llvm-project/llvm
Adrian Prantl 25a7174e7a Move the complex address expression out of DIVariable and into an extra
argument of the llvm.dbg.declare/llvm.dbg.value intrinsics.

Previously, DIVariable was a variable-length field that has an optional
reference to a Metadata array consisting of a variable number of
complex address expressions. In the case of OpPiece expressions this is
wasting a lot of storage in IR, because when an aggregate type is, e.g.,
SROA'd into all of its n individual members, the IR will contain n copies
of the DIVariable, all alike, only differing in the complex address
reference at the end.

By making the complex address into an extra argument of the
dbg.value/dbg.declare intrinsics, all of the pieces can reference the
same variable and the complex address expressions can be uniqued across
the CU, too.
Down the road, this will allow us to move other flags, such as
"indirection" out of the DIVariable, too.

The new intrinsics look like this:
declare void @llvm.dbg.declare(metadata %storage, metadata %var, metadata %expr)
declare void @llvm.dbg.value(metadata %storage, i64 %offset, metadata %var, metadata %expr)

This patch adds a new LLVM-local tag to DIExpressions, so we can detect
and pretty-print DIExpression metadata nodes.

What this patch doesn't do:

This patch does not touch the "Indirect" field in DIVariable; but moving
that into the expression would be a natural next step.

http://reviews.llvm.org/D4919
rdar://problem/17994491

Thanks to dblaikie and dexonsmith for reviewing this patch!

llvm-svn: 218778
2014-10-01 17:55:39 +00:00
..
autoconf Delete support for AuroraUX. 2014-08-14 15:15:09 +00:00
bindings Reinstate "Nuke the old JIT." 2014-09-02 22:28:02 +00:00
cmake Add LLVM_ENABLE_MODULES flag to CMake to enable building with C++ modules. 2014-09-26 22:40:15 +00:00
docs Move the complex address expression out of DIVariable and into an extra 2014-10-01 17:55:39 +00:00
examples Add doInitialization/doFinalization to DataLayoutPass. 2014-09-10 21:27:43 +00:00
include Move the complex address expression out of DIVariable and into an extra 2014-10-01 17:55:39 +00:00
lib Move the complex address expression out of DIVariable and into an extra 2014-10-01 17:55:39 +00:00
projects [cmake] Use the external project machinery for libcxxabi so that it can 2014-07-25 10:27:40 +00:00
test Move the complex address expression out of DIVariable and into an extra 2014-10-01 17:55:39 +00:00
tools llvm-cov/CoverageReport.cpp: Quick fix for msvcrt, since width specifier "z" is unavailable. 2014-10-01 00:29:26 +00:00
unittests Move the complex address expression out of DIVariable and into an extra 2014-10-01 17:55:39 +00:00
utils [AVX512] Added intrinsics for VPCMPEQB and VPCMPEQW. 2014-09-30 11:32:22 +00:00
.arcconfig
.clang-format
.clang-tidy Add .clang-tidy configuration file to provide LLVM-optimized defaults for 2014-09-08 13:30:00 +00:00
.gitignore
CMakeLists.txt Add LLVM_ENABLE_MODULES flag to CMake to enable building with C++ modules. 2014-09-26 22:40:15 +00:00
CODE_OWNERS.TXT Add Tom Stellard's role as 3.5 release manager. 2014-09-12 08:07:31 +00:00
CREDITS.TXT Rise from the dead and update personal info 2014-08-25 17:51:04 +00:00
LICENSE.TXT
LLVMBuild.txt
Makefile
Makefile.common
Makefile.config.in Track clang r213171 2014-07-16 16:50:34 +00:00
Makefile.rules Revert my earlier change to add "all" as a dependency to check. In 2014-09-19 18:44:27 +00:00
README.txt
configure Delete support for AuroraUX. 2014-08-14 15:15:09 +00:00
llvm.spec.in

README.txt

Low Level Virtual Machine (LLVM)
================================

This directory and its subdirectories contain source code for the Low Level
Virtual Machine, a toolkit for the construction of highly optimized compilers,
optimizers, and runtime environments.

LLVM is open source software. You may freely distribute it under the terms of
the license agreement found in LICENSE.txt.

Please see the documentation provided in docs/ for further
assistance with LLVM, and in particular docs/GettingStarted.rst for getting
started with LLVM and docs/README.txt for an overview of LLVM's
documentation setup.

If you're writing a package for LLVM, see docs/Packaging.rst for our
suggestions.