Commit Graph

19 Commits

Author SHA1 Message Date
Teresa Johnson 9f2ff9c669 [ThinLTO] Debug message cleanup (NFC)
Added some missing spaces between the module identifier and the start of
the debug message. Also added a ":" after the module identifier to make
this look a little nicer.

llvm-svn: 255259
2015-12-10 16:39:07 +00:00
Rafael Espindola 9edc3b8403 Don't assign a temporary string to a StringRef.
Should fix the windows debug and asan bots.

llvm-svn: 255149
2015-12-09 20:41:10 +00:00
Teresa Johnson 7f961e14d3 [ThinLTO] FunctionImport pass can take a const index pointer (NFC)
llvm-svn: 255140
2015-12-09 19:39:47 +00:00
Mehdi Amini 7e88d0da38 The current importing scheme is processing one function at a time,
loading the source Module, linking the function in the destination
module, and destroying the source Module before repeating with the
next function to import (potentially from the same Module).

Ideally we would keep the source Module alive and import the next
Function needed from this Module. Unfortunately this is not possible
because the linker does not leave it in a usable state.

However we can do better by first computing the list of all candidates
per Module, and only then load the source Module and import all the
function we need for it.

The trick to process callees is to materialize function in the source
module when building the list of function to import, and inspect them
in their source module, collecting the list of callees for each
callee.

When we move the the actual import, we will import from each source
module exactly once. Each source module is loaded exactly once.
The only drawback it that it requires to have all the lazy-loaded
source Module in memory at the same time.

Currently this patch already improves considerably the link time,
a multithreaded link of llvm-dis on my laptop was:

  real  1m12.175s  user  6m32.430s sys  0m10.529s

and is now:

  real  0m40.697s  user  2m10.237s sys  0m4.375s

Note: this is the full link time (linker+Import+Optimizer+CodeGen)

Differential Revision: http://reviews.llvm.org/D15178

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 255100
2015-12-09 08:17:35 +00:00
Mehdi Amini 5411d0510c Fix/Improve Debug print in FunctionImport pass
From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 255071
2015-12-08 23:04:19 +00:00
Mehdi Amini d16c8065ff Remove caching in FunctionImport: a Module can't be reused after being linked from
The Linker destroys the source module (API change coming to make it explicit)

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 255064
2015-12-08 22:39:40 +00:00
Teresa Johnson 5fcbdb717c [ThinLTO] Support for specifying function index from pass manager
Summary:
Add a field on the PassManagerBuilder that clang or gold can use to pass
down a pointer to the function index in memory to use for importing when
the ThinLTO backend is triggered. Add support to supply this to the
function import pass.

Reviewers: joker.eph, dexonsmith

Subscribers: davidxl, llvm-commits, joker.eph

Differential Revision: http://reviews.llvm.org/D15024

llvm-svn: 254926
2015-12-07 19:21:11 +00:00
Mehdi Amini 311fef6ea5 clang-format FunctionImport after refactoring (NFC)
From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 254585
2015-12-03 02:58:14 +00:00
Mehdi Amini c8c551701e Refactor FunctionImporter::importFunctions with a helper function to process the Worklist (NFC)
This precludes some more functional changes to perform bulk imports.

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 254583
2015-12-03 02:37:33 +00:00
Mehdi Amini ffe2e4aae0 Change ModuleLinker to take a set of GlobalValues to import instead of a single one
For efficiency reason, when importing multiple functions for the same Module,
we can avoid reparsing it every time.

Differential Revision: http://reviews.llvm.org/D15102

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 254486
2015-12-02 04:34:28 +00:00
Mehdi Amini a11bdc8ef7 Modify FunctionImport to take a callback to load modules
When linking static archive, there is no individual module files to
load. Instead they can be mmap'ed and could be initialized from a
buffer directly. The callback provide flexibility to override the
scheme for loading module from the summary.

Differential Revision: http://reviews.llvm.org/D15101

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 254479
2015-12-02 02:00:29 +00:00
Rafael Espindola 0e309fe860 Use references now that it is natural to do so.
The linker never takes ownership of a module or changes which module it
is refering to, making it natural to use references.

llvm-svn: 254449
2015-12-01 19:50:54 +00:00
Teresa Johnson 430110cc0b [ThinLTO] Wrap dbgs() output in DEBUG macro
Missed in a couple places.

llvm-svn: 254422
2015-12-01 17:12:10 +00:00
Teresa Johnson d582f5b3f8 [ThinLTO] Remove stale comment (NFC)
Stale as of r254036 which added basic profitability check.

llvm-svn: 254421
2015-12-01 16:45:23 +00:00
Teresa Johnson 3930361969 [ThinLTO] Add option to limit importing based on instruction count
Add a simple initial heuristic to control importing based on the number
of instructions recorded in the function's summary. Add option to
control the limit, and test using option.

llvm-svn: 254036
2015-11-24 22:55:46 +00:00
Teresa Johnson d450da3281 [ThinLTO] Refactor function body scan during importing into helper (NFC)
llvm-svn: 254020
2015-11-24 21:15:19 +00:00
Teresa Johnson 130de7af7f [ThinLTO] Enable iterative importing in FunctionImport pass
Analyze imported function bodies and add any new external calls to
the worklist for importing. Currently no controls on the importing
so this will end up importing everything possible in the call tree
below the importing module. Basic profitability checks coming next.

Update test to check for iteratively inlined functions.

llvm-svn: 254011
2015-11-24 19:55:04 +00:00
Teresa Johnson 17626654fd [ThinLTO] Fix FunctionImport alias checking and test
Skip imports for weak_any aliases as well. Fix the test to check
non-import of weak aliases and functions, and import of normal alias.

llvm-svn: 253991
2015-11-24 16:10:43 +00:00
Mehdi Amini 42418aba58 Add a FunctionImporter helper to perform summary-based cross-module function importing
Summary:
This is a helper to perform cross-module import for ThinLTO. Right now
it is importing naively every possible called functions.

Reviewers: tejohnson

Subscribers: dexonsmith, llvm-commits

Differential Revision: http://reviews.llvm.org/D14914

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 253954
2015-11-24 06:07:49 +00:00