Commit Graph

5156 Commits

Author SHA1 Message Date
Fangrui Song 55abd2b295 [Driver] Fix multiple bugs related to dependency file options: -M -MM -MD -MMD -MT -MQ
-M -o test.i => dependency file is test.d, not test.i
-MM -o test.i => dependency file is test.d, not test.i
-M -MMD => bogus warning -Wunused-command-line-argument
-M MT dummy => -w not rendered

llvm-svn: 371918
2019-09-14 06:01:22 +00:00
Fangrui Song 6fe3d36768 [Driver] Improve Clang::getDependencyFileName and its tests after rC371853
The test file name metadata-with-dots.c is confusing because -MD and -MMD
have nothing to do with metadata.

llvm-svn: 371917
2019-09-14 04:13:15 +00:00
Luke Cheeseman ab9acda026 Fix depfile name construction
- When using -o, the provided filename is using for constructing the depfile
  name (when -MMD is passed).
- The logic looks for the rightmost '.' character and replaces what comes after
  with 'd'.
- This works incorrectly when the filename has no extension and the directories
  have '.' in them (e.g. out.dir/test)
- This replaces the funciton to just llvm::sys::path functionality

Differential Revision: https://reviews.llvm.org/D67542

llvm-svn: 371853
2019-09-13 13:15:35 +00:00
Nandor Licker 950b70dcc7 [Clang Interpreter] Initial patch for the constexpr interpreter
Summary:
This patch introduces the skeleton of the constexpr interpreter,
capable of evaluating a simple constexpr functions consisting of
if statements. The interpreter is described in more detail in the
RFC. Further patches will add more features.

Reviewers: Bigcheese, jfb, rsmith

Subscribers: bruno, uenoku, ldionne, Tyker, thegameg, tschuett, dexonsmith, mgorny, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D64146

llvm-svn: 371834
2019-09-13 09:46:16 +00:00
Richard Smith c624510f13 For PR17164: split -fno-lax-vector-conversion into three different
levels:

 -- none: no lax vector conversions [new GCC default]
 -- integer: only conversions between integer vectors [old GCC default]
 -- all: all conversions between same-size vectors [Clang default]

For now, Clang still defaults to "all" mode, but per my proposal on
cfe-dev (2019-04-10) the default will be changed to "integer" as soon as
that doesn't break lots of testcases. (Eventually I'd like to change the
default to "none" to match GCC and general sanity.)

Following GCC's behavior, the driver flag -flax-vector-conversions is
translated to -flax-vector-conversions=integer.

This reinstates r371805, reverted in r371813, with an additional fix for
lldb.

llvm-svn: 371817
2019-09-13 06:02:15 +00:00
Jonas Devlieghere 4aaa77e48d Revert "For PR17164: split -fno-lax-vector-conversion into three different"
This breaks the LLDB build. I tried reaching out to Richard, but haven't
gotten a reply yet.

llvm-svn: 371813
2019-09-13 05:16:59 +00:00
Richard Smith 49c4e58b75 For PR17164: split -fno-lax-vector-conversion into three different
levels:

 -- none: no lax vector conversions [new GCC default]
 -- integer: only conversions between integer vectors [old GCC default]
 -- all: all conversions between same-size vectors [Clang default]

For now, Clang still defaults to "all" mode, but per my proposal on
cfe-dev (2019-04-10) the default will be changed to "integer" as soon as
that doesn't break lots of testcases. (Eventually I'd like to change the
default to "none" to match GCC and general sanity.)

Following GCC's behavior, the driver flag -flax-vector-conversions is
translated to -flax-vector-conversions=integer.

llvm-svn: 371805
2019-09-13 02:20:00 +00:00
Heejin Ahn e8b2b8868d [WebAssembly] Add -fwasm-exceptions for wasm EH
Summary:
This adds `-fwasm-exceptions` (in similar fashion with
`-fdwarf-exceptions` or `-fsjlj-exceptions`) that turns on everything
with wasm exception handling from the frontend to the backend.

We currently have `-mexception-handling` in clang frontend, but this is
only about the architecture capability and does not turn on other
necessary options such as the exception model in the backend. (This can
be turned on with `llc -exception-model=wasm`, but llc is not invoked
separately as a command line tool, so this option has to be transferred
from clang.)

Turning on `-fwasm-exceptions` in clang also turns on
`-mexception-handling` if not specified, and will error out if
`-mno-exception-handling` is specified.

Reviewers: dschuff, tlively, sbc100

Subscribers: aprantl, jgravelle-google, sunfish, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D67208

llvm-svn: 371708
2019-09-12 04:01:37 +00:00
Diogo N. Sampaio 73ec745793 [ARM] Take into account -mcpu and -mfpu options while handling 'crypto' feature
Submittin in behalf of krisb (Kristina Bessonova) <ch.bessonova@gmail.com>

Summary:
'+crypto' means '+aes' and '+sha2' for arch >= ARMv8 when they were
not disabled explicitly. But this is correctly handled only in case of
'-march' option, though the feature may also be specified through
the '-mcpu' or '-mfpu' options. In the following example:

  $ clang -mcpu=cortex-a57 -mfpu=crypto-neon-fp-armv8

'aes' and 'sha2' are disabled that is quite unexpected:

  $ clang -cc1 -triple armv8--- -target-cpu cortex-a57
    <...> -target-feature -sha2 -target-feature -aes -target-feature +crypto

This exposed by https://reviews.llvm.org/D63936 that makes
the 'aes' and 'sha2' features disabled by default.

So, while handling the 'crypto' feature we need to take into account:
  - a CPU name, as it provides the information about architecture
    (if no '-march' option specified),
  - features, specified by the '-mcpu' and '-mfpu' options.

Reviewers: SjoerdMeijer, ostannard, labrinea, dnsampaio

Reviewed By: dnsampaio

Subscribers: ikudrin, javed.absar, kristof.beyls, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D66018

Author: krisb
llvm-svn: 371597
2019-09-11 09:06:17 +00:00
Adrian Prantl f987f561fa Don't emit .gnu_pubnames when tuning for LLDB.
LLDB reads the various .apple* accelerator tables (and in the near
future: the DWARF 5 accelerator tables) which should make
.gnu_pubnames redundant. This changes the Clang driver to no longer
pass -ggnu-pubnames when tuning for LLDB.

Thanks to David Blaikie for pointing this out!
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20190422/thread.html#646062

rdar://problem/50142073

Differential Revision: https://reviews.llvm.org/D67373

llvm-svn: 371530
2019-09-10 15:53:18 +00:00
Roger Ferrer Ibanez 93c4d53b0a [RISCV] Make -march=rv{32,64}gc the default in RISC-V Linux
This is the logical follow-up of D65634.

Differential Revision: https://reviews.llvm.org/D66003

llvm-svn: 371496
2019-09-10 08:16:24 +00:00
Roger Ferrer Ibanez 8e87396307 [RISCV] Default to ilp32d/lp64d in RISC-V Linux
When running clang as a native compiler in RISC-V Linux the flag
-mabi=ilp32d / -mabi=lp64d is always mandatory. This change makes it the
default there.

Differential Revision: https://reviews.llvm.org/D65634

llvm-svn: 371494
2019-09-10 07:57:36 +00:00
Roger Ferrer Ibanez 60f0a6f6ff [RISCV] Move architecture parsing code into its own function
I plan to reuse it in a later patch.

This is almost NFC except a small change in control flow when diagnosing
+d without +f.

Differential Revision: https://reviews.llvm.org/D66002

llvm-svn: 371492
2019-09-10 07:47:34 +00:00
Pirama Arumuga Nainar ff49a52cf3 [Driver] Handle default case in refactored addOpenMPRuntime
Summary:
Appease failed builds (due to -Werror and -Wswitch) where OMPRT_Unknown
is not handled in the switch statement (even though it's handled by the
early exit).

This fixes -Wswitch triggered by r371442.

Reviewers: srhines, danalbert, jdoerfert

Subscribers: guansong, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D67364

llvm-svn: 371444
2019-09-09 19:52:39 +00:00
Pirama Arumuga Nainar d60ff75b56 [Driver] Add -static-openmp driver option
Summary:
For Gnu, FreeBSD and NetBSD, this option forces linking with the static
OpenMP host runtime (similar to -static-libgcc and -static-libstdcxx).

Android's NDK will start the shared OpenMP runtime in addition to the static
libomp.  In this scenario, the linker will prefer to use the shared library by
default.  Add this option to enable linking with the static libomp.

Reviewers: Hahnfeld, danalbert, srhines, joerg, jdoerfert

Subscribers: guansong, cfe-commits

Tags: #clang

Fixes https://github.com/android-ndk/ndk/issues/1028

Differential Revision: https://reviews.llvm.org/D67200

llvm-svn: 371437
2019-09-09 18:31:41 +00:00
Hans Wennborg 999f8a7416 Revert r361885 "[Driver] Fix -working-directory issues"
This made clang unable to open files using relative paths on network shares on
Windows (PR43204). On the bug it was pointed out that createPhysicalFileSystem()
is not terribly mature, and using it is risky. Reverting for now until there's
a clear way forward.

> Currently the `-working-directory` option does not actually impact the working
> directory for all of the clang driver, it only impacts how files are looked up
> to make sure they exist.  This means that that clang passes the wrong paths
> to -fdebug-compilation-dir and -coverage-notes-file.
>
> This patch fixes that by changing all the places in the driver where we convert
> to absolute paths to use the VFS, and then calling setCurrentWorkingDirectory on
> the VFS.  This also changes the default VFS for `Driver` to use a virtualized
> working directory, instead of changing the process's working directory.
>
> Differential Revision: https://reviews.llvm.org/D62271

This also revertes the part of r369938 which checked that -working-directory works.

llvm-svn: 371027
2019-09-05 08:43:00 +00:00
Ilya Biryukov 433927595d [Driver] Use shared singleton instance of DriverOptTable
Summary:
This significantly reduces the time required to run clangd tests, by
~10%.

Should also have an effect on other tests that run command-line parsing
multiple times inside a single invocation.

Reviewers: gribozavr, sammccall

Reviewed By: sammccall

Subscribers: kadircet, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D67163

llvm-svn: 370908
2019-09-04 14:26:28 +00:00
Roman Lebedev 2c9f83cfab Revert "[Clang Interpreter] Initial patch for the constexpr interpreter"
Breaks BUILD_SHARED_LIBS build, introduces cycles in library dependency
graphs. (clangInterp depends on clangAST which depends on clangInterp)

This reverts r370839, which is an yet another recommit of D64146.

llvm-svn: 370874
2019-09-04 10:57:06 +00:00
Nandor Licker 32f82c9cba [Clang Interpreter] Initial patch for the constexpr interpreter
Summary:
This patch introduces the skeleton of the constexpr interpreter,
capable of evaluating a simple constexpr functions consisting of
if statements. The interpreter is described in more detail in the
RFC. Further patches will add more features.

Reviewers: Bigcheese, jfb, rsmith

Subscribers: bruno, uenoku, ldionne, Tyker, thegameg, tschuett, dexonsmith, mgorny, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D64146

llvm-svn: 370839
2019-09-04 05:49:41 +00:00
Ed Maste dfde7b09c8 clang: default to DWARF 4 for FreeBSD 12.0 and later
Older FreeBSD versions included GDB 6.1 and had other tools that were
unable to handle debug information newer than DWARF 2.  Those tools have
since been updated.  (An old version of GDB is still kept for kernel
crash handling, but the kernel is compiled with an explicit -gdwarf2.)

Reviewed by:	dim
Differential Revision:	https://reviews.llvm.org/D66760

llvm-svn: 370779
2019-09-03 16:30:21 +00:00
Nandor Licker c3bdad8c1e Revert [Clang Interpreter] Initial patch for the constexpr interpreter
This reverts r370636 (git commit 8327fed947)

llvm-svn: 370642
2019-09-02 11:34:47 +00:00
Nandor Licker 8327fed947 [Clang Interpreter] Initial patch for the constexpr interpreter
Summary:
This patch introduces the skeleton of the constexpr interpreter,
capable of evaluating a simple constexpr functions consisting of
if statements. The interpreter is described in more detail in the
RFC. Further patches will add more features.

Reviewers: Bigcheese, jfb, rsmith

Subscribers: bruno, uenoku, ldionne, Tyker, thegameg, tschuett, dexonsmith, mgorny, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D64146

llvm-svn: 370636
2019-09-02 10:38:08 +00:00
Nandor Licker a6bef738bf Revert [Clang Interpreter] Initial patch for the constexpr interpreter
This reverts r370584 (git commit afcb3de117)

llvm-svn: 370588
2019-08-31 15:15:39 +00:00
Nandor Licker afcb3de117 [Clang Interpreter] Initial patch for the constexpr interpreter
Summary:
This patch introduces the skeleton of the constexpr interpreter,
capable of evaluating a simple constexpr functions consisting of
if statements. The interpreter is described in more detail in the
RFC. Further patches will add more features.

Reviewers: Bigcheese, jfb, rsmith

Subscribers: bruno, uenoku, ldionne, Tyker, thegameg, tschuett, dexonsmith, mgorny, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D64146

llvm-svn: 370584
2019-08-31 15:00:38 +00:00
Nandor Licker 0300c3536a Revert [Clang Interpreter] Initial patch for the constexpr interpreter
This reverts r370531 (git commit d4c1002e0b)

llvm-svn: 370535
2019-08-30 21:32:00 +00:00
Nandor Licker d4c1002e0b [Clang Interpreter] Initial patch for the constexpr interpreter
Summary:
This patch introduces the skeleton of the constexpr interpreter,
capable of evaluating a simple constexpr functions consisting of
if statements. The interpreter is described in more detail in the
RFC. Further patches will add more features.

Reviewers: Bigcheese, jfb, rsmith

Subscribers: bruno, uenoku, ldionne, Tyker, thegameg, tschuett, dexonsmith, mgorny, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D64146

llvm-svn: 370531
2019-08-30 21:17:03 +00:00
Nandor Licker 5c8b94a672 Revert [Clang Interpreter] Initial patch for the constexpr interpreter
This reverts r370476 (git commit a559095054)

llvm-svn: 370481
2019-08-30 15:41:45 +00:00
Nandor Licker a559095054 [Clang Interpreter] Initial patch for the constexpr interpreter
Summary:
This patch introduces the skeleton of the constexpr interpreter,
capable of evaluating a simple constexpr functions consisting of
if statements. The interpreter is described in more detail in the
RFC. Further patches will add more features.

Reviewers: Bigcheese, jfb, rsmith

Subscribers: bruno, uenoku, ldionne, Tyker, thegameg, tschuett, dexonsmith, mgorny, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D64146

llvm-svn: 370476
2019-08-30 15:02:09 +00:00
Alex Lorenz 3737c0239a [driver][xray] fix the macOS support checker by supporting -macos
triple in addition to -darwin

The previous check incorrectly checked for macOS support by
allowing -darwin triples only, and -macos triple was not supported.

Differential Revision: https://reviews.llvm.org/D61758

llvm-svn: 370093
2019-08-27 18:26:36 +00:00
Alex Lorenz 8679ef4e46 [driver] add a new option `-gen-cdb-fragment-path` to emit
a fragment of a compilation database for each compilation

This patch adds a new option called -gen-cdb-fragment-path to the driver,
which can be used to specify a directory path to which clang can emit a fragment
of a CDB for each compilation it needs to invoke.

This option emits the same CDB contents as -MJ, and will be ignored if -MJ is specified.

Differential Revision: https://reviews.llvm.org/D66555

llvm-svn: 369938
2019-08-26 17:59:41 +00:00
Erich Keane e30b71f9dc Fix -dA flag, it is not a preprocessor flag.
-dA was in the d_group, which is a preprocessor state dumping group.
However -dA is a debug flag to cause a verbose asm.  It was already
implemented to do the same thing as -fverbose-asm, so make it just be an
alias.

llvm-svn: 369926
2019-08-26 17:00:13 +00:00
Puyan Lotfi 926f4f76c3 [clang][ifs] Dropping older experimental interface stub formats.
I've been working on a new tool, llvm-ifs, for merging interface stub files
generated by clang and I've iterated on my derivative format of TBE to a newer
format. llvm-ifs will only support the new format, so I am going to drop the
older experimental interface stubs formats in this commit to make things
simpler.

Differential Revision: https://reviews.llvm.org/D66573

llvm-svn: 369719
2019-08-22 23:44:34 +00:00
Puyan Lotfi d24184591f [clang][ifs] New interface stubs format (llvm triple based).
After posting llvm-ifs on phabricator, I made some progress in hardening up how
I think the format for Interface Stubs should look. There are a number of
things I think the TBE format was missing (no endianness, no info about the
Object Format because it assumes ELF), so I have added those and broken off
from being as similar to the TBE schema. In a subsequent commit I can drop the
other formats.

An example of how The format will look is as follows:

--- !experimental-ifs-v1
IfsVersion: 1.0
Triple: x86_64-unknown-linux-gnu
ObjectFileFormat: ELF
Symbols:
  _Z9nothiddenv: { Type: Func }
  _Z10cmdVisiblev: { Type: Func }
...

The format is still marked experimental.

Differential Revision: https://reviews.llvm.org/D66446

llvm-svn: 369715
2019-08-22 23:29:22 +00:00
Hans Wennborg 8288453f6a Revert r369402 "win: Enable /Zc:twoPhase by default if targeting MSVC 2017 update 3 or newer"
This broke compiling some ASan tests with never versions of MSVC/the Win
SDK, see https://crbug.com/996675

> MSVC 2017 update 3 (_MSC_VER 1911) enables /Zc:twoPhase by default, and
> so should clang-cl:
> https://docs.microsoft.com/en-us/cpp/build/reference/zc-twophase
>
> clang-cl takes the MSVC version it emulates from the -fmsc-version flag,
> or if that's not passed it tries to check what the installed version of
> MSVC is and uses that, and failing that it uses a default version that's
> currently 1911. So this changes the default if no -fmsc-version flag is
> passed and no installed MSVC is detected. (It also changes the default
> if -fmsc-version is passed or MSVC is detected, and either indicates
> _MSC_VER >= 1911.)
>
> As mentioned in the MSDN article, the Windows SDK header files in
> version 10.0.15063.0 (Creators Update or Redstone 2) and earlier
> versions do not work correctly with /Zc:twoPhase. If you need to use
> these old SDKs with a new clang-cl, explicitly pass /Zc:twoPhase- to get
> the old behavior.
>
> Fixes PR43032.
>
> Differential Revision: https://reviews.llvm.org/D66394

llvm-svn: 369647
2019-08-22 13:15:36 +00:00
Nico Weber fe91b9d6da win: Enable /Zc:twoPhase by default if targeting MSVC 2017 update 3 or newer
MSVC 2017 update 3 (_MSC_VER 1911) enables /Zc:twoPhase by default, and
so should clang-cl:
https://docs.microsoft.com/en-us/cpp/build/reference/zc-twophase

clang-cl takes the MSVC version it emulates from the -fmsc-version flag,
or if that's not passed it tries to check what the installed version of
MSVC is and uses that, and failing that it uses a default version that's
currently 1911. So this changes the default if no -fmsc-version flag is
passed and no installed MSVC is detected. (It also changes the default
if -fmsc-version is passed or MSVC is detected, and either indicates
_MSC_VER >= 1911.)

As mentioned in the MSDN article, the Windows SDK header files in
version 10.0.15063.0 (Creators Update or Redstone 2) and earlier
versions do not work correctly with /Zc:twoPhase. If you need to use
these old SDKs with a new clang-cl, explicitly pass /Zc:twoPhase- to get
the old behavior.

Fixes PR43032.

Differential Revision: https://reviews.llvm.org/D66394

llvm-svn: 369402
2019-08-20 16:28:11 +00:00
Troy A. Johnson c0d70bca0f [X86] Support -mlong-double-80
Add an option group for all of the -mlong-double-* options and make
-mlong-double-80 restore the default long double behavior for X86.  The
motivations are that GNU accepts the -mlong-double-80 option and that complex
Makefiles often need a way of undoing earlier options. Prior to this commit, if
one chooses 64-bit or 128-bit long double for X86, there is no way to undo that
choice and restore the 80-bit behavior.

Differential Revision: https://reviews.llvm.org/D66055

llvm-svn: 369183
2019-08-17 04:20:24 +00:00
Troy A. Johnson 0dd9494d47 Revert "[X86] Support -mlong-double-80"
This reverts commit 250aafa2c4.
Caused buildbot failures -- still investigating.

llvm-svn: 369170
2019-08-16 23:18:22 +00:00
Troy A. Johnson 250aafa2c4 [X86] Support -mlong-double-80
Add an option group for all of the -mlong-double-* options and make
-mlong-double-80 restore the default long double behavior for X86.  The
motivations are that GNU accepts the -mlong-double-80 option and that complex
Makefiles often need a way of undoing earlier options. Prior to this commit, if
one chooses 64-bit or 128-bit long double for X86, there is no way to undo that
choice and restore the 80-bit behavior.

Differential Revision: https://reviews.llvm.org/D66055

llvm-svn: 369152
2019-08-16 21:00:22 +00:00
Jonas Devlieghere 2b3d49b610 [Clang] Migrate llvm::make_unique to std::make_unique
Now that we've moved to C++14, we no longer need the llvm::make_unique
implementation from STLExtras.h. This patch is a mechanical replacement
of (hopefully) all the llvm::make_unique instances across the monorepo.

Differential revision: https://reviews.llvm.org/D66259

llvm-svn: 368942
2019-08-14 23:04:18 +00:00
Puyan Lotfi 740f69b91b [NFC][clang] Moving argument handling: Driver::BuildActions -> handleArguments
This patch simply moves code that already exists into a new function.
Specifically I think it will make the BuildActions code for building a clang
job pipeline easier to read and work with.

Differential Revision: https://reviews.llvm.org/D66058

llvm-svn: 368881
2019-08-14 17:02:21 +00:00
Sven van Haastregt 15e26d1fe9 Fix _WIN32 / _WIN64 Wundef warnings
For these macros it is the definedness that matters rather than
the value.  Make new uses of these macros consistent with existing
uses.

llvm-svn: 368822
2019-08-14 10:30:18 +00:00
Puyan Lotfi e5ade767e5 [NFC][clang] Adding argument based Phase list filtering to getComplicationPhases
This patch removes usage of FinalPhase from anywhere outside of the scope where
it is used to do argument handling.  It also adds argument based trimming of
the Phase list pulled out of the Types.def table.

Differential Revision: https://reviews.llvm.org/D65993

llvm-svn: 368734
2019-08-13 18:42:03 +00:00
Nico Weber 2346b92f2b clang: Don't warn on unused momit-leaf-frame-pointer when frame pointers are off.
This fixes a regression from r365860: As that commit message
states, there are 3 valid states targeted by the combination of
-f(no-)omit-frame-pointer and -m(no-)omit-leaf-frame-pointer.

After r365860 it's impossible to get from state 10 (omit just
leaf frame pointers) to state 11 (omit all frame pointers)
in a single command line without getting a warning.

This change restores that functionality.

Fixes PR42966.

Differential Revision: https://reviews.llvm.org/D66142

llvm-svn: 368728
2019-08-13 17:37:09 +00:00
Momchil Velikov 941660299a Enable memtag sanitizer in all AArch64 toolchains
That sanitizer does not have runtime library or other dependencies.

Differential Revision: https://reviews.llvm.org/D65642

llvm-svn: 368697
2019-08-13 14:20:23 +00:00
Momchil Velikov 5b25674b73 [AArch64] Make the memtag sanitizer require the memtag extension
... or otherwise we get an ICE.

Differential Revision: https://reviews.llvm.org/D65508

llvm-svn: 368696
2019-08-13 14:20:06 +00:00
Peter Collingbourne 0e497d1554 cfi-icall: Allow the jump table to be optionally made non-canonical.
The default behavior of Clang's indirect function call checker will replace
the address of each CFI-checked function in the output file's symbol table
with the address of a jump table entry which will pass CFI checks. We refer
to this as making the jump table `canonical`. This property allows code that
was not compiled with ``-fsanitize=cfi-icall`` to take a CFI-valid address
of a function, but it comes with a couple of caveats that are especially
relevant for users of cross-DSO CFI:

- There is a performance and code size overhead associated with each
  exported function, because each such function must have an associated
  jump table entry, which must be emitted even in the common case where the
  function is never address-taken anywhere in the program, and must be used
  even for direct calls between DSOs, in addition to the PLT overhead.

- There is no good way to take a CFI-valid address of a function written in
  assembly or a language not supported by Clang. The reason is that the code
  generator would need to insert a jump table in order to form a CFI-valid
  address for assembly functions, but there is no way in general for the
  code generator to determine the language of the function. This may be
  possible with LTO in the intra-DSO case, but in the cross-DSO case the only
  information available is the function declaration. One possible solution
  is to add a C wrapper for each assembly function, but these wrappers can
  present a significant maintenance burden for heavy users of assembly in
  addition to adding runtime overhead.

For these reasons, we provide the option of making the jump table non-canonical
with the flag ``-fno-sanitize-cfi-canonical-jump-tables``. When the jump
table is made non-canonical, symbol table entries point directly to the
function body. Any instances of a function's address being taken in C will
be replaced with a jump table address.

This scheme does have its own caveats, however. It does end up breaking
function address equality more aggressively than the default behavior,
especially in cross-DSO mode which normally preserves function address
equality entirely.

Furthermore, it is occasionally necessary for code not compiled with
``-fsanitize=cfi-icall`` to take a function address that is valid
for CFI. For example, this is necessary when a function's address
is taken by assembly code and then called by CFI-checking C code. The
``__attribute__((cfi_jump_table_canonical))`` attribute may be used to make
the jump table entry of a specific function canonical so that the external
code will end up taking a address for the function that will pass CFI checks.

Fixes PR41972.

Differential Revision: https://reviews.llvm.org/D65629

llvm-svn: 368495
2019-08-09 22:31:59 +00:00
Puyan Lotfi 82c51b18e4 [clang][NFC] Consolidating usage of "FinalPhase" in Driver::BuildActions.
I am working to remove this concept of the "FinalPhase" in the clang driver,
but it is used in a lot of different places to do argument handling for
different combinations of phase pipelines and arguments. I am trying to
consolidate most of the uses of "FinalPhase" into its own separate scope.
Eventually, in a subsequent patch I will move all of this stuff to a separate
function, and have more of the complication phase list construction setup into
types::getComplicationPhases.

Differential Revision: https://reviews.llvm.org/D65969

llvm-svn: 368393
2019-08-09 04:55:09 +00:00
Brian Cain 7b953b6455 [clang] Add no-warn support for Wa
llvm-svn: 368328
2019-08-08 19:19:20 +00:00
Fangrui Song 7dbdc8de18 [Driver] Move LIBRARY_PATH before user inputs
Fixes PR16786

Currently, library paths specified by LIBRARY_PATH are placed after inputs: `inputs LIBRARY_PATH stdlib`
In gcc, the order is: `LIBRARY_PATH inputs stdlib` if not cross compiling.
(On Darwin targets, isCrossCompiling() always returns false.)

This patch changes the behavior to match gcc.

Reviewed By: hfinkel

Differential Revision: https://reviews.llvm.org/D65880

llvm-svn: 368245
2019-08-08 01:55:27 +00:00
Roger Ferrer Ibanez 371bdc9b7f [RISCV] Remove duplicated logic when determining the target ABI
We were calculating twice ilp32/lp64. Do this in one place instead.

Differential Revision: https://reviews.llvm.org/D48357

llvm-svn: 368128
2019-08-07 07:08:00 +00:00