llvm-project/llvm/tools/gold
Teresa Johnson 76a1c1d0ba [ThinLTO] Support for reference graph in per-module and combined summary.
Summary:
This patch adds support for including a full reference graph including
call graph edges and other GV references in the summary.

The reference graph edges can be used to make importing decisions
without materializing any source modules, can be used in the plugin
to make file staging decisions for distributed build systems, and is
expected to have other uses.

The call graph edges are recorded in each function summary in the
bitcode via a list of <CalleeValueIds, StaticCount> tuples when no PGO
data exists, or <CalleeValueId, StaticCount, ProfileCount> pairs when
there is PGO, where the ValueId can be mapped to the function GUID via
the ValueSymbolTable. In the function index in memory, the call graph
edges reference the target via the CalleeGUID instead of the
CalleeValueId.

The reference graph edges are recorded in each summary record with a
list of referenced value IDs, which can be mapped to value GUID via the
ValueSymbolTable.

Addtionally, a new summary record type is added to record references
from global variable initializers. A number of bitcode records and data
structures have been renamed to reflect the newly expanded scope of the
summary beyond functions. More cleanup will follow.

Reviewers: joker.eph, davidxl

Subscribers: joker.eph, llvm-commits

Differential Revision: http://reviews.llvm.org/D17212

llvm-svn: 263275
2016-03-11 18:52:24 +00:00
..
CMakeLists.txt [gold] Consolidate the gold plugin options and actually search for 2015-02-14 09:43:57 +00:00
README.txt Cut the gold plugin README down to size 2013-12-02 14:17:47 +00:00
gold-plugin.cpp [ThinLTO] Support for reference graph in per-module and combined summary. 2016-03-11 18:52:24 +00:00
gold.exports

README.txt

The LLVM Gold LTO Plugin
========================

This directory contains a plugin that is designed to work with binutils
gold linker. At present time, this is not the default linker in
binutils, and the default build of gold does not support plugins.

See docs/GoldPlugin.html for complete build and usage instructions.

NOTE: libLTO and LLVMgold aren't built without PIC because they would fail
to link on x86-64 with a relocation error: PIC and non-PIC can't be combined.
As an alternative to passing --enable-pic, you can use 'make ENABLE_PIC=1' in
your entire LLVM build.