Commit Graph

786 Commits

Author SHA1 Message Date
Nikita Popov
45067d1a74 [Bitcode] Convert tests to opaque pointers (NFC) 2022-12-19 11:23:17 +01:00
Qiu Chaofan
a40ef656d8 [Intrinsic] Rename flt.rounds intrinsic to get.rounding
Address the inconsistency between FLT_ROUNDS_ and SET_ROUNDING SDAG
node. Rename FLT_ROUNDS_ to GET_ROUNDING and add llvm.get.rounding
intrinsic to replace flt.rounds.

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D139507
2022-12-19 15:22:39 +08:00
Nikita Popov
e45cf47923 [Bitcode] Remove auto-detection for typed pointers
Always read bitcode according to the -opaque-pointers mode. Do not
perform auto-detection to implicitly switch to typed pointers.

This is a step towards removing typed pointer support, and also
eliminates the class of problems where linking may fail if a typed
pointer module is loaded before an opaque pointer module. (The
latest place where this was encountered is D139924, but this has
previously been fixed in other places doing bitcode linking as well.)

Differential Revision: https://reviews.llvm.org/D139940
2022-12-14 13:38:20 +01:00
Nikita Popov
23c947d316 [Bitcode] Convert test to opaque pointers (NFC) 2022-12-13 13:02:40 +01:00
Nikita Popov
40c0d076c0 [Bitcode] Convert test to opaque pointers (NFC) 2022-12-13 12:24:05 +01:00
Nikita Popov
7a38c697ca [Bitcode] Update test to use opaque pointers (NFC) 2022-12-13 12:16:22 +01:00
Roman Lebedev
6890a26974 [NFC] Port all Bitcode tests to -passes= syntax 2022-12-09 01:04:45 +03:00
Roman Lebedev
b1a9584818 [opt] Disincentivize new tests from using old pass syntax
Over the past day or so, i've took a large swing at our tests,
and reduced the number of tests that were still using the old syntax
from ~1800 to just 200.

Left to handle: (as it is seen in this patch)
* Transforms/LSR
* Transforms/CGP
* Transforms/TypePromotion
* Transforms/HardwareLoops
* Analysis/*
* some misc.

I think this is the right point to start actively refusing
to honor the old syntax, except for the old tests,
to prevent the old syntax from creeping back in.

Thus, let's add temporary default-off flag,
and if it is not passed refuse to accept old syntax.
The tests that still need porting are annotated with this flag.

Reviewed By: aeubanks

Differential Revision: https://reviews.llvm.org/D139647
2022-12-08 23:54:03 +03:00
Johannes Doerfert
f6e3a89cc0 [AMDGPU] Annotate the intrinsics to be default and nocallback
Differential Revision: https://reviews.llvm.org/D135155
2022-12-07 14:25:25 -08:00
Alex Richardson
9114ac67a9 Overload all llvm.annotation intrinsics for globals argument
The global constant arguments could be in a different address space
than the first argument, so we have to add another overloaded argument.
This patch was originally made for CHERI LLVM (where globals can be in
address space 200), but it also appears to be useful for in-tree targets
as can be seen from the test diffs.

Differential Revision: https://reviews.llvm.org/D138722
2022-12-07 18:29:18 +00:00
Alex Richardson
e114979dce Add a baseline test for llvm.annotation IR upgrade
This will be overloaded in the next commit.
2022-12-07 18:29:18 +00:00
David Sherwood
bfb6f47e9e [SVE] Change some bfloat lane intrinsics to use i32 immediates
Almost all of the other SVE LLVM IR intrinsics take i32 values
for lane indices or other immediates. We should bring the bfloat
intrinsics in line with that. It will also make it easier to
add support for the SVE2.1 float intrinsics in future, since
they reuse the same underlying instruction classes.

I've maintained backwards compatibility with the old i64 variants
and used the autoupgrade mechanism.

Differential Revision: https://reviews.llvm.org/D138788
2022-12-07 09:19:54 +00:00
Matt Arsenault
a74c5707be Fix some test files with executable permissions 2022-12-02 17:12:03 -05:00
Alexander Shaposhnikov
f102fe7304 Revert "Revert "[opt][clang] Enable using -module-summary/-flto=thin with -S/-emit-llvm""
This reverts commit 7f608a2497
and removes the dependency of Object on IRPrinter.
2022-11-18 08:58:31 +00:00
Mikhail Goncharov
7f608a2497 Revert "[opt][clang] Enable using -module-summary/-flto=thin with -S/-emit-llvm"
This reverts commit 34ab474348.

as it has introduced circular dependency lib - analysis
2022-11-18 09:25:45 +01:00
Alexander Shaposhnikov
34ab474348 [opt][clang] Enable using -module-summary/-flto=thin with -S/-emit-llvm
Enable using -module-summary with -S
(similarly to what currently can be achieved with opt <input> -o - | llvm-dis).
This is a recommit of ef9e62469.

Test plan: ninja check-all

Differential revision: https://reviews.llvm.org/D137768
2022-11-18 05:04:07 +00:00
Fangrui Song
77bf0df376 Revert "[opt][clang] Enable using -module-summary/-flto=thin with -S/-emit-llvm"
This reverts commit bf8381a8bc.

There is a layering violation: LLVMAnalysis depends on LLVMCore, so
LLVMCore should not include LLVMAnalysis header
llvm/Analysis/ModuleSummaryAnalysis.h
2022-11-14 15:51:03 -08:00
Alexander Shaposhnikov
bf8381a8bc [opt][clang] Enable using -module-summary/-flto=thin with -S/-emit-llvm
Enable using -module-summary with -S
(similarly to what currently can be achieved with opt <input> -o - | llvm-dis).
This is a recommit of ef9e62469.

Test plan: ninja check-all

Differential revision: https://reviews.llvm.org/D137768
2022-11-14 23:24:08 +00:00
Alexander Shaposhnikov
8c15c17e3b Revert "[opt][clang] Enable using -module-summary/-flto=thin with -S/-emit-llvm"
This reverts commit ef9e624694
for further investigation offline.
It appears to break the buildbot
llvm-clang-x86_64-sie-ubuntu-fast.
2022-11-14 21:31:30 +00:00
Alexander Shaposhnikov
ef9e624694 [opt][clang] Enable using -module-summary/-flto=thin with -S/-emit-llvm
Enable using -module-summary with -S
(similarly to what currently can be achieved with opt <input> -o - | llvm-dis).

Test plan: ninja check-all

Differential revision: https://reviews.llvm.org/D137768
2022-11-14 21:11:07 +00:00
Nikita Popov
304f1d59ca [IR] Switch everything to use memory attribute
This switches everything to use the memory attribute proposed in
https://discourse.llvm.org/t/rfc-unify-memory-effect-attributes/65579.
The old argmemonly, inaccessiblememonly and inaccessiblemem_or_argmemonly
attributes are dropped. The readnone, readonly and writeonly attributes
are restricted to parameters only.

The old attributes are auto-upgraded both in bitcode and IR.
The bitcode upgrade is a policy requirement that has to be retained
indefinitely. The IR upgrade is mainly there so it's not necessary
to update all tests using memory attributes in this patch, which
is already large enough. We could drop that part after migrating
tests, or retain it longer term, to make it easier to import IR
from older LLVM versions.

High-level Function/CallBase APIs like doesNotAccessMemory() or
setDoesNotAccessMemory() are mapped transparently to the memory
attribute. Code that directly manipulates attributes (e.g. via
AttributeList) on the other hand needs to switch to working with
the memory attribute instead.

Differential Revision: https://reviews.llvm.org/D135780
2022-11-04 10:21:38 +01:00
Nikita Popov
d41ecfab92 [X86] Use default attributes for intrinsics
This adds the default attributes (nocallback, nosync, nofree,
willreturn) to some X86 intrinsics. This will be needed to avoid
optimization regressions in the future (once we remove the
readonly -> willreturn implication for intrinsics).

Due to the number of intrinsics, this patch focuses just on the
IntrNoMem intrinsics up to the AVX2 section.

Differential Revision: https://reviews.llvm.org/D136939
2022-10-31 09:11:54 +01:00
Caroline Concatto
5431bf27bd [AArch64]Remove svget/svset/svcreate from llvm
This patch removes the aarch64 instrinsic svget/svset/svcreate from llvm.
It also implements the InstCombine for vector.extract that used to be in svget.

Depends on: D131547

Differential Revision: https://reviews.llvm.org/D131548
2022-09-23 10:48:43 +01:00
Caroline Concatto
d32b8fdbdb [LLVM][AArch64] Replace aarch64.sve.ld by aarch64.sve.ldN.sret
This patch removes the intrinsic aarch64.sve.ldN from tablegen in favour of
using arch64.sve.ldN.sret.

Depends on: D133023

Differential Revision: https://reviews.llvm.org/D133025
2022-09-20 13:15:07 +01:00
Nikita Popov
d452d5e2de [Bitcode] Fix constexpr autoupgrade for arrays and structs
While vectors use insertelement, structs and arrays should use
insertvalue.
2022-09-07 12:47:21 +02:00
Nikita Popov
0c40651f69 [Bitcode] Convert constexpr-to-instr.ll to use bitcode input (NFC)
We can't use an IR input once the relevant constant expressions
are no longer supported. Use a bitcode file instead, which will
be auto-upgraded (the whole point of this code...)
2022-09-07 12:29:32 +02:00
Sami Tolvanen
cff5bef948 KCFI sanitizer
The KCFI sanitizer, enabled with `-fsanitize=kcfi`, implements a
forward-edge control flow integrity scheme for indirect calls. It
uses a !kcfi_type metadata node to attach a type identifier for each
function and injects verification code before indirect calls.

Unlike the current CFI schemes implemented in LLVM, KCFI does not
require LTO, does not alter function references to point to a jump
table, and never breaks function address equality. KCFI is intended
to be used in low-level code, such as operating system kernels,
where the existing schemes can cause undue complications because
of the aforementioned properties. However, unlike the existing
schemes, KCFI is limited to validating only function pointers and is
not compatible with executable-only memory.

KCFI does not provide runtime support, but always traps when a
type mismatch is encountered. Users of the scheme are expected
to handle the trap. With `-fsanitize=kcfi`, Clang emits a `kcfi`
operand bundle to indirect calls, and LLVM lowers this to a
known architecture-specific sequence of instructions for each
callsite to make runtime patching easier for users who require this
functionality.

A KCFI type identifier is a 32-bit constant produced by taking the
lower half of xxHash64 from a C++ mangled typename. If a program
contains indirect calls to assembly functions, they must be
manually annotated with the expected type identifiers to prevent
errors. To make this easier, Clang generates a weak SHN_ABS
`__kcfi_typeid_<function>` symbol for each address-taken function
declaration, which can be used to annotate functions in assembly
as long as at least one C translation unit linked into the program
takes the function address. For example on AArch64, we might have
the following code:

```
.c:
  int f(void);
  int (*p)(void) = f;
  p();

.s:
  .4byte __kcfi_typeid_f
  .global f
  f:
    ...
```

Note that X86 uses a different preamble format for compatibility
with Linux kernel tooling. See the comments in
`X86AsmPrinter::emitKCFITypeId` for details.

As users of KCFI may need to locate trap locations for binary
validation and error handling, LLVM can additionally emit the
locations of traps to a `.kcfi_traps` section.

Similarly to other sanitizers, KCFI checking can be disabled for a
function with a `no_sanitize("kcfi")` function attribute.

Relands 67504c9549 with a fix for
32-bit builds.

Reviewed By: nickdesaulniers, kees, joaomoreira, MaskRay

Differential Revision: https://reviews.llvm.org/D119296
2022-08-24 22:41:38 +00:00
Sami Tolvanen
a79060e275 Revert "KCFI sanitizer"
This reverts commit 67504c9549 as using
PointerEmbeddedInt to store 32 bits breaks 32-bit arm builds.
2022-08-24 19:30:13 +00:00
Sami Tolvanen
67504c9549 KCFI sanitizer
The KCFI sanitizer, enabled with `-fsanitize=kcfi`, implements a
forward-edge control flow integrity scheme for indirect calls. It
uses a !kcfi_type metadata node to attach a type identifier for each
function and injects verification code before indirect calls.

Unlike the current CFI schemes implemented in LLVM, KCFI does not
require LTO, does not alter function references to point to a jump
table, and never breaks function address equality. KCFI is intended
to be used in low-level code, such as operating system kernels,
where the existing schemes can cause undue complications because
of the aforementioned properties. However, unlike the existing
schemes, KCFI is limited to validating only function pointers and is
not compatible with executable-only memory.

KCFI does not provide runtime support, but always traps when a
type mismatch is encountered. Users of the scheme are expected
to handle the trap. With `-fsanitize=kcfi`, Clang emits a `kcfi`
operand bundle to indirect calls, and LLVM lowers this to a
known architecture-specific sequence of instructions for each
callsite to make runtime patching easier for users who require this
functionality.

A KCFI type identifier is a 32-bit constant produced by taking the
lower half of xxHash64 from a C++ mangled typename. If a program
contains indirect calls to assembly functions, they must be
manually annotated with the expected type identifiers to prevent
errors. To make this easier, Clang generates a weak SHN_ABS
`__kcfi_typeid_<function>` symbol for each address-taken function
declaration, which can be used to annotate functions in assembly
as long as at least one C translation unit linked into the program
takes the function address. For example on AArch64, we might have
the following code:

```
.c:
  int f(void);
  int (*p)(void) = f;
  p();

.s:
  .4byte __kcfi_typeid_f
  .global f
  f:
    ...
```

Note that X86 uses a different preamble format for compatibility
with Linux kernel tooling. See the comments in
`X86AsmPrinter::emitKCFITypeId` for details.

As users of KCFI may need to locate trap locations for binary
validation and error handling, LLVM can additionally emit the
locations of traps to a `.kcfi_traps` section.

Similarly to other sanitizers, KCFI checking can be disabled for a
function with a `no_sanitize("kcfi")` function attribute.

Reviewed By: nickdesaulniers, kees, joaomoreira, MaskRay

Differential Revision: https://reviews.llvm.org/D119296
2022-08-24 18:52:42 +00:00
Fangrui Song
c2a3888793 [IR] Use Min behavior for module flag "PIC Level"
Using Max for both "PIC Level" and "PIE Level" is inconsistent. PIC imposes less
restriction while PIE imposes more restriction. The result generally
picks the more restrictive behavior: Min for PIC.

This choice matches `ld -r`: a non-pic object and a pic object merge into a
result which should be treated as non-pic.

To allow linking "PIC Level" using Error/Max from old bitcode files, upgrade
Error/Max to Min.

Reviewed By: tejohnson

Differential Revision: https://reviews.llvm.org/D130531
2022-08-18 16:28:55 -07:00
Ellis Hoag
12e78ff881 [InstrProf] Add the skipprofile attribute
As discussed in [0], this diff adds the `skipprofile` attribute to
prevent the function from being profiled while allowing profiled
functions to be inlined into it. The `noprofile` attribute remains
unchanged.

The `noprofile` attribute is used for functions where it is
dangerous to add instrumentation to while the `skipprofile` attribute is
used to reduce code size or performance overhead.

[0] https://discourse.llvm.org/t/why-does-the-noprofile-attribute-restrict-inlining/64108

Reviewed By: phosek

Differential Revision: https://reviews.llvm.org/D130807
2022-08-04 08:45:27 -07:00
Fangrui Song
a6942256ca [LegacyPM] Remove NameAnonGlobalLegacyPass
Unused after LTO removal from optimization passline.
2022-07-17 14:38:29 -07:00
Nikita Popov
2a721374ae [IR] Don't use blockaddresses as callbr arguments
Following some recent discussions, this changes the representation
of callbrs in IR. The current blockaddress arguments are replaced
with `!` label constraints that refer directly to callbr indirect
destinations:

    ; Before:
    %res = callbr i8* asm "", "=r,r,i"(i8* %x, i8* blockaddress(@test8, %foo))
    to label %asm.fallthrough [label %foo]
    ; After:
    %res = callbr i8* asm "", "=r,r,!i"(i8* %x)
    to label %asm.fallthrough [label %foo]

The benefit of this is that we can easily update the successors of
a callbr, without having to worry about also updating blockaddress
references. This should allow us to remove some limitations:

* Allow unrolling/peeling/rotation of callbr, or any other
  clone-based optimizations
  (https://github.com/llvm/llvm-project/issues/41834)
* Allow duplicate successors
  (https://github.com/llvm/llvm-project/issues/45248)

This is just the IR representation change though, I will follow up
with patches to remove limtations in various transformation passes
that are no longer needed.

Differential Revision: https://reviews.llvm.org/D129288
2022-07-15 10:18:17 +02:00
Mitch Phillips
90e5a8ac47 Remove 'no_sanitize_memtag'. Add 'sanitize_memtag'.
For MTE globals, we should have clang emit the attribute for all GV's
that it creates, and then use that in the upcoming AArch64 global
tagging IR pass. We need a positive attribute for this sanitizer (rather
than implicit sanitization of all globals) because it needs to interact
with other parts of LLVM, including:

  1. Suppressing certain global optimisations (like merging),
  2. Emitting extra directives by the ASM writer, and
  3. Putting extra information in the symbol table entries.

While this does technically make the LLVM IR / bitcode format
non-backwards-compatible, nobody should have used this attribute yet,
because it's a no-op.

Reviewed By: eugenis

Differential Revision: https://reviews.llvm.org/D128950
2022-07-13 08:54:41 -07:00
Nick Desaulniers
2240d72f15 [X86] initial -mfunction-return=thunk-extern support
Adds support for:
* `-mfunction-return=<value>` command line flag, and
* `__attribute__((function_return("<value>")))` function attribute

Where the supported <value>s are:
* keep (disable)
* thunk-extern (enable)

thunk-extern enables clang to change ret instructions into jmps to an
external symbol named __x86_return_thunk, implemented as a new
MachineFunctionPass named "x86-return-thunks", keyed off the new IR
attribute fn_ret_thunk_extern.

The symbol __x86_return_thunk is expected to be provided by the runtime
the compiled code is linked against and is not defined by the compiler.
Enabling this option alone doesn't provide mitigations without
corresponding definitions of __x86_return_thunk!

This new MachineFunctionPass is very similar to "x86-lvi-ret".

The <value>s "thunk" and "thunk-inline" are currently unsupported. It's
not clear yet that they are necessary: whether the thunk pattern they
would emit is beneficial or used anywhere.

Should the <value>s "thunk" and "thunk-inline" become necessary,
x86-return-thunks could probably be merged into x86-retpoline-thunks
which has pre-existing machinery for emitting thunks (which could be
used to implement the <value> "thunk").

Has been found to build+boot with corresponding Linux
kernel patches. This helps the Linux kernel mitigate RETBLEED.
* CVE-2022-23816
* CVE-2022-28693
* CVE-2022-29901

See also:
* "RETBLEED: Arbitrary Speculative Code Execution with Return
Instructions."
* AMD SECURITY NOTICE AMD-SN-1037: AMD CPU Branch Type Confusion
* TECHNICAL GUIDANCE FOR MITIGATING BRANCH TYPE CONFUSION REVISION 1.0
  2022-07-12
* Return Stack Buffer Underflow / Return Stack Buffer Underflow /
  CVE-2022-29901, CVE-2022-28693 / INTEL-SA-00702

SystemZ may eventually want to support "thunk-extern" and "thunk"; both
options are used by the Linux kernel's CONFIG_EXPOLINE.

This functionality has been available in GCC since the 8.1 release, and
was backported to the 7.3 release.

Many thanks for folks that provided discrete review off list due to the
embargoed nature of this hardware vulnerability. Many Bothans died to
bring us this information.

Link: https://www.youtube.com/watch?v=IF6HbCKQHK8
Link: https://github.com/llvm/llvm-project/issues/54404
Link: https://gcc.gnu.org/legacy-ml/gcc-patches/2018-01/msg01197.html
Link: https://www.intel.com/content/www/us/en/developer/articles/technical/software-security-guidance/advisory-guidance/return-stack-buffer-underflow.html
Link: https://arstechnica.com/information-technology/2022/07/intel-and-amd-cpus-vulnerable-to-a-new-speculative-execution-attack/?comments=1
Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ce114c866860aa9eae3f50974efc68241186ba60
Link: https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00702.html
Link: https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00707.html

Reviewed By: aaron.ballman, craig.topper

Differential Revision: https://reviews.llvm.org/D129572
2022-07-12 09:17:54 -07:00
Nikita Popov
b51638b3fb [Bitcode] Add additional callbr tests (NFC)
Additional coverage for the auto-upgrade code in D129288.
2022-07-11 16:46:21 +02:00
Shilei Tian
1023ddaf77 [LLVM] Add the support for fmax and fmin in atomicrmw instruction
This patch adds the support for `fmax` and `fmin` operations in `atomicrmw`
instruction. For now (at least in this patch), the instruction will be expanded
to CAS loop. There are already a couple of targets supporting the feature. I'll
create another patch(es) to enable them accordingly.

Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D127041
2022-07-06 10:57:53 -04:00
Nikita Popov
89cb8cae60 [Bitcode] Use bitcode input for test (NFC)
The constant expression used in the test will become invalid in
the future. Convert the input into bitcode, so we test that auto-
upgrade happens gracefully once this is the case.
2022-07-04 16:41:40 +02:00
Nikita Popov
941c8e0ea5 [Bitcode] Support expanding constant expressions into instructions
This implements an autoupgrade from constant expressions to
instructions, which is needed for
https://discourse.llvm.org/t/rfc-remove-most-constant-expressions/63179.

The basic approach is that constant expressions (CST_CODE_CE_*
records) now initially only create a BitcodeConstant value that
holds opcode, flags and operands IDs. Then, when the value actually
gets used, it can be converted either into a constant expression
(if that expression type is still supported) or into a sequence of
instructions. As currently all expressions are still supported,
-expand-constant-exprs is added for testing purposes, to force
expansion.

PHI nodes require special handling, because the constant expression
needs to be evaluated on the incoming edge. We do this by putting
it into a temporary block and then wiring it up appropriately
afterwards (for non-critical edges, we could also move the
instructions into the predecessor).

This also removes the need for the forward referenced constants
machinery, as the BitcodeConstants only hold value IDs. At the
point where the value is actually materialized, no forward
references are needed anymore.

Differential Revision: https://reviews.llvm.org/D127729
2022-06-28 11:09:46 +02:00
Bradley Smith
a83aa33d1b [IR] Move vector.insert/vector.extract out of experimental namespace
These intrinsics are now fundemental for SVE code generation and have been
present for a year and a half, hence move them out of the experimental
namespace.

Differential Revision: https://reviews.llvm.org/D127976
2022-06-27 10:48:45 +00:00
Mitch Phillips
8db981d463 Add sanitizer-specific GlobalValue attributes.
Plan is the migrate the global variable metadata for sanitizers, that's
currently carried around generally in the 'llvm.asan.globals' section,
onto the global variable itself.

This patch adds the attribute and plumbs it through the LLVM IR and
bitcode formats, but is a no-op other than that so far.

Reviewed By: vitalybuka, kstoimenov

Differential Revision: https://reviews.llvm.org/D126100
2022-06-10 12:28:18 -07:00
Nikita Popov
471bfb7016 [Bitcode] Re-enable verify-uselistorder test (NFC)
This issue has since been fixed, so re-enable the commented RUN
line.
2022-06-08 11:29:28 +02:00
Augie Fackler
42861faa8e attributes: introduce allockind attr for describing allocator fn behavior
I chose to encode the allockind information in a string constant because
otherwise we would get a bit of an explosion of keywords to deal with
the possible permutations of allocation function types.

I'm not sure that CodeGen.h is the correct place for this enum, but it
seemed to kind of match the UWTableKind enum so I put it in the same
place. Constructive suggestions on a better location most certainly
encouraged.

Differential Revision: https://reviews.llvm.org/D123088
2022-05-31 10:01:17 -04:00
Takafumi Arakaki
18e6b8234a Allow pointer types for atomicrmw xchg
This adds support for pointer types for `atomic xchg` and let us write
instructions such as `atomicrmw xchg i64** %0, i64* %1 seq_cst`. This
is similar to the patch for allowing atomicrmw xchg on floating point
types: https://reviews.llvm.org/D52416.

Differential Revision: https://reviews.llvm.org/D124728
2022-05-25 16:20:26 +00:00
Ahmed Bougacha
362b4066f0 [ObjCARC] Drop nullary clang.arc.attachedcall bundles in autoupgrade.
In certain use-cases, these can be emitted by old compilers, but the
operand is now always required.  These are only used for optimizations,
so it's safe to drop them if they happen to have the now-invalid format.
The semantically-required call is already a separate instruction.

Differential Revision: https://reviews.llvm.org/D123811
2022-05-20 15:27:29 -07:00
Wende Tan
6baaad740a [Bitcode] Include indirect users of BlockAddresses in bitcode
The original fix (commit 23ec5782c3) of
https://github.com/llvm/llvm-project/issues/52787 only adds `Function`s
that have `Instruction`s that directly use `BlockAddress`es into the
bitcode (`FUNC_CODE_BLOCKADDR_USERS`).

However, in either @rickyz's original reproducing code:

```
void f(long);

__attribute__((noinline)) static void fun(long x) {
  f(x + 1);
}

void repro(void) {
  fun(({
    label:
      (long)&&label;
  }));
}
```

```
...
define dso_local void @repro() #0 {
entry:
  br label %label

label:                                            ; preds = %entry
  tail call fastcc void @fun()
  ret void
}

define internal fastcc void @fun() unnamed_addr #1 {
entry:
  tail call void @f(i64 add (i64 ptrtoint (i8* blockaddress(@repro, %label) to i64), i64 1)) #3
  ret void
}
...
```

or the xfs and overlayfs in the Linux kernel, `BlockAddress`es (e.g.,
`i8* blockaddress(@repro, %label)`) may first compose `ConstantExpr`s
(e.g., `i64 ptrtoint (i8* blockaddress(@repro, %label) to i64)`) and
then used by `Instruction`s. This case is not handled by the original
fix.

This patch adds *indirect* users of `BlockAddress`es, i.e., the
`Instruction`s using some `Constant`s which further use the
`BlockAddress`es, into the bitcode as well, by doing depth-first
searches.

Fixes: https://github.com/llvm/llvm-project/issues/52787
Fixes: 23ec5782c3 ("[Bitcode] materialize Functions early when BlockAddress taken")

Reviewed By: nickdesaulniers

Differential Revision: https://reviews.llvm.org/D124878
2022-05-10 16:03:42 -07:00
Augie Fackler
a907d36cfe Attributes: add a new allocptr attribute
This continues the push away from hard-coded knowledge about functions
towards attributes. We'll use this to annotate free(), realloc() and
cousins and obviate the hard-coded list of free functions.

Differential Revision: https://reviews.llvm.org/D123083
2022-04-26 13:57:11 -04:00
Alex Richardson
9107cd632d [AutoUpgrade] Don't lose attributes when upgrading mem intrinsics
The original AutoUpgrade code from 1e68724d24
did not retain existing attributes. I noticed this in some downstream test
cases, but it turns out there are also two affected testcase upstream.

Differential Revision: https://reviews.llvm.org/D121971
2022-04-13 09:30:10 +00:00
Daniel Kiss
b0343a38a5 Support the min of module flags when linking, use for AArch64 BTI/PAC-RET
LTO objects might compiled with different `mbranch-protection` flags which will cause an error in the linker.
Such a setup is allowed in the normal build with this change that is possible.

Reviewed By: pcc

Differential Revision: https://reviews.llvm.org/D123493
2022-04-13 09:31:51 +02:00
Nick Desaulniers
23ec5782c3 [Bitcode] materialize Functions early when BlockAddress taken
IRLinker builds a work list of functions to materialize, then moves them
from a source module to a destination module one at a time.

This is a problem for blockaddress Constants, since they need not refer
to the function they are used in; IPSCCP is quite good at sinking these
constants deep into other functions when passed as arguments.

This would lead to curious errors during LTO:
  ld.lld: error: Never resolved function from blockaddress ...
based on the ordering of function definitions in IR.

The problem was that IRLinker would basically do:

  for function f in worklist:
    materialize f
    splice f from source module to destination module

in one pass, with Functions being lazily added to the running worklist.
This confuses BitcodeReader, which cannot disambiguate whether a
blockaddress is referring to a function which has not yet been parsed
("materialized") or is simply empty because its body was spliced out.
This causes BitcodeReader to insert Functions into its BasicBlockFwdRefs
list incorrectly, as it will never re-materialize an already
materialized (but spliced out) function.

Because of the possibility that blockaddress Constants may appear in
Functions other than the ones they reference, this patch adds a new
bitcode function code FUNC_CODE_BLOCKADDR_USERS that is a simple list of
Functions that contain BlockAddress Constants that refer back to this
Function, rather then the Function they are scoped in. We then
materialize those functions when materializing `f` from the example loop
above. This might over-materialize Functions should the user of
BitcodeReader ultimately decide not to link those Functions, but we can
at least now we can avoid this ordering related issue with blockaddresses.

Fixes: https://github.com/llvm/llvm-project/issues/52787
Fixes: https://github.com/ClangBuiltLinux/linux/issues/1215

Reviewed By: dexonsmith

Differential Revision: https://reviews.llvm.org/D120781
2022-04-12 11:38:35 -07:00