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[lldb] Fix SLEB128 decoding

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Bug 46181 shows SLEB128 0xED9A924C00011151 decoded as 0xffffffff80011151.
        LLDB show a wrong value for function argument
        https://bugs.llvm.org/show_bug.cgi?id=46181

Differential Revision: https://reviews.llvm.org/D81119
This commit is contained in:
Jan Kratochvil 2020-06-04 19:41:24 +02:00
parent 7381fcdf62
commit 476f520a0b
3 changed files with 124 additions and 1 deletions
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2
lldb/source/Utility/DataExtractor.cpp
View File

@ -931,7 +931,7 @@ int64_t DataExtractor::GetSLEB128(offset_t *offset_ptr) const {
// Sign bit of byte is 2nd high order bit (0x40)
if (shift < size && (byte & 0x40))
result |= -(1 << shift);
result |= -(static_cast<int64_t>(1) << shift);
*offset_ptr += bytecount;
return result;

85
lldb/test/Shell/SymbolFile/DWARF/DW_TAG_variable-DW_AT_const_value.s Normal file
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@ -0,0 +1,85 @@
# This tests that lldb is able to print DW_TAG_variable using DW_AT_const_value.
# REQUIRES: x86
# RUN: llvm-mc -triple x86_64-unknown-linux-gnu %s -filetype=obj > %t.o
# RUN: %lldb %t.o -o "p/x magic64" -o exit | FileCheck %s
# CHECK: (const long) $0 = 0xed9a924c00011151
# The DW_TAG_variable using DW_AT_const_value. can be produced from:
# static const long magic64 = 0xed9a924c00011151;
# int main(void) { return magic64; }
.text
.globl main # -- Begin function main
.type main,@function
main: # @main
.Lfunc_end0:
.size main, .Lfunc_end0-main
# -- End function
.section .debug_abbrev,"",@progbits
.byte 1 # Abbreviation Code
.byte 17 # DW_TAG_compile_unit
.byte 1 # DW_CHILDREN_yes
.byte 37 # DW_AT_producer
.byte 8 # DW_FORM_string
.byte 19 # DW_AT_language
.byte 5 # DW_FORM_data2
.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 8 # DW_FORM_string
.byte 73 # DW_AT_type
.byte 19 # DW_FORM_ref4
.byte 28 # DW_AT_const_value
# .byte 15 # DW_FORM_udata
.byte 13 # DW_FORM_sdata
.byte 0 # EOM(1)
.byte 0 # EOM(2)
.byte 3 # 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 4 # Abbreviation Code
.byte 36 # DW_TAG_base_type
.byte 0 # DW_CHILDREN_no
.byte 3 # DW_AT_name
.byte 8 # DW_FORM_string
.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,"",@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:0x61 DW_TAG_compile_unit
.asciz "clang version 10.0.0" # DW_AT_producer
.short 12 # DW_AT_language
.byte 2 # Abbrev [2] 0x2a:0x15 DW_TAG_variable
.asciz "magic64" # DW_AT_name
.long .Lconst # DW_AT_type
.sleb128 0xed9a924c00011151 # DW_AT_const_value
.Lconst:
.byte 3 # Abbrev [3] 0x3f:0x5 DW_TAG_const_type
.long .Lint64 # DW_AT_type
.Lint64:
.byte 4 # Abbrev [4] 0x44:0x7 DW_TAG_base_type
.asciz "long int" # DW_AT_name
.byte 5 # DW_AT_encoding
.byte 8 # DW_AT_byte_size
.byte 0 # End Of Children Mark
.Ldebug_info_end0:

38
lldb/unittests/Utility/DataExtractorTest.cpp
View File

@ -261,3 +261,41 @@ TEST(DataExtractorTest, GetMaxU64_unchecked) {
EXPECT_EQ(0x0102030405060708U, BE.GetMaxU64_unchecked(&offset, 8));
EXPECT_EQ(8U, offset);
}
TEST(DataExtractorTest, GetSLEB128_bit63) {
uint8_t buffer[] = {0xff, 0x80, 0xff, 0x80, 0xff, 0x80, 0xff, 0x80, 0x7f};
DataExtractor LE(buffer, sizeof(buffer), lldb::eByteOrderLittle,
sizeof(void *));
DataExtractor BE(buffer, sizeof(buffer), lldb::eByteOrderBig, sizeof(void *));
lldb::offset_t offset;
int64_t expected =
0b1111111100000001111111000000011111110000000111111100000001111111;
offset = 0;
EXPECT_EQ(expected, LE.GetSLEB128(&offset));
EXPECT_EQ(9U, offset);
offset = 0;
EXPECT_EQ(expected, BE.GetSLEB128(&offset));
EXPECT_EQ(9U, offset);
}
TEST(DataExtractorTest, GetULEB128_bit63) {
uint8_t buffer[] = {0xff, 0x80, 0xff, 0x80, 0xff, 0x80, 0xff, 0x80, 0x7f};
DataExtractor LE(buffer, sizeof(buffer), lldb::eByteOrderLittle,
sizeof(void *));
DataExtractor BE(buffer, sizeof(buffer), lldb::eByteOrderBig, sizeof(void *));
lldb::offset_t offset;
uint64_t expected =
0b0111111100000001111111000000011111110000000111111100000001111111;
offset = 0;
EXPECT_EQ(expected, LE.GetULEB128(&offset));
EXPECT_EQ(9U, offset);
offset = 0;
EXPECT_EQ(expected, BE.GetULEB128(&offset));
EXPECT_EQ(9U, offset);
}