Commit Graph

6370 Commits

Author SHA1 Message Date
Jonas Devlieghere f38234ed8b [lldb/CMake] Fix variable naming in FindLibEdit
The current FOUND_VAR for FindLibEdit is libedit_FOUND but wasn't set by
find_package_handle_standard_args. However this isn't valid for the
package name.

  The argument for FOUND_VAR is "libedit_FOUND", but only "LibEdit_FOUND" and
  "LIBEDIT_FOUND" are valid names.

This fixes all the variables set by FindLibEdit to match the desired
naming scheme.
2020-01-02 13:39:57 -08:00
Jonas Devlieghere 3ddfb04f41 [lldb/CMake] Use PYTHON_LIBRARIES instead of PYTHON_LIBRARY
PYTHON_LIBRARIES is the canonical variable set by FindPythonLibs while
PYTHON_LIBRARY is an implementation detail. This replaces the uses of
the latter with the former.
2020-01-02 13:01:17 -08:00
Saleem Abdulrasool abb0075306 build: reduce CMake handling for zlib
Rather than handling zlib handling manually, use `find_package` from CMake
to find zlib properly. Use this to normalize the `LLVM_ENABLE_ZLIB`,
`HAVE_ZLIB`, `HAVE_ZLIB_H`. Furthermore, require zlib if `LLVM_ENABLE_ZLIB` is
set to `YES`, which requires the distributor to explicitly select whether
zlib is enabled or not. This simplifies the CMake handling and usage in
the rest of the tooling.

This restores 68a235d07f,
e6c7ed6d21.  The problem with the windows
bot is a need for clearing the cache.
2020-01-02 11:19:12 -08:00
James Henderson e406cca5f9 Revert "build: reduce CMake handling for zlib"
This reverts commit 68a235d07f.

This commit broke the clang-x64-windows-msvc build bot and a follow-up
commit did not fix it. Reverting to fix the bot.
2020-01-02 16:02:10 +00:00
Raphael Isemann a95f4c8784 [lldb][NFC] Remove unused variable in DWARFASTParserClang::ParseSingleMember 2020-01-02 11:57:00 +01:00
Raphael Isemann fe8e25a48a [lldb][NFC] Create type-safe function for creating a CompilerType from a QualType
LLDB frequently converts QualType to CompilerType. This is currently done like this:
    result = CompilerType(this, qual_type_var.getAsOpaquePtr())
There are a few shortcomings in this current approach:
  1. CompilerType's constructor takes a void* pointer so it isn't type safe.
  2. We can't add any sanity checks to the CompilerType constructor (e.g. that the type
     actually belongs to the passed ClangASTContext) without expanding the TypeSystem API.
  3. The logic for converting QualType->CompilerType is spread out over all of LLDB so
     changing it is difficult (e.g., what if we want to just pass the type ptr and not the
     1type_ptr | qual_flags1 to CompilerType).

This patch adds a `ClangASTContext::GetType` function similar to the other GetTypeForDecl
functions that does this conversion in a type safe way.

It also adds a sanity check for Tag-based types that the type actually belongs to the
current ClangASTContext (Types don't seem to know their ASTContext, so we have to
workaround by looking at the decl for the underlying TagDecl. This doesn't cover all types
we construct but it's better than no sanity check).
2020-01-02 11:54:45 +01:00
Saleem Abdulrasool 68a235d07f build: reduce CMake handling for zlib
Rather than handling zlib handling manually, use `find_package` from CMake
to find zlib properly. Use this to normalize the `LLVM_ENABLE_ZLIB`,
`HAVE_ZLIB`, `HAVE_ZLIB_H`. Furthermore, require zlib if `LLVM_ENABLE_ZLIB` is
set to `YES`, which requires the distributor to explicitly select whether
zlib is enabled or not. This simplifies the CMake handling and usage in
the rest of the tooling.
2020-01-01 16:36:59 -08:00
Raphael Isemann 8dbe2f02c6 [lldb][NFC] Simplify CompilerType constructors/destructors and fix unused variable warning
CompilerType has no virtual functions and no statements in its constructors,
so we can simplify this code. This also allows Clang to emit unused variable warnings
for CompilerType, so I also removed one unused variable that otherwise causes -Werror
builds to fail.
2020-01-01 22:56:16 +01:00
Mark de Wever 8dc7b982b4 [NFC] Fixes -Wrange-loop-analysis warnings
This avoids new warnings due to D68912 adds -Wrange-loop-analysis to -Wall.

Differential Revision: https://reviews.llvm.org/D71857
2020-01-01 20:01:37 +01:00
Raphael Isemann b1fb07ddba [lldb][NFC] Simplify ClangASTContext::GetTypeForDecl
Also removes the GetASTContext call from this code.
2019-12-30 00:22:23 +01:00
Raphael Isemann 0007f9da7c [lldb][NFC] Delete static versions of ClangASTContext::CreateFunctionType
We can always call the member function version of this function.
2019-12-29 20:27:05 +01:00
Raphael Isemann 36fb199eca [lldb][NFC] Remove GetASTContext call in ClangPersistentVariables
We try to build a CompilerType from the persistent decls so we need
a ClangASTContext. With this patch the ClangPersistentVariables store
the associated ClangASTContext of the persistent decls (which is
always the scratch ClangASTContext) and no longer call GetASTContext
to map back from clang::ASTContext to ClangASTContext.
2019-12-28 22:45:23 +01:00
Raphael Isemann 8612e92ed5 [lldb][NFC] Remove GetASTContext call in ClangDeclVendor
Instead of returning NamedDecls and then calling GetASTContext
to find back the ClangASTContext we used can just implement the
FindDecl variant that returns CompilerDecls (and implement the
other function by throwing away the ClangASTContext part of the
compiler decl).
2019-12-28 15:20:19 +01:00
Tatyana Krasnukha b0469eede2 [lldb][NFC] Move lock scope where it should begin 2019-12-26 18:49:35 +03:00
Raphael Isemann 37339d1426 [lldb][NFC] Use ClangASTContext in AppleObjCRuntime interfaces
This code actually needs a ClangASTContext but instead takes a
clang::ASTContext and then retrieves the original ClangASTContext
via the global map of ClangASTContexts. Let's change it so
that it takes a ClangASTContext which is simpler and faster.
2019-12-26 16:23:40 +01:00
Raphael Isemann b036f557ce [lldb] Remove some calls to GetASTContext
GetASTContext is really expensive to call as it makes use of the global
mapping from ASTContext to ClangASTContext. This replaces all calls where
we already have the ClangASTContext around and don't need to call
GetASTContext again.
2019-12-26 10:36:36 +01:00
Raphael Isemann caf460d979 [lldb][NFC] Use StringRef in ClangASTContext::GetBuiltinTypeForDWARFEncodingAndBitSize 2019-12-25 19:02:40 +01:00
Kamil Rytarowski ab8a7a29bf [lldb] Adapt for NetBSD-9.99.30 ptrace(2) API changes
Switch from PT_LWPINFO to PT_LWPSTATUS/PT_LWPNEXT.

Keep compat support for < 9.99.30.

No functional change intended.
2019-12-24 20:36:23 +01:00
Raphael Isemann 4657a397c2 [lldb][NFC] Remove ClangExternalASTSourceCommon
ClangExternalASTSourceCommon's purpose is to store a map from
Decl*/Type* to ClangASTMetadata. Usually this data is accessed
via the ClangASTContext interface which then grabs the
current ExternalASTSource of its ASTContext, tries to cast it
to ClangExternalASTSourceCommon and then accesses the metadata
map. If the casting fails the setter does nothing and the getter
returns a nullptr as if there was no known metadata for a type/decl.

This system breaks as soon as any non-LLDB ExternalASTSource is added via
a multiplexer to our existing ExternalASTSource (in which case we suddenly
loose all out metadata as the casting always fails with an ExternalASTSource
that is not inheriting from ClangExternalASTSourceCommon).

This patch moves the metadata map to the ClangASTContext. This gets
rid of all the fragile casting, the requirement that every ExternalASTSource in
LLDB has to inherit from ClangExternalASTSourceCommon and simplifies
the metadata implementation to a simple map lookup. As ClangExternalASTSourceCommon
had no other purpose than storing metadata, this patch deletes this class
and replaces all uses with clang::ExternalASTSource.

No other code changes in this commit beside the AppleObjCDeclVendor which
was the only code that did not use the ClangASTContext interface but directly
accessed the ClangExternalASTSourceCommon.
2019-12-24 13:17:27 +01:00
Jonas Devlieghere ebcb36d4a1 Revert "[lldb] Don't process symlinks deep inside DWARFUnit"
This temporarily reverts commit 3cfb6677b2
because it breaks TestCompDirSymLink.py on macOS.
2019-12-23 18:04:29 -08:00
Pavel Labath e40ac74dac [lldb] Remove DWARFUnit::AppendDIEsWithTag
This function is not very useful, as it's forcing a materialization of
the returned DIEs, and calling it is not substantially simpler than just
iterating over the DIEs manually. Delete it, and rewrite the single
caller.
2019-12-23 15:50:30 +01:00
Pavel Labath 46f02fc922 [lldb/DWARF] Fix hostname-stripping logic
This bit of code is trying to strip everything up to the first colon
from all debug info paths, as dwarf2 recommends this syntax for storing
the compilation host name. However, this code was too eager, and it
ended up stripping the entire compilation directory, if it did not
contain a forward slash (or a "x:\").

Normally this does not matter, as all absolute paths will contain one of
these patterns, but this does not have to be the case in case the debug
info is produced by "clang -fdebug-compilation-dir", which can end up
producing a relative compilation directory with no slashes (this is one
of the techniques for producing "relocatable" debug info).
2019-12-23 14:54:22 +01:00
Raphael Isemann b6c29d9de0 [lldb][NFC] Remove unused 'type' parameter in ClangExpressionDeclMap::FindGlobalVariable
We never pass something else than a nullptr as the 'type' so the related code in this function is never reached.
2019-12-23 12:43:47 +01:00
Raphael Isemann 73951a11c6 [lldb] Add sanity check to CreateDeclContext and fixed illformed CompilerContext in ClangExpressionDeclMap.
This adds a check that the ClangASTContext actually fits to the
DeclContext that we want to create a CompilerDeclContext for. If
the ClangASTContext (and its associated ASTContext) does not fit
to the DeclContext (that is, the DeclContext wasn't created by the
ASTContext), all computations using this malformed CompilerDeclContext
will yield unpredictable results.

Also fixes the only place that actually hits this assert which is the
construction of a CompilerDeclContext in ClangExpressionDeclMap
where we pass an unrelated ASTContext instead of the ASTContext
of the current expression.

I had to revert my previous change to DWARFASTParserClangTests.cpp
back to using the unsafe direct construction of CompilerDeclContext
as this assert won't work if the DeclContext we pass isn't a valid
DeclContext in the first place.
2019-12-23 11:48:02 +01:00
Pavel Labath 3cfb6677b2 [lldb] Don't process symlinks deep inside DWARFUnit
Summary:
This code is handling debug info paths starting with /proc/self/cwd,
which is one of the mechanisms people use to obtain "relocatable" debug
info (the idea being that one starts the debugger with an appropriate
cwd and things "just work").

Instead of resolving the symlinks inside DWARFUnit, we can do the same
thing more elegantly by hooking into the existing Module path remapping
code. Since llvm::DWARFUnit does not support any similar functionality,
doing things this way is also a step towards unifying llvm and lldb
dwarf parsers.

Reviewers: JDevlieghere, aprantl, clayborg, jdoerfert

Subscribers: lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D71770
2019-12-23 11:24:04 +01:00
Raphael Isemann 42ec584a8b [lldb][NFC] Make CompilerDeclContext construction type safe
The CompilerDeclContext constructor takes a void* pointer which
means that all callers of this constructor need to first explicitly
convert all pointers to clang::DeclContext*. This causes that we
for example can't just pass a TranslationUnitDecl* to the constructor without
first casting it to its parent class (as it inherits from both
Decl and DeclContext so the void* pointer is actually a Decl*).

This patch introduces a utility function in the ClangASTContext
which gets rid of the requirement to cast all pointers to
clang::DeclContext. Also moves all constructor calls to use this
function instead which is NFC (beside the change in
DWARFASTParserClangTests.cpp).
2019-12-23 09:56:54 +01:00
Jonas Devlieghere 1562511275 [lldb/ScriptInterpreter] Remove can_reload which is always true (NFC)
The `-r` option for `command script import` is there for legacy
compatibility, however the can_reload flag is always set to true. This
patch removes the flag and any code that relies on it being false.
2019-12-22 21:36:03 -08:00
Jonas Devlieghere 4164be7206 [Lldb/Lua] Persist Lua state across script interpreter calls.
Don't create a new lua state on every operation. Share a single state
across the lifetime of the script interpreter. Add simple locking to
prevent two threads from modifying the state concurrently.
2019-12-21 15:00:35 -08:00
Raphael Isemann f9f49d3594 [lldb][NFC] Return a reference from ClangASTContext::getASTContext and remove dead nullptr checks
ClangASTContext::getASTContext() currently returns a ptr but we have an assert there since a
while that the ASTContext is not a nullptr. This causes that we still have a lot of code
that is doing nullptr checks on the result of getASTContext() which is all unreachable code.

This patch changes the return value to a reference to make it clear this can't be a nullptr
and deletes all the nullptr checks.
2019-12-21 22:51:35 +01:00
Jonas Devlieghere bf03e17c57 [Lldb/Lua] Generate Lua Bindings
This patch uses SWIG to generate the Lua bindings for the SB API. It
covers most of the API, but some methods require a type map similar to
Python.

Discussion on the mailing list:
http://lists.llvm.org/pipermail/lldb-dev/2019-December/015812.html

Differential revision: https://reviews.llvm.org/D71235
2019-12-21 11:28:41 -08:00
Raphael Isemann 49b206f958 [lldb][NFC] Remove all ASTContext getter wrappers from ClangASTContext
Their naming is misleading as they only return the
ClangASTContext-owned variables. For ClangASTContext instances constructed
for a given clang::ASTContext they silently generated duplicated instances
(e.g., a second IdentifierTable) that were essentially unusable.

This removes all these getters as they are anyway not very useful in comparison
to just calling the clang::ASTContext getters. The initialization
code has been moved to the CreateASTContext initialization method so that all
code for making our own clang::ASTContext is in one place.
2019-12-21 15:41:18 +01:00
Pavel Labath 1805d1f87d [lldb] Fix -Wstringop-truncation in PythonReadline.cpp
The size is known and the truncation is deliberate -- use memcpy instead
of strncpy.
2019-12-21 11:35:26 +01:00
Jan Kratochvil df6879ec02 [lldb] Fix ARM32 inferior calls
echo -e '#include <unistd.h>\nint main(void){\nsync();return 0;}'|./bin/clang -g -x c -;./bin/lldb -o 'file ./a.out' -o 'b main' -o r -o 'p (void)sync()'

Actual:

  error: Expression can't be run, because there is no JIT compiled function

Expected:

  <nothing, sync() has been executed>

This patch has been checked by:
  D71707: clang-tidy: new bugprone-pointer-cast-widening
  https://reviews.llvm.org/D71707

Casting from 32-bit `void *` to `uint64_t` requires an intermediate `uintptr_t` cast otherwise the pointer gets sign-extended:

  echo -e '#include <stdio.h>\n#include <stdint.h>\nint main(void){void *p=(void *)0x80000000;unsigned long long ull=(unsigned long long)p;unsigned long long ull2=(unsigned long
long)(uintptr_t)p;printf("p=%p ull=0x%llx ull2=0x%llx\\n",p,ull,ull2);return 0;}'|gcc -Wall -m32 -x c -;./a.out
  <stdin>: In function ‘main’:
  <stdin>:3:66: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
  p=0x80000000 ull=0xffffffff80000000 ull2=0x80000000

With debug output:
Actual:

  IRMemoryMap::WriteMemory (0xb6ff8640, 0xffffffffb6f82158, 0x112) went to [0xb6ff8640..0xb6ff86b3)
  Code can be run in the target.
  Found function, has local address 0xffffffffb6f84000 and remote address 0xffffffffffffffff
  Couldn't disassemble function : Couldn't find code range for function _Z12$__lldb_exprPv
  Sections:
  [0xb6f84000+0x3c]->0xb6ff9020 (alignment 4, section ID 0, name .text)
  ...
  HandleCommand, command did not succeed
  error: Expression can't be run, because there is no JIT compiled function

Expected:

  IRMemoryMap::WriteMemory (0xb6ff8640, 0xb6faa15c, 0x128) went to [0xb6ff8640..0xb6ff86c3)
  IRExecutionUnit::GetRemoteAddressForLocal() found 0xb6fac000 in [0xb6fac000..0xb6fac040], and returned 0xb6ff9020 from [0xb6ff9020..0xb6ff9060].
  Code can be run in the target.
  Found function, has local address 0xb6fac000 and remote address 0xb6ff9020
  Function's code range is [0xb6ff9020+0x40]
  ...
  Function data has contents:
  0xb6ff9020: 10 4c 2d e9 08 b0 8d e2 08 d0 4d e2 00 40 a0 e1
  ...
  Function disassembly:
  0xb6ff9020: 0xe92d4c10   push   {r4, r10, r11, lr}

Differential revision: https://reviews.llvm.org/D71498
2019-12-21 11:12:17 +01:00
Adrian Prantl 44b4b833ad Rename DW_AT_LLVM_isysroot to DW_AT_LLVM_sysroot
This is a purely cosmetic change that is NFC in terms of the binary
output. I bugs me that I called the attribute DW_AT_LLVM_isysroot
since the "i" is an artifact of GCC command line option syntax
(-isysroot is in the category of -i options) and doesn't carry any
useful information otherwise.

This attribute only appears in Clang module debug info.

Differential Revision: https://reviews.llvm.org/D71722
2019-12-20 13:11:17 -08:00
Jonas Devlieghere 2861324208 [lldb/Lua] Implement a Simple Lua Script Interpreter Prototype
This implements a very elementary Lua script interpreter. It supports
running a single command as well as running interactively. It uses
editline if available. It's still missing a bunch of stuff though. Some
things that I intentionally ingored for now are that I/O isn't properly
hooked up (so every print goes to stdout) and the non-editline support
which is not handling a bunch of corner cases. The latter is a matter of
reusing existing code in the Python interpreter.

Discussion on the mailing list:
http://lists.llvm.org/pipermail/lldb-dev/2019-December/015812.html

Differential revision: https://reviews.llvm.org/D71234
2019-12-20 11:19:47 -08:00
Raphael Isemann 6be76f491f [lldb][NFC] Remove redundant ASTContext args to CopyDecl/DeportDecl
We already pass a Decl here and the additional ASTContext needs to
match the Decl. We might as well just pass the Decl and then extract
the ASTContext from that.
2019-12-20 18:45:14 +01:00
Johannes Altmanninger 92211bf0f1 [LLDB] Fix address computation for inline function
Summary:
Fixes PR41237 - SIGSEGV on call expression evaluation when debugging clang

When linking multiple compilation units that define the same functions,
the functions is merged but their debug info is not. This ignores debug
info entries for functions in a non-executable sections; those are
functions that were definitely dropped by the linker.

Reviewers: spyffe, clayborg, jasonmolenda

Reviewed By: clayborg

Subscribers: labath, aprantl, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D71487
2019-12-20 09:04:45 +01:00
Jonas Devlieghere 67de896229 [lldb/Lua] Add Boilerplate for a Lua Script Interpreter
This adds the boilerplate necessary to support the Lua script
interpreter. The interpreter is not functional yet and just reports that
it's not implemented.

Discussion on the mailing list:
http://lists.llvm.org/pipermail/lldb-dev/2019-December/015812.html

Differential revision: https://reviews.llvm.org/D71232
2019-12-19 10:13:51 -08:00
Jason Molenda 7026b34702 make err msg in MachSymtabSectionInfo::GetSection clear about the file
This error message didn't specify which file was malformed, so
there's some hunting-around required if it comes up.  We have the
filename; include it in the error message.
2019-12-18 16:13:17 -08:00
Jonas Devlieghere e194d89012 [lldb/MachO] "Fix" intentional out-of-bounds error (NFC)
Remove the hack that populates the cpsr register in the gpr struct by
writing past the end of the array. This was tripping up ASan.

Patch by: Reva Cuthbertson
2019-12-18 12:54:04 -08:00
Raphael Isemann d8a3194987 [lldb][NFC] Add unit test for persistent variable lookup with ClangExpressionDeclMap
This adds a unit test for looking up persistent declarations in the scratch AST
context. Also adds the `GetPersistentDecl` hook to the ClangExpressionDeclMap
that this unit test can emulate looking up persistent variables without having
a lldb_private::Target.
2019-12-18 13:50:05 +01:00
Raphael Isemann 268f37df6e [lldb][NFC] Use StringRef in CreateRecordType and CreateObjCClass 2019-12-17 16:10:34 +01:00
Raphael Isemann b852b3c982 [lldb][NFC] Rename ClangASTImporter::InsertRecordDecl to SetRecordLayout and document it
This function is just setting the layout for the given RecordDecl so
the current name is not very descriptive. Also add some documentation for it.
2019-12-17 15:56:07 +01:00
Raphael Isemann 4aee81c4f7 [lldb][NFC] Allow creating ClangExpressionDeclMap and ClangASTSource without a Target and add basic unit test
The ClangExpressionDeclMap should be testable from a unit test. This is currently
impossible as they have both dependencies on Target/ExecutionContext from their
constructor. This patch allows constructing these classes without an active Target
and adds the missing tests for running without a target that we can do at least
a basic lookup test without crashing.
2019-12-17 14:04:12 +01:00
Raphael Isemann ff0102b32c [lldb] Remove modern-type-lookup
Summary:
As discussed on the mailing list [1] we have to make a decision for how to proceed with the modern-type-lookup.

This patch removes modern-type-lookup from LLDB. This just removes all the code behind the modern-type-lookup
setting but it does *not* remove any code from Clang (i.e., the ExternalASTMerger and the clang-import-test stay around
for now).

The motivation for this is that I don't think that the current approach of implementing modern-type-lookup
will work out. Especially creating a completely new lookup system behind some setting that is never turned on by anyone
and then one day make one big switch to the new system seems wrong. It doesn't fit into the way LLVM is developed and has
so far made the transition work much more complicated than it has to be.

A lot of the benefits that were supposed to come with the modern-type-lookup are related to having a better organization
in the way types move across LLDB and having less dependencies on unrelated LLDB code. By just looking at the current code (mostly
the ClangASTImporter) I think we can reach the same goals by just incrementally cleaning up, documenting, refactoring
and actually testing the existing code we have.

[1] http://lists.llvm.org/pipermail/lldb-dev/2019-December/015831.html

Reviewers: shafik, martong

Subscribers: rnkovacs, christof, arphaman, JDevlieghere, usaxena95, lldb-commits, friss

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D71562
2019-12-17 12:24:31 +01:00
Raphael Isemann d9ca412a8a [lldb][NFC] Remove all unnecessary includes for ClangASTSourceCommon.h
These files only need the definition of ClangASTMetadata (which was
previously in the ClangASTSourceCommon.h) or don't need the include at all.
2019-12-17 11:21:11 +01:00
Raphael Isemann d5b54bbfaf [lldb] Add support for calling objc_direct methods from LLDB's expression evaluator.
Summary:
D69991 introduced `__attribute__((objc_direct))` that allows directly calling methods without message passing.
This patch adds support for calling methods with this attribute to LLDB's expression evaluator.

The patch can be summarised in that LLDB just adds the same attribute to our module AST when we find a
method with `__attribute__((objc_direct))` in our debug information.

Reviewers: aprantl, shafik

Reviewed By: shafik

Subscribers: JDevlieghere, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D71196
2019-12-17 10:28:40 +01:00
Raphael Isemann 75e8a91cf8 [lldb][NFC] Remove all overloads of Copy/DeportType in ClangASTImporter
The overloads that don't take a CompilerType serve no purpose as we
always have a CompilerType in the scope where we call them. Instead
just call the overload that takes a CompilerType and delete the
now unused other overloaded methods.
2019-12-16 12:09:05 +01:00
Raphael Isemann 64678ef9f2 [lldb][NFC] Remove ClangASTImporter::ResolveDeclOrigin
ResolveDeclOrigin was just an inconvenience method around GetDeclOrigin.
2019-12-16 09:16:33 +01:00
Jonas Devlieghere 4e26cf2cfb [lldb/CMake] Rename LLDB_DISABLE_PYTHON to LLDB_ENABLE_PYTHON
This matches the naming scheme used by LLVM and all the other optional
dependencies in LLDB.

Differential revision: https://reviews.llvm.org/D71482
2019-12-13 13:41:11 -08:00