Currently, our unwinder assumes that the functions are continuous (or at
least, that there are no functions which are "in the middle" of other
functions). Neither of these assumptions is true for functions optimized
by tools like propeller and (probably) bolt.
While there are many things that go wrong for these functions, the
biggest damage is caused by the unwind plan caching code, which
currently takes the maximalist extent of the function and assumes that
the unwind plan we get for that is going to be valid for all code inside
that range. If a part of the function has been moved into a "cold"
section, then the range of the function can be many megabytes, meaning
that any function within that range will probably fail to unwind.
We end up with this maximalist range because the unwinder asks for the
Function object for its range. This is only one of the strategies for
determining the range, but it is the first one -- and also the most
incorrect one. The second choice would is asking the eh_frame section
for the range of the function, and this one returns something reasonable
here (the address range of the current function fragment) -- which it
does because each fragment gets its own eh_frame entry (it has to,
because they have to be continuous).
With this in mind, this patch moves the eh_frame (and debug_frame) to
the front of the queue. I think that preferring this range makes sense
because eh_frame is one of the unwind plans that we return, and some
others (augmented eh_frame) are based on it. In theory this could break
some functions, where the debug info and eh_frame disagree on the extent
of the function (and eh_frame is the one who's wrong), but I don't know
of any such scenarios.
Fixed the error `unable to create target: 'No available targets are
compatible with triple "x86_64-apple-macosx10.4.0"'` running `clang
--target=x86_64-apple-macosx -c -gdwarf -o %t %s`.
Add an "always on" log category and channel. Unlike other, existing log
channels, it is not exposed to users. The channel is meant to be used
sparsely and deliberately for logging high-value information to the
system log.
We have a similar concept in the downstream Swift fork and this has
proven to be extremely valuable. This is especially true on macOS where
system log messages are automatically captured as part of a sysdiagnose.
1. This commit adds LLDB_TEST_PLATFORM_URL, LLDB_TEST_SYSROOT,
LLDB_TEST_PLATFORM_WORKING_DIR, LLDB_SHELL_TESTS_DISABLE_REMOTE cmake
flags to pass arguments for cross-compilation and remote running of both Shell&API tests.
2. To run Shell tests remotely, it adds 'platform select' and 'platform connect' commands to %lldb
substitution.
3. 'remote-linux' feature added to lit to disable tests failing with
remote execution.
4. A separate working directory is assigned to each test to avoid
conflicts during parallel test execution.
5. Remote Shell testing is run only when LLDB_TEST_SYSROOT is set for
building test sources. The recommended compiler for that is Clang.
---------
Co-authored-by: Vladimir Vereschaka <vvereschaka@accesssoftek.com>
Listen to gdbserver-port, accept the connection and run `lldb-server gdbserver --fd` on all platforms.
Parameters --min-gdbserver-port and --max-gdbserver-port are deprecated now.
This is the part 2 of #101283.
Fixes#97537.
LLDB code for using the type layout data from DWARF was not kicking in
for types which were initially parsed from a declaration. The problem
was in these lines of code:
```
if (type)
layout_info.bit_size = type->GetByteSize(nullptr).value_or(0) * 8;
```
which determine the types layout size by getting the size from the
lldb_private::Type object. The problem is that if the type object does
not have this information cached, this request can trigger another
(recursive) request to lay out/complete the type. This one, somewhat
surprisingly, succeeds, but does that without the type layout
information (because it hasn't been computed yet). The reasons why this
hasn't been noticed so far are:
- this is a relatively new bug. I haven't checked but I suspect it was
introduced in the "delay type definition search" patchset from this
summer -- if we search for the definition eagerly, we will always have a
cached size value.
- it requires the presence of another bug/issue, as otherwise the
automatically computed layout will match the real thing.
- it reproduces (much) more easily with -flimit-debug-info (though it is
possible to trigger it without that flag).
My fix consists of always fetching type size information from DWARF
(which so far existed as a fallback path). I'm not quite sure why this
code was there in the first place (the code goes back to before the
Great LLDB Reformat), but I don't believe it is necessary, as the type
size (for types parsed from definition DIEs) is set exactly from this
attribute (in ParseStructureLikeDIE).
This patch is a reworking of Pete Lawrence's (@PortalPete) proposal
for better expression evaluator error messages:
https://github.com/llvm/llvm-project/pull/80938
Before:
```
$ lldb -o "expr a+b"
(lldb) expr a+b
error: <user expression 0>:1:1: use of undeclared identifier 'a'
a+b
^
error: <user expression 0>:1:3: use of undeclared identifier 'b'
a+b
^
```
After:
```
(lldb) expr a+b
^ ^
│ ╰─ error: use of undeclared identifier 'b'
╰─ error: use of undeclared identifier 'a'
```
This eliminates the confusing `<user expression 0>:1:3` source
location and avoids echoing the expression to the console again, which
results in a cleaner presentation that makes it easier to grasp what's
going on. You can't see it here, bug the word "error" is now also in
color, if so desired.
Depends on https://github.com/llvm/llvm-project/pull/106442.
This patch is a reworking of Pete Lawrence's (@PortalPete) proposal
for better expression evaluator error messages:
https://github.com/llvm/llvm-project/pull/80938
Before:
```
$ lldb -o "expr a+b"
(lldb) expr a+b
error: <user expression 0>:1:1: use of undeclared identifier 'a'
a+b
^
error: <user expression 0>:1:3: use of undeclared identifier 'b'
a+b
^
```
After:
```
(lldb) expr a+b
^ ^
│ ╰─ error: use of undeclared identifier 'b'
╰─ error: use of undeclared identifier 'a'
```
This eliminates the confusing `<user expression 0>:1:3` source
location and avoids echoing the expression to the console again, which
results in a cleaner presentation that makes it easier to grasp what's
going on. You can't see it here, bug the word "error" is now also in
color, if so desired.
Depends on https://github.com/llvm/llvm-project/pull/106442.
This attempts to improve user-experience when LLDB stops on a
verbose_trap. Currently if a `__builtin_verbose_trap` triggers, we
display the first frame above the call to the verbose_trap. So in the
newly added test case, we would've previously stopped here:
```
(lldb) run
Process 28095 launched: '/Users/michaelbuch/a.out' (arm64)
Process 28095 stopped
* thread #1, queue = 'com.apple.main-thread', stop reason = Bounds error: out-of-bounds access
frame #1: 0x0000000100003f5c a.out`std::__1::vector<int>::operator[](this=0x000000016fdfebef size=0, (null)=10) at verbose_trap.cpp:6:9
3 template <typename T>
4 struct vector {
5 void operator[](unsigned) {
-> 6 __builtin_verbose_trap("Bounds error", "out-of-bounds access");
7 }
8 };
```
After this patch, we would stop in the first non-`std` frame:
```
(lldb) run
Process 27843 launched: '/Users/michaelbuch/a.out' (arm64)
Process 27843 stopped
* thread #1, queue = 'com.apple.main-thread', stop reason = Bounds error: out-of-bounds access
frame #2: 0x0000000100003f44 a.out`g() at verbose_trap.cpp:14:5
11
12 void g() {
13 std::vector<int> v;
-> 14 v[10];
15 }
16
```
rdar://134490328
This bug surfaced after https://github.com/llvm/llvm-project/pull/105865
(currently reverted, but blocked on this to be relanded).
Because Clang doesn't emit `DW_TAG_member`s for unnamed bitfields, LLDB
has to make an educated guess about whether they existed in the source.
It does so by checking whether there is a gap between where the last
field ended and the currently parsed field starts. In the example test
case, the empty field `padding` was folded into the storage of `data`.
Because the `bit_offset` of `padding` is `0x0` and its `DW_AT_byte_size`
is `0x1`, LLDB thinks the field ends at `0x1` (not quite because we
first round the size to a word size, but this is an implementation
detail), erroneously deducing that there's a gap between `flag` and
`padding`.
This patch adds the notion of "effective field end", which accounts for
fields that share storage. It is set to the end of the storage that the
two fields occupy. Then we use this to check for gaps in the unnamed
bitfield creation logic.
Print a warning when the debugger detects a mismatch between the MD5
checksum in the DWARF 5 line table and the file on disk. The warning is
printed only once per file.
This is the root-cause for the LLDB failures that started occurring
after https://github.com/llvm/llvm-project/pull/105865.
The DWARFASTParserClang has logic to try derive unnamed bitfields from
DWARF offsets. In this case we treat `padding` as a 1-byte size field
that would overlap with `flag`, and decide we need to introduce an
unnamed bitfield into the AST, which is incorrect.
This allows e.g. DWARFDIE::GetName() to return the name of the type when
looking at its declaration (which contains only
DW_AT_declaration+DW_AT_signature). This is similar to how we recurse
through DW_AT_specification when looking for a function name. Llvm dwarf
parser has obtained the same functionality through #99495.
This fixes a bug where we would confuse a type like NS::Outer::Struct
with NS::Struct (because NS::Outer (and its name) was in a type unit).
We need to resolve the type signature to get a hold of the template
argument dies.
The associated test case passes even without this patch, but it only
does it by accident (because the subsequent code considers the types to
be in an anonymous namespace and this not subject to uniqueing). This
will change once my other patch starts resolving names correctly.
[D156118](https://reviews.llvm.org/D156118) states that this note is
always present, but it is better to check it explicitly, as otherwise
`lldb` may crash when trying to read registers.
In f9f3316, Adrian fixed an issue where LLDB wouldn't update the
target's architecture when the process reported a different triple that
only differed in its sub-architecture.
This unintentionally regressed core file debugging when the core file
reports the base architecture (e.g. armv7) while the main binary knows
the correct CPU subtype (e.g. armv7em). After the aforementioned change,
we update the target architecture from armv7em to armv7. Fix the issue
by trusting the target architecture over the ProcessMachCore process.
rdar://133834304
This recently added test is failing on Windows with:
```
c:\users\tcwg\llvm-worker\lldb-aarch64-windows\build\bin\lldb.exe --no-lldbinit -S C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/tools/lldb\test\Shell\lit-lldb-init-quiet C:\Users\tcwg\llvm-worker\lldb-aarch64-windows\build\tools\lldb\test\Shell\Expr\Output\TestAnonNamespaceParamFunc.cpp.tmp -o run -o "expression func(a)" -o exit | c:\users\tcwg\llvm-worker\lldb-aarch64-windows\build\bin\filecheck.exe C:\Users\tcwg\llvm-worker\lldb-aarch64-windows\llvm-project\lldb\test\Shell\Expr\TestAnonNamespaceParamFunc.cpp
executed command: 'c:\users\tcwg\llvm-worker\lldb-aarch64-windows\build\bin\lldb.exe' --no-lldbinit -S 'C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/tools/lldb\test\Shell\lit-lldb-init-quiet' 'C:\Users\tcwg\llvm-worker\lldb-aarch64-windows\build\tools\lldb\test\Shell\Expr\Output\TestAnonNamespaceParamFunc.cpp.tmp' -o run -o 'expression func(a)' -o exit
.---command stderr------------
| TestAnonNamespaceParamFunc.cpp.tmp :: Class 'tagARRAYDESC' has a member 'tdescElem' of type 'tagTYPEDESC' which does not have a complete definition.error: TestAnonNamespaceParamFunc.cpp.tmp :: Class 'tagARRAYDESC' has a member 'tdescElem' of type 'tagTYPEDESC' which does not have a complete definition.
| (lldb) TestAnonNamespaceParamFunc.cpp.tmp :: Class 'std::partial_ordering' has a member 'less' of type 'std::partial_ordering' which does not have a complete definition.error: TestAnonNamespaceParamFunc.cpp.tmp :: Class 'std::partial_ordering' has a member 'less' of type 'std::partial_ordering' which does not have a complete definition.
| (lldb) TestAnonNamespaceParamFunc.cpp.tmp :: Class 'std::strong_ordering' has a member 'less' of type 'std::strong_ordering' which does not have a complete definition.error: TestAnonNamespaceParamFunc.cpp.tmp :: Class 'std::strong_ordering' has a member 'less' of type 'std::strong_ordering' which does not have a complete definition.
| (lldb) TestAnonNamespaceParamFunc.cpp.tmp :: Class 'std::weak_ordering' has a member 'less' of type 'std::weak_ordering' which does not have a complete definition.error: TestAnonNamespaceParamFunc.cpp.tmp :: Class 'std::weak_ordering' has a member 'less' of type 'std::weak_ordering' which does not have a complete definition.
| (lldb) error: Couldn't look up symbols:
| int func(struct `anonymous namespace'::InAnon)
| Hint: The expression tried to call a function that is not present in the target, perhaps because it was optimized out by the compiler.
`-----------------------------
executed command: 'c:\users\tcwg\llvm-worker\lldb-aarch64-windows\build\bin\filecheck.exe' 'C:\Users\tcwg\llvm-worker\lldb-aarch64-windows\llvm-project\lldb\test\Shell\Expr\TestAnonNamespaceParamFunc.cpp'
.---command stderr------------
| C:\Users\tcwg\llvm-worker\lldb-aarch64-windows\llvm-project\lldb\test\Shell\Expr\TestAnonNamespaceParamFunc.cpp:10:11: error: CHECK: expected string not found in input
| // CHECK: (int) $0 = 15
| ^
| <stdin>:16:26: note: scanning from here
| (lldb) expression func(a)
| ^
```
So the function is still not callable. But AFAICT, this is not a
regression, since this function wasn't callable prior to the patch
anyway. I currently do not have a Windows setup to test this on,
so XFAIL for now.
This patch changes the test that uses the `cat -e` option to `cat -v` so
that the test can be run using lit's internal shell. For `cat`, the `-v`
option prints non-printing characters in ^ and M- notation, while the
`-e` option adds `$` to the end of lines in addition to printing
non-printing characters in ^ and M- notation. This is an alternative
patch to https://github.com/llvm/llvm-project/pull/102061, opting to
rewrite the test that uses `cat -e` instead of extending support to the
`-e` option.
Fixes https://github.com/llvm/llvm-project/issues/102377
While parsing an expression, Clang tries to diagnose usage of decls
(with possibly non-external linkage) for which it hasn't been provided
with a definition. This is the case, e.g., for functions with parameters
that live in an anonymous namespace (those will have `UniqueExternal`
linkage, this is computed [here in
computeTypeLinkageInfo](ea8bb4d633/clang/lib/AST/Type.cpp (L4647-L4653))).
Before diagnosing such situations, Clang calls
`ExternalSemaSource::ReadUndefinedButUsed`. The intended use of this API
is to extend the set of "used but not defined" decls with additional
ones that the external source knows about. However, in LLDB's case, we
never provide `FunctionDecl`s with a definition, and instead rely on the
expression parser to resolve those symbols by linkage name. Thus, to
avoid the Clang parser from erroring out in these situations, this patch
implements `ReadUndefinedButUsed` which just removes the "undefined"
non-external `FunctionDecl`s that Clang found.
We also had to add an `ExternalSemaSource` to the `clang::Sema` instance
LLDB creates. We previously didn't have any source on `Sema`. Because we
add the `ExternalASTSourceWrapper` here, that means we'd also
technically be adding the `ClangExpressionDeclMap` as an
`ExternalASTSource` to `Sema`, which is fine because `Sema` will only be
calling into the `ExternalSemaSource` APIs (though nothing currently
strictly enforces this, which is a bit worrying).
Note, the decision for whether to put a function into `UndefinedButUsed`
is done in
[Sema::MarkFunctionReferenced](ea8bb4d633/clang/lib/Sema/SemaExpr.cpp (L18083-L18087)).
The `UniqueExternal` linkage computation is done in
[getLVForNamespaceScopeDecl](ea8bb4d633/clang/lib/AST/Decl.cpp (L821-L833)).
Fixes https://github.com/llvm/llvm-project/issues/104712
The only change vs. the first version of the patch is that I've made
DWARFUnit linking thread-safe/unit. This was necessary because, during
the
indexing step, two skeleton units could attempt to associate themselves
with the split unit.
The original commit message was:
I ran into this when LTO completely emptied two compile units, so they
ended up with the same hash (see #100375). Although, ideally, the
compiler would try to ensure we don't end up with a hash collision even
in this case, guaranteeing their absence is practically impossible. This
patch ensures this situation does not bring down lldb.
This patch improves the ability of a ObjectFileELF instance to read the
.dynamic section. It adds the ability to read the .dynamic section from
the PT_DYNAMIC program header which is useful for ELF files that have no
section headers and for ELF files that are read from memory. It cleans
up the usage of the .dynamic entries so that
ObjectFileELF::ParseDynamicSymbols() is the only code that parses
.dynamic entries, teaches that function the read and store the string
values for each .dynamic entry. We now dump the .dynamic entries in the
output of "image dump objfile". It also cleans up the code that gets the
dynamic string table so that it can grab it from the DT_STRTAB and
DT_STRSZ .dynamic entries for when we have a ELF file with no section
headers or we are reading it from memory.
The test appears to be flaky. Revert it while I investigate.
This reverts commits 32a62ebdeab0c10d5311cf812e021717636d4514 and
7027cc6a073cb5ae7a0ce04fa4a2dbe714615da9.
The test appears to be flaky. Revert it while I investigate.
This reverts commits 7027cc6a073cb5ae7a0ce04fa4a2dbe714615da9 and
21ef272ec1974244710fc639f98674eae3f8b02c.
…Type
This is needed to ensure we find a type if its definition is in a CU
that wasn't indexed. This can happen if the definition is in some
precompiled code (e.g. the c++ standard library) which was built with
different flags than the rest of the binary.
I ran into this when LTO completely emptied two compile units, so they
ended up with the same hash (see #100375). Although, ideally, the
compiler would try to ensure we don't end up with a hash collision even
in this case, guaranteeing their absence is practically impossible. This
patch ensures this situation does not bring down lldb.
This patch improves the ability of a ObjectFileELF instance to read the .dynamic section. It adds the ability to read the .dynamic section from the PT_DYNAMIC program header which is useful for ELF files that have no section headers and for ELF files that are read from memory. It cleans up the usage of the .dynamic entries so that ObjectFileELF::ParseDynamicSymbols() is the only code that parses .dynamic entries, teaches that function the read and store the string values for each .dynamic entry. We now dump the .dynamic entries in the output of "image dump objfile". It also cleans up the code that gets the dynamic string table so that it can grab it from the DT_STRTAB and DT_STRSZ .dynamic entries for when we have a ELF file with no section headers or we are reading it from memory.
This fixes a regression caused by delayed type definition searching
(#96755 and friends): If we end up adding a member (e.g. a typedef) to a
type that we've already attempted to complete (and failed), the
resulting AST would end up inconsistent (we would start to "forcibly"
complete it, but never finish it), and importing it into an expression
AST would crash.
This patch fixes this by detecting the situation and finishing the
definition as well.
This patch renames the `scripting template` subcommand to be `scripting
extension` instead since that would make more sense for upcoming
commands.
Signed-off-by: Med Ismail Bennani <ismail@bennani.ma>
This is an alternative, much simpler implementation of #99305. In this
version I replace the AnyModule wildcard match with a special TypeQuery
flag which achieves (mostly) the same thing.
It is a preparatory step for teaching ContextMatches about anonymous
namespaces. It started out as a way to remove the assumption that the
pattern and target contexts must be of the same length -- that's will
not be correct with anonymous namespaces, and probably isn't even
correct right now for AnyModule matches.
For the same reasons as 6cfac497e96978f2bfc50a00b51c198f2ed50f82.
This test was added in https://github.com/llvm/llvm-project/pull/100710.
It fails because when we're linking with link.exe, -gdwarf has no
effect and we get a PDB file anyway. The Windows on Arm lldb bot
uses link.exe.
"C:\\Program Files\\Microsoft Visual Studio\\2022\\Community\\VC\\Tools\\MSVC\\14.34.31933\\bin\\Hostx86\\arm64\\link.exe" <...>
08/01/2024 01:47 PM 2,956,488 vla.cpp.ilk
08/01/2024 01:47 PM 6,582,272 vla.cpp.pdb
08/01/2024 01:47 PM 734,208 vla.cpp.tmp
Depends on https://github.com/llvm/llvm-project/pull/100674
Currently, we treat VLAs declared as `int[]` and `int[0]` identically.
I.e., we create them as `IncompleteArrayType`s. However, the
`DW_AT_count` for `int[0]` *does* exist, and is retrievable without an
execution context. This patch decouples the notion of "has 0 elements"
from "has no known `DW_AT_count`".
This aligns with how Clang represents `int[0]` in the AST (it treats it
as a `ConstantArrayType` of 0 size).
This issue was surfaced when adapting LLDB to
https://github.com/llvm/llvm-project/issues/93069. There, the
`__compressed_pair_padding` type has a `char[0]` member. If we
previously got the `__compressed_pair_padding` out of a module (where
clang represents `char[0]` as a `ConstantArrayType`), and try to merge
the AST with one we got from DWARF (where LLDB used to represent
`char[0]` as an `IncompleteArrayType`), the AST structural equivalence
check fails, resulting in silent ASTImporter failures. This manifested
in a failure in `TestNonModuleTypeSeparation.py`.
**Implementation**
1. Adjust `ParseChildArrayInfo` to store the element counts of each VLA
dimension as an `optional<uint64_t>`, instead of a regular `uint64_t`.
So when we pass this down to `CreateArrayType`, we have a better
heuristic for what is an `IncompleteArrayType`.
2. In `TypeSystemClang::GetBitSize`, if we encounter a
`ConstantArrayType` simply return the size that it was created with. If
we couldn't determine the authoritative bound from DWARF during parsing,
we would've created an `IncompleteArrayType`. This ensures that
`GetBitSize` on arrays with `DW_AT_count 0x0` returns `0` (whereas
previously it would've returned a `std::nullopt`, causing that
`FieldDecl` to just get dropped during printing)
The help output incorrectly states that this command takes a shared
library name (<shlib-name>) while really it takes a path to a symbol
file.
rdar://131777043
This patch adds a frame recognizer for Clang's
`__builtin_verbose_trap`, which behaves like a
`__builtin_trap`, but emits a failure-reason string into debug-info in
order for debuggers to display
it to a user.
The frame recognizer triggers when we encounter
a frame with a function name that begins with
`__clang_trap_msg`, which is the magic prefix
Clang emits into debug-info for verbose traps.
Once such frame is encountered we display the
frame function name as the `Stop Reason` and display that frame to the
user.
Example output:
```
(lldb) run
warning: a.out was compiled with optimization - stepping may behave oddly; variables may not be available.
Process 35942 launched: 'a.out' (arm64)
Process 35942 stopped
* thread #1, queue = 'com.apple.main-thread', stop reason = Misc.: Function is not implemented
frame #1: 0x0000000100003fa4 a.out`main [inlined] Dummy::func(this=<unavailable>) at verbose_trap.cpp:3:5 [opt]
1 struct Dummy {
2 void func() {
-> 3 __builtin_verbose_trap("Misc.", "Function is not implemented");
4 }
5 };
6
7 int main() {
(lldb) bt
* thread #1, queue = 'com.apple.main-thread', stop reason = Misc.: Function is not implemented
frame #0: 0x0000000100003fa4 a.out`main [inlined] __clang_trap_msg$Misc.$Function is not implemented$ at verbose_trap.cpp:0 [opt]
* frame #1: 0x0000000100003fa4 a.out`main [inlined] Dummy::func(this=<unavailable>) at verbose_trap.cpp:3:5 [opt]
frame #2: 0x0000000100003fa4 a.out`main at verbose_trap.cpp:8:13 [opt]
frame #3: 0x0000000189d518b4 dyld`start + 1988
```
PT_LOAD and PT_TLS segments are top level sections in the ObjectFileELF
section list. The two segments can often have the same program header
p_vaddr and p_paddr values and this can cause section load list issues
in LLDB if we load the PT_TLS segments. What happens is the
SectionLoadList::m_addr_to_sect, when a library is loaded, will first
map one of the sections named "PT_LOAD[0]" with the load address that
matches the p_vaddr entry from the program header. Then the "PT_TLS[0]"
would come along and try to load this section at the same address. This
would cause the "PT_LOAD[0]" section to be unloaded as the
SectionLoadList::m_addr_to_sect would replace the value for the matching
p_vaddr with the last section to be seen. The sizes of the PT_TLS and
PT_LOAD that have the same p_vaddr value don't need to have the same
byte size, so this could cause lookups to fail for an addresses in the
"PT_LOAD[0]" section or any of its children if the offset is greater
than the offset size of the PT_TLS segment. It could also cause us to
incorrectly attribute addresses from the "PT_LOAD[0]" to the "PT_TLS[0]"
segment when doing lookups for offset that are less than the size of the
PT_TLS segment.
This fix stops us from loading PT_TLS segments in the section load lists
and will prevent the bugs that resulted from this. No addresses the the
DWARF refer to TLS data with a "file address" in any way. They all have
TLS DWARF location expressions to locate these variables. We also don't
have any support for having actual thread specific sections and having
those sections resolve to something different for each thread, so there
currently is no point in loading thread specific sections. Both the
ObjectFileMachO and ObjectFileCOFF both ignore thread specific sections
at the moment, so this brings the ObjectFileELF to parity with those
plug-ins.
I added a test into an existing test to verify that things work as
expected.
Prior to this fix with a real binary, the output of "target dump
section-load-list" would look like this for the old LLDB:
```
// (lldb) target dump section-load-list
// addr = 0x0000000000000000, section = 0x55d46ab8c510: 0xfffffffffffffffd container [0x0000000000000000-0x0000000000000628) r-- 0x00000000 0x00000628 0x00000000 a.out.PT_LOAD[0]
// addr = 0x0000000000001000, section = 0x55d46ab8b0c0: 0xfffffffffffffffc container [0x0000000000001000-0x0000000000001185) r-x 0x00001000 0x00000185 0x00000000 a.out.PT_LOAD[1]
// addr = 0x0000000000002000, section = 0x55d46ac040f0: 0xfffffffffffffffb container [0x0000000000002000-0x00000000000020cc) r-- 0x00002000 0x000000cc 0x00000000 a.out.PT_LOAD[2]
// addr = 0x0000000000003db0, section = 0x55d46ab7cef0: 0xfffffffffffffff6 container [0x0000000000003db0-0x0000000000003db4) r-- 0x00002db0 0x00000000 0x00000000 a.out.PT_TLS[0]
```
And this for the fixed LLDB:
```
// (lldb) target dump section-load-list
// addr = 0x0000000000000000, section = 0x105f0a9a8: 0xfffffffffffffffd container [0x0000000000000000-0x0000000000000628) r-- 0x00000000 0x00000628 0x00000000 a.out.PT_LOAD[0]
// addr = 0x0000000000001000, section = 0x105f0adb8: 0xfffffffffffffffc container [0x0000000000001000-0x0000000000001185) r-x 0x00001000 0x00000185 0x00000000 a.out.PT_LOAD[1]
// addr = 0x0000000000002000, section = 0x105f0af48: 0xfffffffffffffffb container [0x0000000000002000-0x00000000000020cc) r-- 0x00002000 0x000000cc 0x00000000 a.out.PT_LOAD[2]
// addr = 0x0000000000003db0, section = 0x105f0b078: 0xfffffffffffffffa container [0x0000000000003db0-0x0000000000004028) rw- 0x00002db0 0x00000274 0x00000000 a.out.PT_LOAD[3]
```
We can see that previously the "PT_LOAD[3]" segment would be removed
from the section load list, and after the fix it remains and there is on
PT_TLS in the loaded sections.
Use `--match-full-lines` with FileCheck. Otherwise, the checks for `int`
and `unsigned int` will match to the fields inside two `CustomType`s and
FileCheck will start scanning from there, causing string not found
error.
Currently, LLDB prints out a rather unhelpful error message when passed
a file that it doesn't recognize as an executable.
> error: '/path/to/file' doesn't contain any 'host' platform
> architectures: arm64, armv7, armv7f, armv7k, armv7s, armv7m, armv7em,
> armv6m, armv6, armv5, armv4, arm, thumbv7, thumbv7k, thumbv7s,
> thumbv7f, thumbv7m, thumbv7em, thumbv6m, thumbv6, thumbv5, thumbv4t,
> thumb, x86_64, x86_64, arm64, arm64e
I did a quick search internally and found at least 24 instances of users
being confused by this. This patch improves the error message when it
doesn't recognize the file as an executable, but keeps the existing
error message otherwise, i.e. when it's an object file we understand,
but the current platform doesn't support.
