This relands commit 7313474319.
It failed on Windows/Mac because `-fjmc` is only checked for ELF targets.
Check the flag unconditionally instead and issue a warning for non-ELF targets.
The motivation is to enable the MSVC-style JMC instrumentation usable by a ELF-based
debugger. Since there is no prior experience implementing JMC feature for ELF-based
debugger, it might be better to just reuse existing MSVC-style JMC instrumentation.
For debuggers that support both ELF&COFF (like lldb), the JMC implementation might
be shared between ELF&COFF. If this is found to inadequate, it is pretty low-cost
switching to alternatives.
Implementation:
- The '-fjmc' is already a driver and cc1 flag. Wire it up for ELF in the driver.
- Refactor the JMC instrumentation pass a little bit.
- The ELF handling is different from MSVC in two places:
* the flag section name is ".just.my.code" instead of ".msvcjmc"
* the way default function is provided: MSVC uses /alternatename; ELF uses weak function.
Based on D118428.
Reviewed By: rnk
Differential Revision: https://reviews.llvm.org/D119910
The introduction and some examples are on this page:
https://devblogs.microsoft.com/cppblog/announcing-jmc-stepping-in-visual-studio/
The `/JMC` flag enables these instrumentations:
- Insert at the beginning of every function immediately after the prologue with
a call to `void __fastcall __CheckForDebuggerJustMyCode(unsigned char *JMC_flag)`.
The argument for `__CheckForDebuggerJustMyCode` is the address of a boolean
global variable (the global variable is initialized to 1) with the name
convention `__<hash>_<filename>`. All such global variables are placed in
the `.msvcjmc` section.
- The `<hash>` part of `__<hash>_<filename>` has a one-to-one mapping
with a directory path. MSVC uses some unknown hashing function. Here I
used DJB.
- Add a dummy/empty COMDAT function `__JustMyCode_Default`.
- Add `/alternatename:__CheckForDebuggerJustMyCode=__JustMyCode_Default` link
option via ".drectve" section. This is to prevent failure in
case `__CheckForDebuggerJustMyCode` is not provided during linking.
Implementation:
All the instrumentations are implemented in an IR codegen pass. The pass is placed immediately before CodeGenPrepare pass. This is to not interfere with mid-end optimizations and make the instrumentation target-independent (I'm still working on an ELF port in a separate patch).
Reviewed By: hans
Differential Revision: https://reviews.llvm.org/D118428
we already accept "--target=". No reason to not accept "-target" too
(that's the one I typically use for some reason).
Differential revision: https://reviews.llvm.org/D119446
A significant number of our tests in C accidentally use functions
without prototypes. This patch converts the function signatures to have
a prototype for the situations where the test is not specific to K&R C
declarations. e.g.,
void func();
becomes
void func(void);
This is the sixth batch of tests being updated (there are a significant
number of other tests left to be updated).
clang-cl MSVC required version is 19.20 now. Update the default
-fms-compatibility-version to 19.14.
Differential Revision: https://reviews.llvm.org/D114639
This patch adds support for the MSVC /HOTPATCH flag: https://docs.microsoft.com/sv-se/cpp/build/reference/hotpatch-create-hotpatchable-image?view=msvc-170&viewFallbackFrom=vs-2019
The flag is translated to a new -fms-hotpatch flag, which in turn adds a 'patchable-function' attribute for each function in the TU. This is then picked up by the PatchableFunction pass which would generate a TargetOpcode::PATCHABLE_OP of minsize = 2 (which means the target instruction must resolve to at least two bytes). TargetOpcode::PATCHABLE_OP is only implemented for x86/x64. When targetting ARM/ARM64, /HOTPATCH isn't required (instructions are always 2/4 bytes and suitable for hotpatching).
Additionally, when using /Z7, we generate a 'hot patchable' flag in the CodeView debug stream, in the S_COMPILE3 record. This flag is then picked up by LLD (or link.exe) and is used in conjunction with the linker /FUNCTIONPADMIN flag to generate extra space before each function, to accommodate for live patching long jumps. Please see: d703b92296/lld/COFF/Writer.cpp (L1298)
The outcome is that we can finally use Live++ or Recode along with clang-cl.
NOTE: It seems that MSVC cl.exe always enables /HOTPATCH on x64 by default, although if we did the same I thought we might generate sub-optimal code (if this flag was active by default). Additionally, MSVC always generates a .debug$S section and a S_COMPILE3 record, which Clang doesn't do without /Z7. Therefore, the following MSVC command-line "cl /c file.cpp" would have to be written with Clang such as "clang-cl /c file.cpp /HOTPATCH /Z7" in order to obtain the same result.
Depends on D43002, D80833 and D81301 for the full feature.
Differential Revision: https://reviews.llvm.org/D116511
clang-cl maps /wdNNNN to -Wno-flags for a few warnings that map
cleanly from cl.exe concepts to clang concepts.
This patch adds support for the same numbers to
`#pragma warning(disable : NNNN)`. It also lets
`#pragma warning(push)` and `#pragma warning(pop)` have an effect,
since these are used together with `warning(disable)`.
The optional numeric argument to `warning(push)` is ignored,
as are the other non-`disable` `pragma warning()` arguments.
(Supporting `error` would be easy, but we also don't support
`/we`, and those should probably be added together.)
The motivating example is that a bunch of code (including in LLVM)
uses this idiom to locally disable warnings about calls to deprecated
functions in Windows-only code, and 4996 maps nicely to
-Wno-deprecated-declarations:
#pragma warning(push)
#pragma warning(disable: 4996)
f();
#pragma warning(pop)
Implementation-wise:
- Move `/wd` flag handling from Options.td to actual Driver-level code
- Extract the function mapping cl.exe IDs to warning groups to the
new file clang/lib/Basic/CLWarnings.cpp
- Create a diag::Group enum so that CLWarnings.cpp can refer to
existing groups by ID (and give DllexportExplicitInstantiationDecl
a named group), and add a function to map a diag::Group to the
spelling of it's associated commandline flag
- Call that new function from PragmaWarningHandler
Differential Revision: https://reviews.llvm.org/D110668
Clang diagnostics should not start with a capital letter or use
trailing punctuation (https://clang.llvm.org/docs/InternalsManual.html#the-format-string),
but quite a few driver diagnostics were not following this advice. This
corrects the grammar and punctuation to improve consistency, but does
not change the circumstances under which the diagnostics are produced.
I don't know how well this works with clang-cl, but people want to try
it out, and I think we want to make it work, so exposing the flags seems
reasonable.
Differential revision: https://reviews.llvm.org/D106791
Constructor homing reduces the amount of class type info that is emitted
by emitting conmplete type info for a class only when a constructor for
that class is emitted.
This will mainly reduce the amount of duplicate debug info in object
files. In Chrome enabling ctor homing decreased total build directory sizes
by about 30%.
It's also expected that some class types (such as unused classes)
will no longer be emitted in the debug info. This is fine, since we wouldn't
expect to need these types when debugging.
In some cases (e.g. libc++, https://reviews.llvm.org/D98750), classes
are used without calling the constructor. Since this is technically
undefined behavior, enabling constructor homing should be fine.
However Clang now has an attribute
`__attribute__((standalone_debug))` that can be used on classes to
ignore ctor homing.
Bug: https://bugs.llvm.org/show_bug.cgi?id=46537
Differential Revision: https://reviews.llvm.org/D106084
This patch does three things:
- Map the /external:I flag to -isystem
- Add support for the /external:env:<var> flag which reads system
include paths from the <var> environment variable
- Pick up system include dirs EXTERNAL_INCLUDE in addition to the old
INCLUDE environment variable.
Differential revision: https://reviews.llvm.org/D104387
Also:
- add driver test (fsanitize-use-after-return.c)
- add basic IR test (asan-use-after-return.cpp)
- (NFC) cleaned up logic for generating table of __asan_stack_malloc
depending on flag.
for issue: https://github.com/google/sanitizers/issues/1394
Reviewed By: vitalybuka
Differential Revision: https://reviews.llvm.org/D104076
They are still unsupported, but at least this makes clang-cl not mistake
them for being filenames.
As pointed out in the bug, VS 16.10 now uses these flags in new projects
by default.
VS 2019 16.11 (just released in Preview) is adding support for the
/std:c++20 option and bumping /std:c++latest to "post-c++20". This
updates clang-cl to match.
Differential revision: https://reviews.llvm.org/D103155
MSVC has added some new flags. Although they're not supported, this adds
parsing support for them so clang-cl doesn't treat them as filenames.
Except for /fsanitize=address which we do support. (clang-cl already
exposes the -fsanitize= option, but this allows using the
MSVC-spelling with a slash.)
Differential revision: https://reviews.llvm.org/D101439
Currently, support for the x32 ABI is handled as a multilib to the
x86_64 target only. However, full self-hosting x32 systems treating it
as a separate architecture with its own architecture triplets as well as
search paths exist as well, in Debian's x32 port and elsewhere.
This adds the missing architecture triplets and search paths so that
clang can work as a native compiler on x32, and updates the tests so
that they pass when using an x32 libdir suffix.
Additionally, we would previously also assume that objects from any
x86_64-linux-gnu GCC installation could be used to target x32. This
changes the logic so that only GCC installations that include x32
support are used when targetting x32, meaning x86_64-linux-gnux32 GCC
installations, and x86_64-linux-gnu and i686-linux-gnu GCC installations
that include x32 multilib support.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D52050
On clang emits the compiler version string into debug information
by default for both dwarf and codeview. That makes compiler output
needlessly compiler-version-dependent which makes e.g. comparing
object file outputs during a bisect hard. So it's nice if there's
an easy way to turn this off.
(On ELF, this flag also controls the .comment section, but that
part is ELF-only. The debug-info bit isn't.)
Differential Revision: https://reviews.llvm.org/D97695
When targeting a MSVC triple, --dependant-libs with the name of the clang runtime library for profiling is added to the command line args. In it's current implementations clang_rt.profile-<ARCH> is chosen as the name. When building a distribution using LLVM_ENABLE_PER_TARGET_RUNTIME_DIR this fails, due to the runtime file names not having an architecture suffix in the filename.
This patch refactors getCompilerRT and getCompilerRTBasename to always consider per-target runtime directories. getCompilerRTBasename now simply returns the filename component of the path found by getCompilerRT
Differential Revision: https://reviews.llvm.org/D96638
clang-cl already defaults to C17 for .c files, but no harm
in accepting these flags. Fixes PR48185.
Differential Revision: https://reviews.llvm.org/D95575
llvmArchToWindowsSDKArch() returns "" for non-intel non-arm archs.
We're checking for "/fake/lib/" which is followed by the result
of that function -- but if that returns an empty string, then that
trailing slash isn't there. As fix, just explicitly pass a triple
that's intel or arm (I randomly chose aarch64). Since the test runs
with -###, that arch doesn't have to be in LLVM_TARGETS_TO_BUILD.
These do for the Windows SDK path what D85998 did for
%VCToolsInstallDir% with /vctoolsdir: Offer a way to set them with an
explicit commandline switch.
With this (and /vctoolsdir), it's possible to compile and link
against hermetic vctools and winsdk directories with:
out/gn/bin/clang-cl win.c -fuse-ld=lld \
/vctoolsdir path/to/VC/Tools/MSVC/14.26.28801 \
/winsdkdir path/to/win_sdk
compared to a long list of -imsvc and /link /libpath: flags.
While here:
- Change the case of the "Include" folder inside the windows sdk
from "include" to "Include" to match on-disk case. Since the
Windows file system is case-insensitive this isn't a behavior
change, it's just a bit cleaner.
- Add libpath tests to the /vctoolsdir
- Add a FIXME about reading env vars for win sdk and ucrt sdk
if these flags aren't present, to match the VCToolsInstallDir
logic
We should also cache all these computed paths in the driver instead
of computing them every time they're queried, but that's for a future
patch.
It'd also be nice to invent a /winsysroot: flag that sets both
/vctoolsdir: and /winsdkdir: to some well-known subdirectory.
That's for a future patch as well.
Differential Revision: https://reviews.llvm.org/D95472
cl.exe doesn't understand Zd (in either MSVC 2017 or 2019), so neiter
should we. It used to do the same as `-gline-tables-only` which is
exposed as clang-cl flag as well, so if you want this behavior, use
`gline-tables-only`. That makes it clear that it's a clang-cl-only flag
that won't work with cl.exe.
Motivated by the discussion in D92958.
Differential Revision: https://reviews.llvm.org/D93458
Add an option to directly specify where the msvc toolchain lives for
clang-cl and avoid unwanted file and registry probes.
Differential revision: https://reviews.llvm.org/D85998
Some compiler-rt tests check for the presence of the compiler accepting
-fno-lto to add that flag. Otherwise some tests don't link due to
-flto mismatch between compiling and linking.
$ cmake ... -DLLVM_ENABLE_LTO=Thin ...
$ ninja projects/compiler-rt/lib/sanitizer_common/tests/Sanitizer-x86_64-Test.exe
previously failed, now links.
Reviewed By: hans
Differential Revision: https://reviews.llvm.org/D85252
Summary:
-debug-info-kind=constructor reduces the amount of class debug info that
is emitted; this patch switches to using this as the default.
Constructor homing emits the complete type info for a class only when the
constructor is emitted, so it is expected that there will be some classes that
are not defined in the debug info anymore because they are never constructed,
and we shouldn't need debug info for these classes.
I compared the PDB files for clang, and there are 273 class types that are defined with `=limited`
but not with `=constructor` (out of ~60,000 total class types).
We've looked at a number of the types that are no longer defined with =constructor. The vast
majority of cases are something like class A is used as a parameter in a member function of
some other class B, which is emitted. But the function that uses class A is never called, and class A
is never constructed, and therefore isn't emitted in the debug info.
Bug: https://bugs.llvm.org/show_bug.cgi?id=46537
Subscribers: aprantl, cfe-commits, lldb-commits
Tags: #clang, #lldb
Differential Revision: https://reviews.llvm.org/D79147
Making -g[no-]column-info opt out reduces the length of a typical CC1 command line.
Additionally, in a non-debug compile, we won't see -dwarf-column-info.
Prior to this change, for a few compiler-rt libraries such as ubsan and
the profile library, Clang would embed "-defaultlib:path/to/rt-arch.lib"
into the .drective section of every object compiled with
-finstr-profile-generate or -fsanitize=ubsan as appropriate.
These paths assume that the link step will run from the same working
directory as the compile step. There is also evidence that sometimes the
paths become absolute, such as when clang is run from a different drive
letter from the current working directory. This is fragile, and I'd like
to get away from having paths embedded in the object if possible. Long
ago it was suggested that we use this for ASan, and apparently I felt
the same way back then:
https://reviews.llvm.org/D4428#56536
This is also consistent with how all other autolinking usage works for
PS4, Mac, and Windows: they all use basenames, not paths.
To keep things working for people using the standard GCC driver
workflow, the driver now adds the resource directory to the linker
library search path when it calls the linker. This is enough to make
check-ubsan pass, and seems like a generally good thing.
Users that invoke the linker directly (most clang-cl users) will have to
add clang's resource library directory to their linker search path in
their build system. I'm not sure where I can document this. Ideally I'd
also do it in the MSBuild files, but I can't figure out where they go.
I'd like to start with this for now.
Reviewed By: hans
Differential Revision: https://reviews.llvm.org/D65543
Yuanfang Chen