131 Commits

Author SHA1 Message Date
AdityaK
391bf068f2
[LTO] Print conflicting operands between Src and Dest modules (#115104)
The current error message doesn't give sufficient details to help with
debugging. This patch will log the operand values that are conflicting.

After this patch the output is of the form:
```
'Large Data Threshold': IDs have conflicting values: 'i32 101' from /usr/local/home/llvm-project/build/test/LTO/X86/Output/largedatathreshold-3.ll.tmp1.o, and 'i32 100' from ld-temp.o
```
2024-11-21 10:07:39 -08:00
Mingming Liu
af784a5c13
[ThinLTO] Use a set rather than a map to track exported ValueInfos. (#97360)
https://github.com/llvm/llvm-project/pull/95482 is a reland of
https://github.com/llvm/llvm-project/pull/88024.
https://github.com/llvm/llvm-project/pull/95482 keeps indexing memory
usage reasonable by using unordered_map and doesn't make other changes
to originally reviewed code.

While discussing possible ways to minimize indexing memory usage, Teresa
asked whether I need `ExportSetTy` as a map or a set is sufficient. This
PR implements the idea. It uses a set rather than a map to track exposed
ValueInfos.

Currently, `ExportLists` has two use cases, and neither needs to track a
ValueInfo's import/export status. So using a set is sufficient and
correct.
1) In both in-process and distributed ThinLTO, it's used to decide if a
function or global variable is visible [1] from another module after importing
creates additional cross-module references.
     * If a cross-module call edge is seen today, the callee must be visible
       to another module without keeping track of its export status already.
       For instance, this [2] is how callees of direct calls get exported.
2) For in-process ThinLTO [3], it's used to compute lto cache key.
     * The cache key computation already hashes [4] 'ImportList' , and 'ExportList' is
        determined by 'ImportList'. So it's fine to not track 'import type' for export list.

[1] 66cd8ec4c0/llvm/lib/LTO/LTO.cpp (L1815-L1819)
[2] 66cd8ec4c0/llvm/lib/LTO/LTO.cpp (L1783-L1794)
[3] 66cd8ec4c0/llvm/lib/LTO/LTO.cpp (L1494-L1496)
[4] b76100e220/llvm/lib/LTO/LTO.cpp (L194-L222)
2024-07-03 13:15:17 -07:00
Mingming Liu
8d9db947b7
Reland "[ThinLTO] Populate declaration import status except for distributed ThinLTO under a default-off new option" (#95482)
Make `FunctionsToImportTy` an `unordered_map` rather than `DenseMap`.
Credit goes to jvoung@ for the 'DenseMap -> unordered_map' change. This
is a reland of https://github.com/llvm/llvm-project/pull/92718

* `DenseMap` allocates space for a large number of key/value pairs and
wastes space when the number of elements are small.
* While init bucket size is zero [1], it quickly allocates buckets for 64 elements [2]
when the number of elements is small (for example, 3 or 4 elements). The programmer
manual [3] also mentions it could waste space.
* Experiments show `FunctionsToImportTy.size()` is smaller than 4 for
multiple binaries with high indexing ram usage. `unordered_map` grows
factor is at most 2 in llvm libc [4] for insert operations.
 
With this change, `ComputeCrossModuleImport` ram increase is smaller
than 0.5G on a couple of binaries with high indexing ram usage. A wider
range of (pre-release) tests pass.

[1] ad79a14c9e/llvm/include/llvm/ADT/DenseMap.h (L431-L432) 
[2] ad79a14c9e/llvm/include/llvm/ADT/DenseMap.h (L849)
[3] https://llvm.org/docs/ProgrammersManual.html#llvm-adt-densemap-h
[4] ad79a14c9e/libcxx/include/__hash_table (L1525-L1526)

**Original commit message** 
The goal is to populate `declaration` import status if a new flag
`-import-declaration` is on.

* For in-process ThinLTO, the `declaration` status is visible to backend
`function-import` pass, so `FunctionImporter::importFunctions` should
read the import status and be no-op for declaration summaries.
Basically, the postlink pipeline is updated to keep its current behavior
(import definitions), but not updated to handle `declaration` summaries.
Two use cases ([better call-graph
sort](https://discourse.llvm.org/t/rfc-for-better-call-graph-sort-build-a-more-complete-call-graph-by-adding-more-indirect-call-edges/74029#support-cross-module-function-declaration-import-5)
or [cross-module
auto-init](https://github.com/llvm/llvm-project/pull/87597#discussion_r1556067195))
would use this bit differently.

* For distributed ThinLTO, the `declaration` status is not serialized to
bitcode. As discussed, https://github.com/llvm/llvm-project/pull/87600
will do this.
2024-06-20 10:50:31 -07:00
Mingming Liu
707f4de428
Revert "Reland "[ThinLTO] Populate declaration import status except for distributed ThinLTO under a default-off new option" (#92718) (#94503)
This reverts commit e33db249b53fb70dce62db3ebd82d42239bd1d9d.

The change from *set to *map increases memory usage, and caused indexing
OOM in some applications. Need to profile offline to bring the memory
usage down.
2024-06-05 10:06:55 -07:00
Mingming Liu
e33db249b5
Reland "[ThinLTO] Populate declaration import status except for distributed ThinLTO under a default-off new option" (#92718)
The original PR is reviewed in
https://github.com/llvm/llvm-project/pull/88024, and this PR adds one
line (b9f04d199d)
to fix test

Limit to one thread for in-process ThinLTO to test `LLVM_DEBUG` log.
- This should fix build bot failure like
https://lab.llvm.org/buildbot/#/builders/259/builds/4727 and
https://lab.llvm.org/buildbot/#/builders/9/builds/43876
- I could repro the failure and see interleaved log messages by using
`-thinlto-threads=all`

**Original Commit Message:**

The goal is to populate `declaration` import status if a new flag
`-import-declaration` is on.

* For in-process ThinLTO, the `declaration` status is visible to backend
`function-import` pass, so `FunctionImporter::importFunctions` should
read the import status and be no-op for declaration summaries.
Basically, the postlink pipeline is updated to keep its current behavior
(import definitions), but not updated to handle `declaration` summaries.
Two use cases ([better call-graph
sort](https://discourse.llvm.org/t/rfc-for-better-call-graph-sort-build-a-more-complete-call-graph-by-adding-more-indirect-call-edges/74029#support-cross-module-function-declaration-import-5)
or [cross-module
auto-init](https://github.com/llvm/llvm-project/pull/87597#discussion_r1556067195))
would use this bit differently.

* For distributed ThinLTO, the `declaration` status is not serialized to
bitcode. As discussed, https://github.com/llvm/llvm-project/pull/87600
will do this.
2024-05-20 08:55:31 -07:00
Mingming Liu
6b0733e3a3
Revert "[ThinLTO] Populate declaration import status except for distributed ThinLTO under a default-off new option" (#92715)
Reverts llvm/llvm-project#88024

Build bot failures
(https://lab.llvm.org/buildbot/#/builders/259/builds/4727 and
https://lab.llvm.org/buildbot/#/builders/9/builds/43876)
2024-05-19 22:42:18 -07:00
Mingming Liu
8de7890572
[ThinLTO] Populate declaration import status except for distributed ThinLTO under a default-off new option (#88024)
The goal is to populate `declaration` import status if a new flag`-import-declaration` is on.

* For in-process ThinLTO, the `declaration` status is visible to backend
`function-import` pass, so `FunctionImporter::importFunctions` should
read the import status and be no-op for declaration summaries.
Basically, the postlink pipeline is updated to keep its current behavior
(import definitions), but not updated to handle `declaration` summaries.
Two use cases (better call-graph sort and cross-module auto-init)
would use this bit differently.

* For distributed ThinLTO, the `declaration` status is not serialized to
bitcode. As discussed, https://github.com/llvm/llvm-project/pull/87600
will do this.

[1] https://discourse.llvm.org/t/rfc-for-better-call-graph-sort-build-a-more-complete-call-graph-by-adding-more-indirect-call-edges/74029#support-cross-module-function-declaration-import-5
[2] https://github.com/llvm/llvm-project/pull/87597#discussion_r1556067195
2024-05-19 22:22:47 -07:00
lifengxiang1025
daf3079222
[ThinLTO] Add metedata 'thinlto_src_module' and 'thinlto_src_file' (#83110)
Originally, when `EnableImportMetadata` enabled, `SourceFileName` will
be recorded as `thinlto_src_module`. Now `SourceFileName` will be
recorded as `thinlto_src_file` and `ModuleIdentifier` will be recorded
as `thinlto_src_module`.
2024-02-29 10:42:06 +08:00
Teresa Johnson
4638eb2660 [ThinLTO] Ignore callee edge to global variable
Since the symbols in the ThinLTO summary are indexed by GUID we can end
up in corner cases where a callee edge in the combined index goes to a
summary for a global variable. This could happen in the case of hash
collisions, and in the case of SamplePGO profiles could potentially happen
due to code changes (since we synthesize call edges to GUIDs that were
inlined callees in the profiled code).

Handle this by simply ignoring any non-FunctionSummary callees.

Differential Revision: https://reviews.llvm.org/D152406
2023-06-08 06:44:06 -07:00
Fangrui Song
f53de29862 [FunctionImport] Change IRMover report_fatal_error to a proper error
Conflicting module flags leads to a proper error for regular LTO but a crash
(report_fatal_error) for ThinLTO. Switch to createStringError to fix the crash
and match regular LTO.
2023-02-23 21:45:14 -08:00
Arthur Eubanks
86ced82099 Revert "[IRMover] Remove UB implying parameter attributes when necessary"
This reverts commit 451799bb8261bde52bbfef226d019caf1d82aa42.

Causes crashes, see D139209
2023-02-22 09:40:39 -08:00
Tim Neumann
451799bb82 [IRMover] Remove UB implying parameter attributes when necessary
When importing functions from some module X into some module Y, they may reference other functions already present in Y. The signature (especially attributes) of those other functions may have diverged between X and Y (e.g. due to the Dead Argument Elimination optimization). If necessary, modify the attributes to avoid UB.

See the added test and implementation comments for more details.

This was exposed by https://reviews.llvm.org/D133036 before it was reverted. Fixes https://github.com/llvm/llvm-project/issues/58976.

Reviewed By: tejohnson

Differential Revision: https://reviews.llvm.org/D139209
2023-02-21 18:35:31 +01:00
Nikita Popov
3713bc8a0b [FunctionImport] Convert tests to opaque pointers (NFC) 2022-12-13 16:14:34 +01:00
Fangrui Song
a9af1b9a30 [test] Change -function-import tests to use -passes= 2022-07-17 21:43:00 -07:00
Fangrui Song
59fafdd815 [test] Migrate FunctionImport/cg_profile.ll to new PM 2022-07-16 01:10:39 -07:00
Wolfgang Pieb
ff87ee4dee [Metadata] Utilize the resizing capability of MDNodes in Moduleflag processing.
This mostly affects PGO/LTO builds which use module flags describing the call
graph. Fixes Issue #51893.

Reviewed By: dexonsmith

Differential Revision: https://reviews.llvm.org/D125999
2022-07-06 10:18:33 -07:00
Nikita Popov
41d5033eb1 [IR] Enable opaque pointers by default
This enabled opaque pointers by default in LLVM. The effect of this
is twofold:

* If IR that contains *neither* explicit ptr nor %T* types is passed
  to tools, we will now use opaque pointer mode, unless
  -opaque-pointers=0 has been explicitly passed.
* Users of LLVM as a library will now default to opaque pointers.
  It is possible to opt-out by calling setOpaquePointers(false) on
  LLVMContext.

A cmake option to toggle this default will not be provided. Frontends
or other tools that want to (temporarily) keep using typed pointers
should disable opaque pointers via LLVMContext.

Differential Revision: https://reviews.llvm.org/D126689
2022-06-02 09:40:56 +02:00
Nikita Popov
f430c1eb64 [Tests] Add elementtype attribute to indirect inline asm operands (NFC)
This updates LLVM tests for D116531 by adding elementtype attributes
to operands that correspond to indirect asm constraints.
2022-01-06 14:23:51 +01:00
Zarko Todorovski
7f7dac7126 [NFC][llvm] Inclusive language: reword uses of sanity test and check
Part of continuing work to use more inclusive language. Reworded uses
of sanity check and sanity test in llvm/test/
2021-11-25 07:21:42 -05:00
serge-sans-paille
4ab3041acb Revert "[NFC] remove explicit default value for strboolattr attribute in tests"
This reverts commit bda6e5bee04c75b1f1332b4fd1ac4e8ef6c3c247.

See https://lab.llvm.org/buildbot/#/builders/109/builds/15424 for instance
2021-05-24 19:43:40 +02:00
serge-sans-paille
bda6e5bee0 [NFC] remove explicit default value for strboolattr attribute in tests
Since d6de1e1a71406c75a4ea4d5a2fe84289f07ea3a1, no attributes is quivalent to
setting attribute to false.

This is a preliminary commit for https://reviews.llvm.org/D99080
2021-05-24 19:31:04 +02:00
Yaxun (Sam) Liu
bf6124580d [HIP] support ThinLTO
Add options -[no-]offload-lto and -foffload-lto=[thin,full] for controlling
LTO for offload compilation. Allow LTO for AMDGPU target.

AMDGPU target does not support codegen of object files containing
call of external functions, therefore the LLVM module passed to
AMDGPU backend needs to contain definitions of all the callees.
An LLVM option is added to allow function importer to import
functions with noinline attribute.

HIP toolchain passes proper LLVM options to lld to make sure
function importer imports definitions of all the callees.

Reviewed by: Teresa Johnson, Artem Belevich

Differential Revision: https://reviews.llvm.org/D99683
2021-05-22 10:48:34 -04:00
Yuanfang Chen
a223354161 [CGProfile] allows bitcast in metadata node storing function pointers
For example,  during RAUW in IRMover, the `Function` ValueAsMetadata in "CG Profile" could become bitcast.

Reviewed By: tejohnson

Differential Revision: https://reviews.llvm.org/D88433
2020-11-13 09:28:21 -08:00
Simon Pilgrim
2dcef0196b [FunctionImport] Remove unused check-prefixes 2020-11-09 17:21:29 +00:00
Yuanfang Chen
4ad7685258 Revert "Revert "Reland "[Support] make report_fatal_error abort instead of exit"""
This reverts commit 80a34ae31125aa46dcad47162ba45b152aed968d with fixes.

Previously, since bots turning on EXPENSIVE_CHECKS are essentially turning on
MachineVerifierPass by default on X86 and the fact that
inline-asm-avx-v-constraint-32bit.ll and inline-asm-avx512vl-v-constraint-32bit.ll
are not expected to generate functioning machine code, this would go
down to `report_fatal_error` in MachineVerifierPass. Here passing
`-verify-machineinstrs=0` to make the intent explicit.
2020-02-13 10:16:06 -08:00
Yuanfang Chen
17122ec10a Revert "Revert "Revert "Reland "[Support] make report_fatal_error abort instead of exit""""
This reverts commit bb51d243308dbcc9a8c73180ae7b9e47b98e68fb.
2020-02-13 10:08:05 -08:00
Yuanfang Chen
bb51d24330 Revert "Revert "Reland "[Support] make report_fatal_error abort instead of exit"""
This reverts commit 80a34ae31125aa46dcad47162ba45b152aed968d with fixes.

On bots llvm-clang-x86_64-expensive-checks-ubuntu and
llvm-clang-x86_64-expensive-checks-debian only,
llc returns 0 for these two tests unexpectedly. I tweaked the RUN line a little
bit in the hope that LIT is the culprit since this change is not in the
codepath these tests are testing.
llvm\test\CodeGen\X86\inline-asm-avx-v-constraint-32bit.ll
llvm\test\CodeGen\X86\inline-asm-avx512vl-v-constraint-32bit.ll
2020-02-13 10:02:53 -08:00
Yuanfang Chen
80a34ae311 Revert "Reland "[Support] make report_fatal_error abort instead of exit""
This reverts commit rGcd5b308b828e, rGcd5b308b828e, rG8cedf0e2994c.

There are issues to be investigated for polly bots and bots turning on
EXPENSIVE_CHECKS.
2020-02-11 20:41:53 -08:00
Yuanfang Chen
8cedf0e299 Reland "[Support] make report_fatal_error abort instead of exit"
Summary:
Reland D67847 after D73742 is committed. Replace `sys::Process::Exit(1)`
with `abort` in `report_fatal_error`.

After this patch, for tools turning on `CrashRecoveryContext`,
crash handler installed by `CrashRecoveryContext` is called unless
they installed a non-returning handler using `llvm::install_fatal_error_handler`
like `cc1_main` currently does.

Reviewers: rnk, MaskRay, aganea, hans, espindola, jhenderson

Subscribers: jholewinski, qcolombet, dschuff, jyknight, emaste, sdardis, nemanjai, jvesely, nhaehnle, sbc100, jgravelle-google, hiraditya, aheejin, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, sabuasal, niosHD, jrtc27, zzheng, edward-jones, atanasyan, steven_wu, rogfer01, MartinMosbeck, brucehoult, the_o, dexonsmith, PkmX, rupprecht, jocewei, jsji, Jim, dmgreen, lenary, s.egerton, pzheng, sameer.abuasal, apazos, luismarques, kerbowa, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D74456
2020-02-11 18:20:40 -08:00
Yuanfang Chen
6e24c6037f Revert "[Support] make report_fatal_error abort instead of exit"
This reverts commit 647c3f4e47de8a850ffcaa897db68702d8d2459a.

Got bots failure from sanitizer-windows and maybe others.
2020-01-15 17:52:25 -08:00
Yuanfang Chen
647c3f4e47 [Support] make report_fatal_error abort instead of exit
Summary:
This patch could be treated as a rebase of D33960. It also fixes PR35547.
A fix for `llvm/test/Other/close-stderr.ll` is proposed in D68164. Seems
the consensus is that the test is passing by chance and I'm not
sure how important it is for us. So it is removed like in D33960 for now.
The rest of the test fixes are just adding `--crash` flag to `not` tool.

** The reason it fixes PR35547 is

`exit` does cleanup including calling class destructor whereas `abort`
does not do any cleanup. In multithreading environment such as ThinLTO or JIT,
threads may share states which mostly are ManagedStatic<>. If faulting thread
tearing down a class when another thread is using it, there are chances of
memory corruption. This is bad 1. It will stop error reporting like pretty
stack printer; 2. The memory corruption is distracting and nondeterministic in
terms of error message, and corruption type (depending one the timing, it
could be double free, heap free after use, etc.).

Reviewers: rnk, chandlerc, zturner, sepavloff, MaskRay, espindola

Reviewed By: rnk, MaskRay

Subscribers: wuzish, jholewinski, qcolombet, dschuff, jyknight, emaste, sdardis, nemanjai, jvesely, nhaehnle, sbc100, arichardson, jgravelle-google, aheejin, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, jsji, lenary, s.egerton, pzheng, cfe-commits, MaskRay, filcab, davide, MatzeB, mehdi_amini, hiraditya, steven_wu, dexonsmith, rupprecht, seiya, llvm-commits

Tags: #llvm, #clang

Differential Revision: https://reviews.llvm.org/D67847
2020-01-15 17:05:13 -08:00
Fangrui Song
502a77f125 Migrate function attribute "no-frame-pointer-elim" to "frame-pointer"="all" as cleanups after D56351 2019-12-24 15:57:33 -08:00
Amy Huang
7b1d793713 Reland "Change the X86 datalayout to add three address spaces
for 32 bit signed, 32 bit unsigned, and 64 bit pointers."
This reverts 57076d3199fc2b0af4a3736b7749dd5462cacda5.

Original review at https://reviews.llvm.org/D64931.
Review for added fix at https://reviews.llvm.org/D66843.

llvm-svn: 371568
2019-09-10 23:15:38 +00:00
Vlad Tsyrklevich
57076d3199 Revert "Change the X86 datalayout to add three address spaces for 32 bit signed,"
This reverts commit r370083 because it caused check-lld failures on
sanitizer-x86_64-linux-fast.

llvm-svn: 370142
2019-08-28 01:08:54 +00:00
Amy Huang
1299945b81 Change the X86 datalayout to add three address spaces for 32 bit signed,
32 bit unsigned, and 64 bit pointers.

llvm-svn: 370083
2019-08-27 17:46:53 +00:00
Eric Christopher
cee313d288 Revert "Temporarily Revert "Add basic loop fusion pass.""
The reversion apparently deleted the test/Transforms directory.

Will be re-reverting again.

llvm-svn: 358552
2019-04-17 04:52:47 +00:00
Eric Christopher
a863435128 Temporarily Revert "Add basic loop fusion pass."
As it's causing some bot failures (and per request from kbarton).

This reverts commit r358543/ab70da07286e618016e78247e4a24fcb84077fda.

llvm-svn: 358546
2019-04-17 02:12:23 +00:00
Teresa Johnson
f59242e5ff Recommit "[ThinLTO] Rename COMDATs for COFF when promoting/renaming COMDAT leader"
Recommit of r352763 with fix for use after free.

llvm-svn: 352770
2019-01-31 17:18:11 +00:00
Teresa Johnson
4877715ee6 Revert "[ThinLTO] Rename COMDATs for COFF when promoting/renaming COMDAT leader"
This reverts commit r352763.

Causing a couple bot failures, root cause pointed to by sanitizer bot:
http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-fast/builds/28909/steps/annotate/logs/stdio

Use after free. I understand the issue but will revert and test with fix
before recommitting.

llvm-svn: 352768
2019-01-31 16:46:14 +00:00
Teresa Johnson
992b53fd16 [ThinLTO] Rename COMDATs for COFF when promoting/renaming COMDAT leader
Summary:
COFF requires that COMDAT name match that of the leader. When we promote
and rename an internal leader in ThinLTO due to an import, ensure we
subsequently rename the associated COMDAT. Similar to D31963 which did
this during ThinLTO module splitting.

Fixes PR40414.

Reviewers: pcc, inglorion

Subscribers: mehdi_amini, dexonsmith, dmajor, llvm-commits

Differential Revision: https://reviews.llvm.org/D57395

llvm-svn: 352763
2019-01-31 16:00:15 +00:00
Teresa Johnson
5b8ff375c8 [ThinLTO] Allow importing of functions with var args
Summary:
Follow up to D54270, which allowed importing of var args functions
unless they called va_start. As pointed out in the post-commit comments
on that patch, the inliner can handle functions that call va_start in
certain situations as well. Go ahead and enable importing of all var
args functions. Measurements on a large binary show that this increases
imports and binary size by an insignificant amount.

Reviewers: davidxl

Subscribers: mehdi_amini, inglorion, eraman, steven_wu, dexonsmith, llvm-commits

Differential Revision: https://reviews.llvm.org/D54607

llvm-svn: 348068
2018-12-01 05:11:46 +00:00
Teresa Johnson
32dc5b9bf1 [ThinLTO] Update handling of vararg functions to match inliner
Summary:
Previously we marked all vararg functions as non-inlinable in the
function summary, which prevented their importing. However, the
corresponding inliner restriction was loosened in r321940/r342675
to only apply to functions calling va_start. Adjust the summary
flag computation to match.

Reviewers: davidxl

Subscribers: mehdi_amini, inglorion, eraman, steven_wu, dexonsmith, llvm-commits

Differential Revision: https://reviews.llvm.org/D54270

llvm-svn: 346883
2018-11-14 19:30:13 +00:00
Pirama Arumuga Nainar
e61652a384 [LTO] Drop non-prevailing definitions only if linkage is not local or appending
Summary:
This fixes PR 37422

In ELF, non-weak symbols can also be non-prevailing.  In this particular
PR, the __llvm_profile_* symbols are non-prevailing but weren't getting
dropped - causing multiply-defined errors with lld.

Also add a test, strong_non_prevailing.ll, to ensure that multiple
copies of a strong symbol are dropped.

To fix the test regressions exposed by this fix,
- do not mark prevailing copies for symbols with 'appending' linkage.
There's no one prevailing copy for such symbols.
- fix the prevailing version in dead-strip-fulllto.ll
- explicitly pass exported symbols to llvm-lto in fumcimport.ll and
funcimport_var.ll

Reviewers: tejohnson, pcc

Subscribers: mehdi_amini, inglorion, eraman, steven_wu, dexonsmith,
dang, srhines, llvm-commits

Differential Revision: https://reviews.llvm.org/D54125

llvm-svn: 346436
2018-11-08 20:10:07 +00:00
Teresa Johnson
f2d4b1d902 New test requires x86-registered-target
New test added in r344658 also requires x86-registered-target.

llvm-svn: 344662
2018-10-17 00:59:14 +00:00
Teresa Johnson
cd00f564f8 [ThinLTO] Fix test to require asserts
New test added in r344658 requires asserts due to -stats.

While here, augment it to test new global variable importing
message as well.

llvm-svn: 344660
2018-10-17 00:19:21 +00:00
Teresa Johnson
d2c234a4cc [ThinLTO] Add importing stats to thin link
Summary:
Previously we could only get the number of imported functions and
variables from the backend. This adds stats to the thin link where the
importing is decided.

Reviewers: wmi

Subscribers: inglorion, dexonsmith, llvm-commits

Differential Revision: https://reviews.llvm.org/D53337

llvm-svn: 344658
2018-10-16 23:49:50 +00:00
Xin Tong
bfdad33b82 [ThinLTO] Keep non-prevailing (linkonce|weak)_odr symbols live
Summary:
If we have a symbol with (linkonce|weak)_odr linkage, we do not want
to dead strip it even it is not prevailing.

IR level (linkonce|weak)_odr symbol can become non-prevailing when we mix
ELF objects and IR objects where the (linkonce|weak)_odr symbol in the ELF
object is prevailing and the ones in the IR objects are not. Stripping
them will prevent us from doing optimizations with them.

By not dead stripping them, We will convert these symbols to
available_externally linkage as a result of non-prevailing and eventually
dropping them after inlining.

I modified cache-prevailing.ll to use linkonce linkage as it is
testing whether cache prevailing bit is effective or not, not
we should treat linkonce_odr alive or not

Reviewers: tejohnson, pcc

Subscribers: mehdi_amini, inglorion, eraman, steven_wu, dexonsmith, llvm-commits

Differential Revision: https://reviews.llvm.org/D52893

llvm-svn: 343970
2018-10-08 15:12:48 +00:00
Teresa Johnson
d68935c5ac Restore "[ThinLTO] Ensure we always select the same function copy to import"
This reverts commit r337081, therefore restoring r337050 (and fix in
r337059), with test fix for bot failure described after the original
description below.

In order to always import the same copy of a linkonce function,
even when encountering it with different thresholds (a higher one then a
lower one), keep track of the summary we decided to import.
This ensures that the backend only gets a single definition to import
for each GUID, so that it doesn't need to choose one.

Move the largest threshold the GUID was considered for import into the
current module out of the ImportMap (which is part of a larger map
maintained across the whole index), and into a new map just maintained
for the current module we are computing imports for. This saves some
memory since we no longer have the thresholds maintained across the
whole index (and throughout the in-process backends when doing a normal
non-distributed ThinLTO build), at the cost of some additional
information being maintained for each invocation of ComputeImportForModule
(the selected summary pointer for each import).

There is an additional map lookup for each callee being considered for
importing, however, this was able to subsume a map lookup in the
Worklist iteration that invokes computeImportForFunction. We also are
able to avoid calling selectCallee if we already failed to import at the
same or higher threshold.

I compared the run time and peak memory for the SPEC2006 471.omnetpp
benchmark (running in-process ThinLTO backends), as well as for a large
internal benchmark with a distributed ThinLTO build (so just looking at
the thin link time/memory). Across a number of runs with and without
this change there was no significant change in the time and memory.

(I tried a few other variations of the change but they also didn't
improve time or peak memory).

The new commit removes a test that no longer makes sense
(Transforms/FunctionImport/hotness_based_import2.ll), as exposed by the
reverse-iteration bot. The test depends on the order of processing the
summary call edges, and actually depended on the old problematic
behavior of selecting more than one summary for a given GUID when
encountered with different thresholds. There was no guarantee even
before that we would eventually pick the linkonce copy with the hottest
call edges, it just happened to work with the test and the old code, and
there was no guarantee that we would end up importing the selected
version of the copy that had the hottest call edges (since the backend
would effectively import only one of the selected copies).

Reviewers: davidxl

Subscribers: mehdi_amini, inglorion, llvm-commits

Differential Revision: https://reviews.llvm.org/D48670

llvm-svn: 337184
2018-07-16 15:30:27 +00:00
Teresa Johnson
b78c5d0602 Revert "[ThinLTO] Ensure we always select the same function copy to import"
This reverts commits r337050 and r337059. Caused failure in
reverse-iteration bot that needs more investigation.

llvm-svn: 337081
2018-07-14 01:45:49 +00:00
Teresa Johnson
8e739f98fe Revert "[ThinLTO] Add debug output to test"
This reverts commit r337076. Not needed any more.

llvm-svn: 337080
2018-07-14 01:34:06 +00:00