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[lldb][ELF] Read symbols from .gnu_debugdata sect.
Summary: If the .symtab section is stripped from the binary it might be that there's a .gnu_debugdata section which contains a smaller .symtab in order to provide enough information to create a backtrace with function names or to set and hit a breakpoint on a function name. This change looks for a .gnu_debugdata section in the ELF object file. The .gnu_debugdata section contains a xz-compressed ELF file with a .symtab section inside. Symbols from that compressed .symtab section are merged with the main object file's .dynsym symbols (if any). In addition we always load the .dynsym even if there's a .symtab section. For example, the Fedora and RHEL operating systems strip their binaries but keep a .gnu_debugdata section. While gdb already can read this section, LLDB until this patch couldn't. To test this patch on a Fedora or RHEL operating system, try to set a breakpoint on the "help" symbol in the "zip" binary. Before this patch, only GDB can set this breakpoint; now LLDB also can do so without installing extra debug symbols: lldb /usr/bin/zip -b -o "b help" -o "r" -o "bt" -- -h The above line runs LLDB in batch mode and on the "/usr/bin/zip -h" target: (lldb) target create "/usr/bin/zip" Current executable set to '/usr/bin/zip' (x86_64). (lldb) settings set -- target.run-args "-h" Before the program starts, we set a breakpoint on the "help" symbol: (lldb) b help Breakpoint 1: where = zip`help, address = 0x00000000004093b0 Once the program is run and has hit the breakpoint we ask for a backtrace: (lldb) r Process 10073 stopped * thread #1, name = 'zip', stop reason = breakpoint 1.1 frame #0: 0x00000000004093b0 zip`help zip`help: -> 0x4093b0 <+0>: pushq %r12 0x4093b2 <+2>: movq 0x2af5f(%rip), %rsi ; + 4056 0x4093b9 <+9>: movl $0x1, %edi 0x4093be <+14>: xorl %eax, %eax Process 10073 launched: '/usr/bin/zip' (x86_64) (lldb) bt * thread #1, name = 'zip', stop reason = breakpoint 1.1 * frame #0: 0x00000000004093b0 zip`help frame #1: 0x0000000000403970 zip`main + 3248 frame #2: 0x00007ffff7d8bf33 libc.so.6`__libc_start_main + 243 frame #3: 0x0000000000408cee zip`_start + 46 In order to support the .gnu_debugdata section, one has to have LZMA development headers installed. The CMake section, that controls this part looks for the LZMA headers and enables .gnu_debugdata support by default if they are found; otherwise or if explicitly requested, the minidebuginfo support is disabled. GDB supports the "mini debuginfo" section .gnu_debugdata since v7.6 (2013). Reviewers: espindola, labath, jankratochvil, alexshap Reviewed By: labath Subscribers: rnkovacs, wuzish, shafik, emaste, mgorny, arichardson, hiraditya, MaskRay, lldb-commits Tags: #lldb, #llvm Differential Revision: https://reviews.llvm.org/D66791 llvm-svn: 373891
1 parent 5ce8c39 commit 2c082b4

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-8
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‎lldb/cmake/modules/LLDBConfig.cmake‎

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include(CheckCXXSymbolExists)
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include(CheckTypeSize)
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include(CMakeDependentOption)
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set(LLDB_PROJECT_ROOT ${CMAKE_CURRENT_SOURCE_DIR})
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set(LLDB_SOURCE_ROOT "${CMAKE_CURRENT_SOURCE_DIR}/source")
@@ -384,6 +385,13 @@ endif()
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set(LLDB_VERSION "${LLDB_VERSION_MAJOR}.${LLDB_VERSION_MINOR}.${LLDB_VERSION_PATCH}${LLDB_VERSION_SUFFIX}")
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message(STATUS "LLDB version: ${LLDB_VERSION}")
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find_package(LibLZMA)
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cmake_dependent_option(LLDB_ENABLE_LZMA "Support LZMA compression" ON "LIBLZMA_FOUND" OFF)
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if (LLDB_ENABLE_LZMA)
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include_directories(${LIBLZMA_INCLUDE_DIRS})
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endif()
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llvm_canonicalize_cmake_booleans(LLDB_ENABLE_LZMA)
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include_directories(BEFORE
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${CMAKE_CURRENT_BINARY_DIR}/include
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${CMAKE_CURRENT_SOURCE_DIR}/include

‎lldb/include/lldb/Host/Config.h.cmake‎

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#cmakedefine HAVE_LIBCOMPRESSION
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#endif
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#cmakedefine01 LLDB_ENABLE_LZMA
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#endif // #ifndef LLDB_HOST_CONFIG_H

‎lldb/include/lldb/Host/LZMA.h‎

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//===-- LZMA.h --------------------------------------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef liblldb_Host_LZMA_h_
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#define liblldb_Host_LZMA_h_
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#include "llvm/ADT/ArrayRef.h"
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namespace llvm {
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class Error;
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} // End of namespace llvm
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namespace lldb_private {
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namespace lzma {
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bool isAvailable();
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llvm::Expected<uint64_t>
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getUncompressedSize(llvm::ArrayRef<uint8_t> InputBuffer);
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llvm::Error uncompress(llvm::ArrayRef<uint8_t> InputBuffer,
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llvm::SmallVectorImpl<uint8_t> &Uncompressed);
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} // End of namespace lzma
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} // End of namespace lldb_private
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#endif // liblldb_Host_LZMA_h_

‎lldb/lit/CMakeLists.txt‎

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lli
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llvm-config
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llvm-dwarfdump
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llvm-nm
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llvm-mc
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llvm-objcopy
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llvm-readobj
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llvm-strip
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)
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if(TARGET lld)

‎lldb/lit/Modules/ELF/Inputs/minidebuginfo-main.c‎

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// This function will be embedded within the .symtab section of the
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// .gnu_debugdata section.
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int multiplyByFour(int num) { return num * 4; }
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// This function will be embedded within the .dynsym section of the main binary.
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int multiplyByThree(int num) { return num * 3; }
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int main(int argc, char *argv[]) {
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int x = multiplyByThree(argc);
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int y = multiplyByFour(x);
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return y;
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}

‎lldb/lit/Modules/ELF/minidebuginfo-corrupt-xz.yaml‎

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# REQUIRES: lzma
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# This test checks that an error occurs when a corrupted
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# .gnu_debugdata section is trying to be xz uncompressed.
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# RUN: yaml2obj %s > %t.obj
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# TODO(kwk): once yaml2obj doesn't auto-generate a .symtab section
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# when there's none in YAML, remove the following line:
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# RUN: llvm-objcopy --remove-section=.symtab %t.obj
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# RUN: %lldb -b -o 'image dump symtab' %t.obj 2>&1 | FileCheck %s
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# CHECK: warning: (x86_64) {{.*}}.obj An error occurred while decompression the section .gnu_debugdata: lzma_stream_buffer_decode()=lzma error: LZMA_DATA_ERROR
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--- !ELF
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FileHeader:
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Class: ELFCLASS64
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Data: ELFDATA2LSB
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Type: ET_EXEC
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Machine: EM_X86_64
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Entry: 0x00000000004004C0
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Sections:
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- Name: .gnu_debugdata
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Type: SHT_PROGBITS
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AddressAlign: 0x0000000000000001
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Content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...

‎lldb/lit/Modules/ELF/minidebuginfo-find-symbols.yaml‎

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# REQUIRES: lzma
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# RUN: yaml2obj %s > %t.obj
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# TODO(kwk): once yaml2obj doesn't auto-generate a .symtab section
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# when there's none in YAML, remove the following line:
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# RUN: llvm-objcopy --remove-section=.symtab %t.obj
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# RUN: %lldb -b -o 'image dump symtab' %t.obj | FileCheck %s
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# CHECK: [ 0] 1 X Code 0x00000000004005b0 0x000000000000000f 0x00000012 multiplyByFour
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--- !ELF
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FileHeader:
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Class: ELFCLASS64
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Data: ELFDATA2LSB
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Type: ET_EXEC
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Machine: EM_X86_64
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Entry: 0x00000000004004C0
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Sections:
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- Name: .gnu_debugdata
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Type: SHT_PROGBITS
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AddressAlign: 0x0000000000000001
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Content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...

‎lldb/lit/Modules/ELF/minidebuginfo-no-lzma.yaml‎

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# REQUIRES: !lzma
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# This test checks that a warning is printed when we're trying
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# to decompress a .gnu_debugdata section when no LZMA support was compiled in.
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# RUN: yaml2obj %s > %t.obj
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# TODO(kwk): once yaml2obj doesn't auto-generate a .symtab section
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# when there's none in YAML, remove the following line:
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# RUN: llvm-objcopy --remove-section=.symtab %t.obj
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# RUN: %lldb -b -o 'image dump symtab' %t.obj 2>&1 | FileCheck %s
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# CHECK: warning: (x86_64) {{.*}}.obj No LZMA support found for reading .gnu_debugdata section
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--- !ELF
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FileHeader:
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Class: ELFCLASS64
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Data: ELFDATA2LSB
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Type: ET_EXEC
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Machine: EM_X86_64
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Entry: 0x00000000004004C0
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Sections:
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- Name: .gnu_debugdata
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Type: SHT_PROGBITS
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AddressAlign: 0x0000000000000001
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Content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...

‎lldb/lit/Modules/ELF/minidebuginfo-set-and-hit-breakpoint.test‎

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# REQUIRES: system-linux, lzma, xz
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# We want to keep the symbol "multiplyByThree" in the .dynamic section and not
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# have it put the default .symtab section.
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# RUN: echo "{multiplyByThree;};" > %T/dynmic-symbols.txt
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# RUN: %clang -Wl,--dynamic-list=%T/dynmic-symbols.txt -g -o %t.binary %p/Inputs/minidebuginfo-main.c
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# The following section is adapted from GDB's official documentation:
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# http://sourceware.org/gdb/current/onlinedocs/gdb/MiniDebugInfo.html#MiniDebugInfo
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# Extract the dynamic symbols from the main binary, there is no need
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# to also have these in the normal symbol table.
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# IGNORE: llvm-nm -D %t.binary --format=posix --defined-only | awk '{ print $1 }' | sort > %t.dynsyms
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# Extract all the text (i.e. function) symbols from the debuginfo.
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# (Note that we actually also accept "D" symbols, for the benefit
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# of platforms like PowerPC64 that use function descriptors.)
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# IGNORE: llvm-nm %t.binary --format=posix --defined-only | awk '{ if ($2 == "T" || $2 == "t" || $2 == "D") print $1 }' | sort > %t.funcsyms
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# Keep all the function symbols not already in the dynamic symbol
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# table.
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# IGNORE: comm -13 %t.dynsyms %t.funcsyms > %t.keep_symbols
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# The result of the preceeding command can be preprocessed in %p/Inputs/minidebuginfo.keep_symbols
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# because we know what symbol to keep.
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# RUN: echo "multiplyByFour" > %p/Inputs/minidebuginfo.keep_symbols
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# Separate full debug info into debug binary.
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# RUN: llvm-objcopy --only-keep-debug %t.binary %t.debug
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# Copy the full debuginfo, keeping only a minimal set of symbols and
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# removing some unnecessary sections.
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# RUN: llvm-objcopy -S --remove-section .gdb_index --remove-section .comment --keep-symbols=%p/Inputs/minidebuginfo.keep_symbols %t.debug %t.mini_debuginfo
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# This command is not from the GDB manual but it slims down embedded minidebug
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# info. On top if that, it ensures that we only have the multiplyByThree symbol
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# in the .dynsym section of the main binary.
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# RUN: llvm-objcopy --remove-section=.rela.dyn --remove-section=.gnu.version --remove-section=.gnu.hash --remove-section=.dynsym %t.mini_debuginfo
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# Drop the full debug info from the original binary.
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# RUN: llvm-strip --strip-all -R .comment %t.binary
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# Inject the compressed data into the .gnu_debugdata section of the
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# original binary.
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# RUN: xz --force --keep %t.mini_debuginfo
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# RUN: llvm-objcopy --add-section .gnu_debugdata=%t.mini_debuginfo.xz %t.binary
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# Now run the binary and see that we can set and hit a breakpoint
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# from within the .dynsym section (multiplyByThree) and one from
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# the .symtab section embedded in the .gnu_debugdata section (multiplyByFour).
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# RUN: %lldb -b -o 'b multiplyByThree' -o 'b multiplyByFour' -o 'run' -o 'continue' -o 'breakpoint list -v' %t.binary | FileCheck %s
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# CHECK: (lldb) b multiplyByThree
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# CHECK-NEXT: Breakpoint 1: where = minidebuginfo-set-and-hit-breakpoint.test.tmp.binary`multiplyByThree, address = 0x{{.*}}
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# CHECK: (lldb) b multiplyByFour
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# CHECK-NEXT: Breakpoint 2: where = minidebuginfo-set-and-hit-breakpoint.test.tmp.binary`multiplyByFour, address = 0x{{.*}}
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# CHECK: * thread #1, name = 'minidebuginfo-s', stop reason = breakpoint 1.1
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# CHECK: * thread #1, name = 'minidebuginfo-s', stop reason = breakpoint 2.1
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# CHECK: (lldb) breakpoint list -v
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# CHECK-NEXT: Current breakpoints:
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# CHECK-NEXT: 1: name = 'multiplyByThree'
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# CHECK-NEXT: 1.1:
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# CHECK-NEXT: module = {{.*}}/minidebuginfo-set-and-hit-breakpoint.test.tmp.binary
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# CHECK-NEXT: symbol = multiplyByThree
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# CHECK-NEXT: address = 0x{{.*}}
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# CHECK-NEXT: resolved = true
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# CHECK-NEXT: hit count = 1
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# CHECK: 2: name = 'multiplyByFour'
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# CHECK-NEXT: 2.1:
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# CHECK-NEXT: module = {{.*}}/minidebuginfo-set-and-hit-breakpoint.test.tmp.binary
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# CHECK-NEXT: symbol = multiplyByFour
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# CHECK-NEXT: address = 0x{{.*}}
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# CHECK-NEXT: resolved = true
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# CHECK-NEXT: hit count = 1

‎lldb/lit/lit.cfg.py‎

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Original file line numberDiff line numberDiff line change
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from lit.llvm import llvm_config
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from lit.llvm.subst import FindTool
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from lit.llvm.subst import ToolSubst
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from distutils.spawn import find_executable
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site.addsitedir(os.path.dirname(__file__))
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from helper import toolchain
@@ -98,3 +99,9 @@ def calculate_arch_features(arch_string):
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if not config.lldb_disable_python:
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config.available_features.add('python')
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if config.lldb_enable_lzma:
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config.available_features.add('lzma')
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if find_executable('xz') != None:
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config.available_features.add('xz')

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