Commit Graph

17 Commits

Author SHA1 Message Date
Greg Clayton da816ca0cb Added the ability to cache the finalized symbol tables subsequent debug sessions to start faster.
This is an updated version of the https://reviews.llvm.org/D113789 patch with the following changes:
- We no longer modify modification times of the cache files
- Use LLVM caching and cache pruning instead of making a new cache mechanism (See DataFileCache.h/.cpp)
- Add signature to start of each file since we are not using modification times so we can tell when caches are stale and remove and re-create the cache file as files are changed
- Add settings to control the cache size, disk percentage and expiration in days to keep cache size under control

This patch enables symbol tables to be cached in the LLDB index cache directory. All cache files are in a single directory and the files use unique names to ensure that files from the same path will re-use the same file as files get modified. This means as files change, their cache files will be deleted and updated. The modification time of each of the cache files is not modified so that access based pruning of the cache can be implemented.

The symbol table cache files start with a signature that uniquely identifies a file on disk and contains one or more of the following items:
- object file UUID if available
- object file mod time if available
- object name for BSD archive .o files that are in .a files if available

If none of these signature items are available, then the file will not be cached. This keeps temporary object files from expressions from being cached.

When the cache files are loaded on subsequent debug sessions, the signature is compare and if the file has been modified (uuid changes, mod time changes, or object file mod time changes) then the cache file is deleted and re-created.

Module caching must be enabled by the user before this can be used:

symbols.enable-lldb-index-cache (boolean) = false

(lldb) settings set symbols.enable-lldb-index-cache true

There is also a setting that allows the user to specify a module cache directory that defaults to a directory that defaults to being next to the symbols.clang-modules-cache-path directory in a temp directory:

(lldb) settings show symbols.lldb-index-cache-path
/var/folders/9p/472sr0c55l9b20x2zg36b91h0000gn/C/lldb/IndexCache

If this setting is enabled, the finalized symbol tables will be serialized and saved to disc so they can be quickly loaded next time you debug.

Each module can cache one or more files in the index cache directory. The cache file names must be unique to a file on disk and its architecture and object name for .o files in BSD archives. This allows universal mach-o files to support caching multuple architectures in the same module cache directory. Making the file based on the this info allows this cache file to be deleted and replaced when the file gets updated on disk. This keeps the cache from growing over time during the compile/edit/debug cycle and prevents out of space issues.

If the cache is enabled, the symbol table will be loaded from the cache the next time you debug if the module has not changed.

The cache also has settings to control the size of the cache on disk. Each time LLDB starts up with the index cache enable, the cache will be pruned to ensure it stays within the user defined settings:

(lldb) settings set symbols.lldb-index-cache-expiration-days <days>

A value of zero will disable cache files from expiring when the cache is pruned. The default value is 7 currently.

(lldb) settings set symbols.lldb-index-cache-max-byte-size <size>

A value of zero will disable pruning based on a total byte size. The default value is zero currently.
(lldb) settings set symbols.lldb-index-cache-max-percent <percentage-of-disk-space>

A value of 100 will allow the disc to be filled to the max, a value of zero will disable percentage pruning. The default value is zero.

Reviewed By: labath, wallace

Differential Revision: https://reviews.llvm.org/D115324
2021-12-16 09:59:55 -08:00
Greg Clayton 244258e35a Modify DataEncoder to be able to encode data in an object owned buffer.
DataEncoder was previously made to modify data within an existing buffer. As the code progressed, new clients started using DataEncoder to create binary data. In these cases the use of this class was possibly, but only if you knew exactly how large your buffer would be ahead of time. This patchs adds the ability for DataEncoder to own a buffer that can be dynamically resized as data is appended to the buffer.

Change in this patch:
- Allow a DataEncoder object to be created that owns a DataBufferHeap object that can dynamically grow as data is appended
- Add new methods that start with "Append" to append data to the buffer and grow it as needed
- Adds full testing of the API to assure modifications don't regress any functionality
- Has two constructors: one that uses caller owned data and one that creates an object with object owned data
- "Append" methods only work if the object owns it own data
- Removes the ability to specify a shared memory buffer as no one was using this functionality. This allows us to switch to a case where the object owns its own data in a DataBufferHeap that can be resized as data is added

"Put" methods work on both caller and object owned data.
"Append" methods work on only object owned data where we can grow the buffer. These methods will return false if called on a DataEncoder object that has caller owned data.

The main reason for these modifications is to be able to use the DateEncoder objects instead of llvm::gsym::FileWriter in https://reviews.llvm.org/D113789. This patch wants to add the ability to create symbol table caching to LLDB and the code needs to build binary caches and save them to disk.

Reviewed By: labath

Differential Revision: https://reviews.llvm.org/D115073
2021-12-07 09:44:57 -08:00
Jonas Devlieghere 9494c510af [lldb] Use C++11 default member initializers
This converts a default constructor's member initializers into C++11
default member initializers. This patch was automatically generated with
clang-tidy and the modernize-use-default-member-init check.

$ run-clang-tidy.py -header-filter='lldb' -checks='-*,modernize-use-default-member-init' -fix

This is a mass-refactoring patch and this commit will be added to
.git-blame-ignore-revs.

Differential revision: https://reviews.llvm.org/D103483
2021-06-09 09:43:13 -07:00
Raphael Isemann 76e47d4887 [lldb][NFC] Use C++ versions of the deprecated C standard library headers
The C headers are deprecated so as requested in D102845, this is replacing them
all with their (not deprecated) C++ equivalent.

Reviewed By: shafik

Differential Revision: https://reviews.llvm.org/D103084
2021-05-26 12:46:12 +02:00
Raphael Isemann 808142876c [lldb][NFC] Fix all formatting errors in .cpp file headers
Summary:
A *.cpp file header in LLDB (and in LLDB) should like this:
```
//===-- TestUtilities.cpp -------------------------------------------------===//
```
However in LLDB most of our source files have arbitrary changes to this format and
these changes are spreading through LLDB as folks usually just use the existing
source files as templates for their new files (most notably the unnecessary
editor language indicator `-*- C++ -*-` is spreading and in every review
someone is pointing out that this is wrong, resulting in people pointing out that this
is done in the same way in other files).

This patch removes most of these inconsistencies including the editor language indicators,
all the different missing/additional '-' characters, files that center the file name, missing
trailing `===//` (mostly caused by clang-format breaking the line).

Reviewers: aprantl, espindola, jfb, shafik, JDevlieghere

Reviewed By: JDevlieghere

Subscribers: dexonsmith, wuzish, emaste, sdardis, nemanjai, kbarton, MaskRay, atanasyan, arphaman, jfb, abidh, jsji, JDevlieghere, usaxena95, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D73258
2020-01-24 08:52:55 +01:00
Raphael Isemann 3ca771ba59 [lldb][NFC] Remove unused includes in Utility's source files 2019-12-13 12:33:47 +01:00
Jonas Devlieghere 8ac053eea2 [LLDB] Cleanup the DataEncoder utility. (NFC)
This commit removes unused methods from the DataEncoder class and cleans
up the API by making all the internal methods private.
2019-11-13 15:44:51 -08:00
Jonas Devlieghere 24374aef1b [Utility] Modernize C-style cats
Replaces the remaining C-style casts with explicit casts in Utility. The
motivation is that they are (1) easier to spot and (2) don't have
multiple meanings.

llvm-svn: 361458
2019-05-23 05:12:11 +00:00
Jonas Devlieghere 8b3af63b89 [NFC] Remove ASCII lines from comments
A lot of comments in LLDB are surrounded by an ASCII line to delimit the
begging and end of the comment.

Its use is not really consistent across the code base, sometimes the
lines are longer, sometimes they are shorter and sometimes they are
omitted. Furthermore, it looks kind of weird with the 80 column limit,
where the comment actually extends past the line, but not by much.
Furthermore, when /// is used for Doxygen comments, it looks
particularly odd. And when // is used, it incorrectly gives the
impression that it's actually a Doxygen comment.

I assume these lines were added to improve distinguishing between
comments and code. However, given that todays editors and IDEs do a
great job at highlighting comments, I think it's worth to drop this for
the sake of consistency. The alternative is fixing all the
inconsistencies, which would create a lot more churn.

Differential revision: https://reviews.llvm.org/D60508

llvm-svn: 358135
2019-04-10 20:48:55 +00:00
Chandler Carruth 2946cd7010 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00
Jonas Devlieghere 672d2c1255 Remove comments after header includes.
This patch removes the comments following the header includes. They were
added after running IWYU over the LLDB codebase. However they add little
value, are often outdates and burdensome to maintain.

Differential revision: https://reviews.llvm.org/D54385

llvm-svn: 346625
2018-11-11 23:16:43 +00:00
Adrian Prantl 05097246f3 Reflow paragraphs in comments.
This is intended as a clean up after the big clang-format commit
(r280751), which unfortunately resulted in many of the comment
paragraphs in LLDB being very hard to read.

FYI, the script I used was:

import textwrap
import commands
import os
import sys
import re
tmp = "%s.tmp"%sys.argv[1]
out = open(tmp, "w+")
with open(sys.argv[1], "r") as f:
  header = ""
  text = ""
  comment = re.compile(r'^( *//) ([^ ].*)$')
  special = re.compile(r'^((([A-Z]+[: ])|([0-9]+ )).*)|(.*;)$')
  for line in f:
      match = comment.match(line)
      if match and not special.match(match.group(2)):
          # skip intentionally short comments.
          if not text and len(match.group(2)) < 40:
              out.write(line)
              continue

          if text:
              text += " " + match.group(2)
          else:
              header = match.group(1)
              text = match.group(2)

          continue

      if text:
          filled = textwrap.wrap(text, width=(78-len(header)),
                                 break_long_words=False)
          for l in filled:
              out.write(header+" "+l+'\n')
              text = ""

      out.write(line)

os.rename(tmp, sys.argv[1])

Differential Revision: https://reviews.llvm.org/D46144

llvm-svn: 331197
2018-04-30 16:49:04 +00:00
Davide Italiano 64c2760ecb [DataEncoder] Replace buggy versions of write functions.
This fixes a previously introduced thinko, now that I have
a better idea of what's going on :)

<rdar://problem/35941757>

llvm-svn: 320540
2017-12-13 01:41:16 +00:00
Davide Italiano 226aab7cdb Revert "[DataEncoder] Replace buggy versions of write functions."
The commit exposes a bunch of failures in the LLDB testsuite that
I need to analyze more carefully. Reverting for now.

llvm-svn: 320341
2017-12-11 05:09:35 +00:00
Davide Italiano d752d6b4be [DataEncoder] Replace buggy versions of write functions.
They cause an ubsan error when ran through the testsuite (store
to misaligned address is UB). This commit kills two birds with
one stone, as we also remove some code while fixing it.

<rdar://problem/35941757>

llvm-svn: 320335
2017-12-10 22:54:07 +00:00
Zachary Turner 4479ac15c9 iwyu fixes on lldbUtility.
This patch makes adjustments to header file includes in
lldbUtility based on recommendations by the iwyu tool
(include-what-you-use).  The goal here is to make sure that
all files include the exact set of headers which are needed
for that file only, to eliminate cases of dead includes (e.g.
someone deleted some code but forgot to delete the header
includes that that code necessitated), and to eliminate the
case where header includes are picked up transitively.

llvm-svn: 299676
2017-04-06 18:12:24 +00:00
Zachary Turner 666cc0b291 Move DataBuffer / DataExtractor and friends from Core -> Utility.
llvm-svn: 296943
2017-03-04 01:30:05 +00:00