG_base_type
+ .byte 4 # DW_AT_name
+ .byte 5 # DW_AT_encoding
+ .byte 4 # DW_AT_byte_size
+ .byte 4 # Abbrev [4] 0x32:0xf DW_TAG_subprogram
+ .byte 1 # DW_AT_low_pc
+ .long .Lfunc_end0-.Lfunc_begin0 # DW_AT_high_pc
+ .byte 1 # DW_AT_frame_base
+ .byte 87
+ # DW_AT_call_all_calls
+ .byte 5 # DW_AT_name
+ .byte 0 # DW_AT_decl_file
+ .byte 3 # DW_AT_decl_line
+ .long 60 # DW_AT_type
+ # DW_AT_external
+ .byte 0 # End Of Children Mark
+.Ldebug_info_end0:
+ .section .debug_str_offsets,"", at progbits
+ .long 28 # Length of String Offsets Set
+ .short 5
+ .short 0
+.Lstr_offsets_base0:
+ .section .debug_str,"MS", at progbits,1
+.Linfo_string0:
+ .asciz "clang version 17.0.0 (https://github.com/llvm/llvm-project.git 1b18ab358a8e91e69a54f676c77f6a4cda8ba02d)" # string offset=0
+.Linfo_string1:
+ .asciz "DW_OP_div-with-signed.c" # string offset=105
+.Linfo_string2:
+ .asciz "" # string offset=129
+.Linfo_string3:
+ .asciz "g" # string offset=166
+.Linfo_string4:
+ .asciz "int" # string offset=168
+.Linfo_string5:
+ .asciz "main" # string offset=172
+ .section .debug_str_offsets,"", at progbits
+ .long .Linfo_string0
+ .long .Linfo_string1
+ .long .Linfo_string2
+ .long .Linfo_string3
+ .long .Linfo_string4
+ .long .Linfo_string5
+ .section .debug_addr,"", at progbits
+ .long .Ldebug_addr_end0-.Ldebug_addr_start0 # Length of contribution
+.Ldebug_addr_start0:
+ .short 5 # DWARF version number
+ .byte 8 # Address size
+ .byte 0 # Segment selector size
+.Laddr_table_base0:
+ .quad g
+ .quad .Lfunc_begin0
+.Ldebug_addr_end0:
+ .ident "clang version 17.0.0 (https://github.com/llvm/llvm-project.git 1b18ab358a8e91e69a54f676c77f6a4cda8ba02d)"
+ .section ".note.GNU-stack","", at progbits
+ .addrsig
+ .section .debug_line,"", at progbits
+.Lline_table_start0:
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