llvm-project/lldb/test/Shell/lit.cfg.py

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# -*- Python -*-
import os
import platform
import re
import shutil
Fix some issues with LLDB's lit configuration files. Recently I tried to port LLDB's lit configuration files over to use a on the surface, but broke some cases that weren't broken before and also exposed some additional problems with the old approach that we were just getting lucky with. When we set up a lit environment, the goal is to make it as hermetic as possible. We should not be relying on PATH and enabling the use of arbitrary shell commands. Instead, only whitelisted commands should be allowed. These are, generally speaking, the lit builtins such as echo, cd, etc, as well as anything for which substitutions have been explicitly set up for. These substitutions should map to the build output directory, but in some cases it's useful to be able to override this (for example to point to an installed tools directory). This is, of course, how it's supposed to work. What was actually happening is that we were bringing in PATH and LD_LIBRARY_PATH and then just running the given run line as a shell command. This led to problems such as finding the wrong version of clang-cl on PATH since it wasn't even a substitution, and flakiness / non-determinism since the environment the tests were running in would change per-machine. On the other hand, it also made other things possible. For example, we had some tests that were explicitly running cl.exe and link.exe instead of clang-cl and lld-link and the only reason it worked at all is because it was finding them on PATH. Unfortunately we can't entirely get rid of these tests, because they support a few things in debug info that clang-cl and lld-link don't (notably, the LF_UDT_MOD_SRC_LINE record which makes some of the tests fail. The high level changes introduced in this patch are: 1. Removal of functionality - The lit test suite no longer respects LLDB_TEST_C_COMPILER and LLDB_TEST_CXX_COMPILER. This means there is no more support for gcc, but nobody was using this anyway (note: The functionality is still there for the dotest suite, just not the lit test suite). There is no longer a single substitution %cxx and %cc which maps to <arbitrary-compiler>, you now explicitly specify the compiler with a substitution like %clang or %clangxx or %clang_cl. We can revisit this in the future when someone needs gcc. 2. Introduction of the LLDB_LIT_TOOLS_DIR directory. This does in spirit what LLDB_TEST_C_COMPILER and LLDB_TEST_CXX_COMPILER used to do, but now more friendly. If this is not specified, all tools are expected to be the just-built tools. If it is specified, the tools which are not themselves being tested but are being used to construct and run checks (e.g. clang, FileCheck, llvm-mc, etc) will be searched for in this directory first, then the build output directory. 3. Changes to core llvm lit files. The use_lld() and use_clang() functions were introduced long ago in anticipation of using them in lldb, but since they were never actually used anywhere but their respective problems, there were some issues to be resolved regarding generality and ability to use them outside their project. 4. Changes to .test files - These are all just replacing things like clang-cl with %clang_cl and %cxx with %clangxx, etc. 5. Changes to lit.cfg.py - Previously we would load up some system environment variables and then add some new things to them. Then do a bunch of work building out our own substitutions. First, we delete the system environment variable code, making the environment hermetic. Then, we refactor the substitution logic into two separate helper functions, one which sets up substitutions for the tools we want to test (which must come from the build output directory), and another which sets up substitutions for support tools (like compilers, etc). 6. New substitutions for MSVC -- Previously we relied on location of MSVC by bringing in the entire parent's PATH and letting subprocess.Popen just run the command line. Now we set up real substitutions that should have the same effect. We use PATH to find them, and then look for INCLUDE and LIB to construct a substitution command line with appropriate /I and /LIBPATH: arguments. The nice thing about this is that it opens the door to having separate %msvc-cl32 and %msvc-cl64 substitutions, rather than only requiring the user to run vcvars first. Because we can deduce the path to 32-bit libraries from 64-bit library directories, and vice versa. Without these substitutions this would have been impossible. Differential Revision: https://reviews.llvm.org/D54567 llvm-svn: 347216
2018-11-19 23:12:34 +08:00
import site
import subprocess
Fix some issues with LLDB's lit configuration files. Recently I tried to port LLDB's lit configuration files over to use a on the surface, but broke some cases that weren't broken before and also exposed some additional problems with the old approach that we were just getting lucky with. When we set up a lit environment, the goal is to make it as hermetic as possible. We should not be relying on PATH and enabling the use of arbitrary shell commands. Instead, only whitelisted commands should be allowed. These are, generally speaking, the lit builtins such as echo, cd, etc, as well as anything for which substitutions have been explicitly set up for. These substitutions should map to the build output directory, but in some cases it's useful to be able to override this (for example to point to an installed tools directory). This is, of course, how it's supposed to work. What was actually happening is that we were bringing in PATH and LD_LIBRARY_PATH and then just running the given run line as a shell command. This led to problems such as finding the wrong version of clang-cl on PATH since it wasn't even a substitution, and flakiness / non-determinism since the environment the tests were running in would change per-machine. On the other hand, it also made other things possible. For example, we had some tests that were explicitly running cl.exe and link.exe instead of clang-cl and lld-link and the only reason it worked at all is because it was finding them on PATH. Unfortunately we can't entirely get rid of these tests, because they support a few things in debug info that clang-cl and lld-link don't (notably, the LF_UDT_MOD_SRC_LINE record which makes some of the tests fail. The high level changes introduced in this patch are: 1. Removal of functionality - The lit test suite no longer respects LLDB_TEST_C_COMPILER and LLDB_TEST_CXX_COMPILER. This means there is no more support for gcc, but nobody was using this anyway (note: The functionality is still there for the dotest suite, just not the lit test suite). There is no longer a single substitution %cxx and %cc which maps to <arbitrary-compiler>, you now explicitly specify the compiler with a substitution like %clang or %clangxx or %clang_cl. We can revisit this in the future when someone needs gcc. 2. Introduction of the LLDB_LIT_TOOLS_DIR directory. This does in spirit what LLDB_TEST_C_COMPILER and LLDB_TEST_CXX_COMPILER used to do, but now more friendly. If this is not specified, all tools are expected to be the just-built tools. If it is specified, the tools which are not themselves being tested but are being used to construct and run checks (e.g. clang, FileCheck, llvm-mc, etc) will be searched for in this directory first, then the build output directory. 3. Changes to core llvm lit files. The use_lld() and use_clang() functions were introduced long ago in anticipation of using them in lldb, but since they were never actually used anywhere but their respective problems, there were some issues to be resolved regarding generality and ability to use them outside their project. 4. Changes to .test files - These are all just replacing things like clang-cl with %clang_cl and %cxx with %clangxx, etc. 5. Changes to lit.cfg.py - Previously we would load up some system environment variables and then add some new things to them. Then do a bunch of work building out our own substitutions. First, we delete the system environment variable code, making the environment hermetic. Then, we refactor the substitution logic into two separate helper functions, one which sets up substitutions for the tools we want to test (which must come from the build output directory), and another which sets up substitutions for support tools (like compilers, etc). 6. New substitutions for MSVC -- Previously we relied on location of MSVC by bringing in the entire parent's PATH and letting subprocess.Popen just run the command line. Now we set up real substitutions that should have the same effect. We use PATH to find them, and then look for INCLUDE and LIB to construct a substitution command line with appropriate /I and /LIBPATH: arguments. The nice thing about this is that it opens the door to having separate %msvc-cl32 and %msvc-cl64 substitutions, rather than only requiring the user to run vcvars first. Because we can deduce the path to 32-bit libraries from 64-bit library directories, and vice versa. Without these substitutions this would have been impossible. Differential Revision: https://reviews.llvm.org/D54567 llvm-svn: 347216
2018-11-19 23:12:34 +08:00
import sys
import lit.formats
from lit.llvm import llvm_config
from lit.llvm.subst import FindTool
from lit.llvm.subst import ToolSubst
site.addsitedir(os.path.dirname(__file__))
Fix some issues with LLDB's lit configuration files. Recently I tried to port LLDB's lit configuration files over to use a on the surface, but broke some cases that weren't broken before and also exposed some additional problems with the old approach that we were just getting lucky with. When we set up a lit environment, the goal is to make it as hermetic as possible. We should not be relying on PATH and enabling the use of arbitrary shell commands. Instead, only whitelisted commands should be allowed. These are, generally speaking, the lit builtins such as echo, cd, etc, as well as anything for which substitutions have been explicitly set up for. These substitutions should map to the build output directory, but in some cases it's useful to be able to override this (for example to point to an installed tools directory). This is, of course, how it's supposed to work. What was actually happening is that we were bringing in PATH and LD_LIBRARY_PATH and then just running the given run line as a shell command. This led to problems such as finding the wrong version of clang-cl on PATH since it wasn't even a substitution, and flakiness / non-determinism since the environment the tests were running in would change per-machine. On the other hand, it also made other things possible. For example, we had some tests that were explicitly running cl.exe and link.exe instead of clang-cl and lld-link and the only reason it worked at all is because it was finding them on PATH. Unfortunately we can't entirely get rid of these tests, because they support a few things in debug info that clang-cl and lld-link don't (notably, the LF_UDT_MOD_SRC_LINE record which makes some of the tests fail. The high level changes introduced in this patch are: 1. Removal of functionality - The lit test suite no longer respects LLDB_TEST_C_COMPILER and LLDB_TEST_CXX_COMPILER. This means there is no more support for gcc, but nobody was using this anyway (note: The functionality is still there for the dotest suite, just not the lit test suite). There is no longer a single substitution %cxx and %cc which maps to <arbitrary-compiler>, you now explicitly specify the compiler with a substitution like %clang or %clangxx or %clang_cl. We can revisit this in the future when someone needs gcc. 2. Introduction of the LLDB_LIT_TOOLS_DIR directory. This does in spirit what LLDB_TEST_C_COMPILER and LLDB_TEST_CXX_COMPILER used to do, but now more friendly. If this is not specified, all tools are expected to be the just-built tools. If it is specified, the tools which are not themselves being tested but are being used to construct and run checks (e.g. clang, FileCheck, llvm-mc, etc) will be searched for in this directory first, then the build output directory. 3. Changes to core llvm lit files. The use_lld() and use_clang() functions were introduced long ago in anticipation of using them in lldb, but since they were never actually used anywhere but their respective problems, there were some issues to be resolved regarding generality and ability to use them outside their project. 4. Changes to .test files - These are all just replacing things like clang-cl with %clang_cl and %cxx with %clangxx, etc. 5. Changes to lit.cfg.py - Previously we would load up some system environment variables and then add some new things to them. Then do a bunch of work building out our own substitutions. First, we delete the system environment variable code, making the environment hermetic. Then, we refactor the substitution logic into two separate helper functions, one which sets up substitutions for the tools we want to test (which must come from the build output directory), and another which sets up substitutions for support tools (like compilers, etc). 6. New substitutions for MSVC -- Previously we relied on location of MSVC by bringing in the entire parent's PATH and letting subprocess.Popen just run the command line. Now we set up real substitutions that should have the same effect. We use PATH to find them, and then look for INCLUDE and LIB to construct a substitution command line with appropriate /I and /LIBPATH: arguments. The nice thing about this is that it opens the door to having separate %msvc-cl32 and %msvc-cl64 substitutions, rather than only requiring the user to run vcvars first. Because we can deduce the path to 32-bit libraries from 64-bit library directories, and vice versa. Without these substitutions this would have been impossible. Differential Revision: https://reviews.llvm.org/D54567 llvm-svn: 347216
2018-11-19 23:12:34 +08:00
from helper import toolchain
# name: The name of this test suite.
config.name = 'lldb-shell'
# testFormat: The test format to use to interpret tests.
config.test_format = lit.formats.ShTest(not llvm_config.use_lit_shell)
# suffixes: A list of file extensions to treat as test files. This is overriden
# by individual lit.local.cfg files in the test subdirectories.
config.suffixes = ['.test', '.cpp', '.s']
# excludes: A list of directories to exclude from the testsuite. The 'Inputs'
# subdirectories contain auxiliary inputs for various tests in their parent
# directories.
config.excludes = ['Inputs', 'CMakeLists.txt', 'README.txt', 'LICENSE.txt']
# test_source_root: The root path where tests are located.
config.test_source_root = os.path.dirname(__file__)
# test_exec_root: The root path where tests should be run.
config.test_exec_root = os.path.join(config.lldb_obj_root, 'test', 'Shell')
# Propagate environment vars.
llvm_config.with_system_environment([
'FREEBSD_LEGACY_PLUGIN',
'HOME',
'TEMP',
'TMP',
'XDG_CACHE_HOME',
])
# Support running the test suite under the lldb-repro wrapper. This makes it
# possible to capture a test suite run and then rerun all the test from the
# just captured reproducer.
lldb_repro_mode = lit_config.params.get('lldb-run-with-repro', None)
if lldb_repro_mode:
config.available_features.add('lldb-repro')
lit_config.note("Running Shell tests in {} mode.".format(lldb_repro_mode))
toolchain.use_lldb_repro_substitutions(config, lldb_repro_mode)
Fix some issues with LLDB's lit configuration files. Recently I tried to port LLDB's lit configuration files over to use a on the surface, but broke some cases that weren't broken before and also exposed some additional problems with the old approach that we were just getting lucky with. When we set up a lit environment, the goal is to make it as hermetic as possible. We should not be relying on PATH and enabling the use of arbitrary shell commands. Instead, only whitelisted commands should be allowed. These are, generally speaking, the lit builtins such as echo, cd, etc, as well as anything for which substitutions have been explicitly set up for. These substitutions should map to the build output directory, but in some cases it's useful to be able to override this (for example to point to an installed tools directory). This is, of course, how it's supposed to work. What was actually happening is that we were bringing in PATH and LD_LIBRARY_PATH and then just running the given run line as a shell command. This led to problems such as finding the wrong version of clang-cl on PATH since it wasn't even a substitution, and flakiness / non-determinism since the environment the tests were running in would change per-machine. On the other hand, it also made other things possible. For example, we had some tests that were explicitly running cl.exe and link.exe instead of clang-cl and lld-link and the only reason it worked at all is because it was finding them on PATH. Unfortunately we can't entirely get rid of these tests, because they support a few things in debug info that clang-cl and lld-link don't (notably, the LF_UDT_MOD_SRC_LINE record which makes some of the tests fail. The high level changes introduced in this patch are: 1. Removal of functionality - The lit test suite no longer respects LLDB_TEST_C_COMPILER and LLDB_TEST_CXX_COMPILER. This means there is no more support for gcc, but nobody was using this anyway (note: The functionality is still there for the dotest suite, just not the lit test suite). There is no longer a single substitution %cxx and %cc which maps to <arbitrary-compiler>, you now explicitly specify the compiler with a substitution like %clang or %clangxx or %clang_cl. We can revisit this in the future when someone needs gcc. 2. Introduction of the LLDB_LIT_TOOLS_DIR directory. This does in spirit what LLDB_TEST_C_COMPILER and LLDB_TEST_CXX_COMPILER used to do, but now more friendly. If this is not specified, all tools are expected to be the just-built tools. If it is specified, the tools which are not themselves being tested but are being used to construct and run checks (e.g. clang, FileCheck, llvm-mc, etc) will be searched for in this directory first, then the build output directory. 3. Changes to core llvm lit files. The use_lld() and use_clang() functions were introduced long ago in anticipation of using them in lldb, but since they were never actually used anywhere but their respective problems, there were some issues to be resolved regarding generality and ability to use them outside their project. 4. Changes to .test files - These are all just replacing things like clang-cl with %clang_cl and %cxx with %clangxx, etc. 5. Changes to lit.cfg.py - Previously we would load up some system environment variables and then add some new things to them. Then do a bunch of work building out our own substitutions. First, we delete the system environment variable code, making the environment hermetic. Then, we refactor the substitution logic into two separate helper functions, one which sets up substitutions for the tools we want to test (which must come from the build output directory), and another which sets up substitutions for support tools (like compilers, etc). 6. New substitutions for MSVC -- Previously we relied on location of MSVC by bringing in the entire parent's PATH and letting subprocess.Popen just run the command line. Now we set up real substitutions that should have the same effect. We use PATH to find them, and then look for INCLUDE and LIB to construct a substitution command line with appropriate /I and /LIBPATH: arguments. The nice thing about this is that it opens the door to having separate %msvc-cl32 and %msvc-cl64 substitutions, rather than only requiring the user to run vcvars first. Because we can deduce the path to 32-bit libraries from 64-bit library directories, and vice versa. Without these substitutions this would have been impossible. Differential Revision: https://reviews.llvm.org/D54567 llvm-svn: 347216
2018-11-19 23:12:34 +08:00
llvm_config.use_default_substitutions()
toolchain.use_lldb_substitutions(config)
toolchain.use_support_substitutions(config)
if re.match(r'^arm(hf.*-linux)|(.*-linux-gnuabihf)', config.target_triple):
config.available_features.add("armhf-linux")
if re.match(r'.*-(windows-msvc)$', config.target_triple):
config.available_features.add("windows-msvc")
if re.match(r'.*-(windows-gnu|mingw32)$', config.target_triple):
config.available_features.add("windows-gnu")
def calculate_arch_features(arch_string):
# This will add a feature such as x86, arm, mips, etc for each built
# target
features = []
for arch in arch_string.split():
features.append(arch.lower())
return features
# Run llvm-config and add automatically add features for whether we have
# assertions enabled, whether we are in debug mode, and what targets we
# are built for.
llvm_config.feature_config(
[('--assertion-mode', {'ON': 'asserts'}),
('--build-mode', {'DEBUG': 'debug'}),
('--targets-built', calculate_arch_features)
])
# Clean the module caches in the test build directory. This is necessary in an
# incremental build whenever clang changes underneath, so doing it once per
# lit.py invocation is close enough.
for cachedir in [config.clang_module_cache, config.lldb_module_cache]:
if os.path.isdir(cachedir):
lit_config.note("Deleting module cache at %s."%cachedir)
shutil.rmtree(cachedir)
# Set a default per-test timeout of 10 minutes. Setting a timeout per test
# requires that killProcessAndChildren() is supported on the platform and
# lit complains if the value is set but it is not supported.
supported, errormsg = lit_config.maxIndividualTestTimeIsSupported
if supported:
lit_config.maxIndividualTestTime = 600
else:
lit_config.warning("Could not set a default per-test timeout. " + errormsg)
# If running tests natively, check for CPU features needed for some tests.
if 'native' in config.available_features:
cpuid_exe = lit.util.which('lit-cpuid', config.lldb_tools_dir)
if cpuid_exe is None:
lit_config.warning("lit-cpuid not found, tests requiring CPU extensions will be skipped")
else:
out, err, exitcode = lit.util.executeCommand([cpuid_exe])
if exitcode == 0:
for x in out.split():
config.available_features.add('native-cpu-%s' % x)
else:
lit_config.warning("lit-cpuid failed: %s" % err)
if config.lldb_enable_python:
config.available_features.add('python')
[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
2019-10-07 18:32:16 +08:00
if config.lldb_enable_lua:
config.available_features.add('lua')
[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
2019-10-07 18:32:16 +08:00
if config.lldb_enable_lzma:
config.available_features.add('lzma')
if shutil.which('xz') != None:
[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
2019-10-07 18:32:16 +08:00
config.available_features.add('xz')
if config.lldb_system_debugserver:
config.available_features.add('system-debugserver')
# NetBSD permits setting dbregs either if one is root
# or if user_set_dbregs is enabled
can_set_dbregs = True
if platform.system() == 'NetBSD' and os.geteuid() != 0:
try:
output = subprocess.check_output(["/sbin/sysctl", "-n",
"security.models.extensions.user_set_dbregs"]).decode().strip()
if output != "1":
can_set_dbregs = False
except subprocess.CalledProcessError:
can_set_dbregs = False
if can_set_dbregs:
config.available_features.add('dbregs-set')
if 'LD_PRELOAD' in os.environ:
config.available_features.add('ld_preload-present')