Summary:
This is a relatively simple scheme: we use the index emitted in the
bitcode to avoid loading all the global metadata. Instead we load
the index with their position in the bitcode so that we can load each
of them individually. Materializing the global metadata block in this
condition only triggers loading the named metadata, and the ones
referenced from there (transitively). When materializing a function,
metadata from the global block are loaded lazily as they are
referenced.
Two main current limitations are:
1) Global values other than functions are not materialized on demand,
so we need to eagerly load METADATA_GLOBAL_DECL_ATTACHMENT records
(and their transitive dependencies).
2) When we load a single metadata, we don't recurse on the operands,
instead we use a placeholder or a temporary metadata. Unfortunately
tepmorary nodes are very expensive. This is why we don't have it
always enabled and only for importing.
These two limitations can be lifted in a subsequent improvement if
needed.
With this change, the total link time of opt with ThinLTO and Debug
Info enabled is going down from 282s to 224s (~20%).
Reviewers: pcc, tejohnson, dexonsmith
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D28113
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291027 91177308-0d34-0410-b5e6-96231b3b80d8
As per post-commit review for r289993 (D27775), we can only safely
import a type as a decl if it has an Identifier, as the Name alone
is not enough to be unique across modules.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@290915 91177308-0d34-0410-b5e6-96231b3b80d8
This makes it explicit what is the exact list to handle, and it
looks much more easy to manipulate and understand that the
previous custom tracking of min/max to express the range where
to look for.
Differential Revision: https://reviews.llvm.org/D28089
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@290507 91177308-0d34-0410-b5e6-96231b3b80d8
This is pure code motion, will just make it more reusable when I'll
attempt to lazy-load Metadats on-demand.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@290414 91177308-0d34-0410-b5e6-96231b3b80d8
This patch implements PR31013 by introducing a
DIGlobalVariableExpression that holds a pair of DIGlobalVariable and
DIExpression.
Currently, DIGlobalVariables holds a DIExpression. This is not the
best way to model this:
(1) The DIGlobalVariable should describe the source level variable,
not how to get to its location.
(2) It makes it unsafe/hard to update the expressions when we call
replaceExpression on the DIGLobalVariable.
(3) It makes it impossible to represent a global variable that is in
more than one location (e.g., a variable with multiple
DW_OP_LLVM_fragment-s). We also moved away from attaching the
DIExpression to DILocalVariable for the same reasons.
This reapplies r289902 with additional testcase upgrades and a change
to the Bitcode record for DIGlobalVariable, that makes upgrading the
old format unambiguous also for variables without DIExpressions.
<rdar://problem/29250149>
https://llvm.org/bugs/show_bug.cgi?id=31013
Differential Revision: https://reviews.llvm.org/D26769
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@290153 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
When reading the metadata bitcode, create a type declaration when
possible for composite types when we are importing. Doing this in
the bitcode reader saves memory. Also it works naturally in the case
when the type ODR map contains a definition for the same composite type
because it was used in the importing module (buildODRType will
automatically use the existing definition and not create a type
declaration).
For Chromium built with -g2, this reduces the aggregate size of the
generated native object files by 66% (from 31G to 10G). It reduced
the time through the ThinLTO link and backend phases by about 20% on
my machine.
Reviewers: mehdi_amini, dblaikie, aprantl
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D27775
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289993 91177308-0d34-0410-b5e6-96231b3b80d8
This reverts commit 289920 (again).
I forgot to implement a Bitcode upgrade for the case where a DIGlobalVariable
has not DIExpression. Unfortunately it is not possible to safely upgrade
these variables without adding a flag to the bitcode record indicating which
version they are.
My plan of record is to roll the planned follow-up patch that adds a
unit: field to DIGlobalVariable into this patch before recomitting.
This way we only need one Bitcode upgrade for both changes (with a
version flag in the bitcode record to safely distinguish the record
formats).
Sorry for the churn!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289982 91177308-0d34-0410-b5e6-96231b3b80d8
This patch implements PR31013 by introducing a
DIGlobalVariableExpression that holds a pair of DIGlobalVariable and
DIExpression.
Currently, DIGlobalVariables holds a DIExpression. This is not the
best way to model this:
(1) The DIGlobalVariable should describe the source level variable,
not how to get to its location.
(2) It makes it unsafe/hard to update the expressions when we call
replaceExpression on the DIGLobalVariable.
(3) It makes it impossible to represent a global variable that is in
more than one location (e.g., a variable with multiple
DW_OP_LLVM_fragment-s). We also moved away from attaching the
DIExpression to DILocalVariable for the same reasons.
This reapplies r289902 with additional testcase upgrades.
<rdar://problem/29250149>
https://llvm.org/bugs/show_bug.cgi?id=31013
Differential Revision: https://reviews.llvm.org/D26769
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289920 91177308-0d34-0410-b5e6-96231b3b80d8
This patch implements PR31013 by introducing a
DIGlobalVariableExpression that holds a pair of DIGlobalVariable and
DIExpression.
Currently, DIGlobalVariables holds a DIExpression. This is not the
best way to model this:
(1) The DIGlobalVariable should describe the source level variable,
not how to get to its location.
(2) It makes it unsafe/hard to update the expressions when we call
replaceExpression on the DIGLobalVariable.
(3) It makes it impossible to represent a global variable that is in
more than one location (e.g., a variable with multiple
DW_OP_LLVM_fragment-s). We also moved away from attaching the
DIExpression to DILocalVariable for the same reasons.
<rdar://problem/29250149>
https://llvm.org/bugs/show_bug.cgi?id=31013
Differential Revision: https://reviews.llvm.org/D26769
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289902 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
I'm planning on changing the way we load metadata to enable laziness.
I'm getting lost in this gigantic files, and gigantic class that is the bitcode
reader. This is a first toward splitting it in a few coarse components that
are more easily understandable.
Reviewers: pcc, tejohnson
Subscribers: mgorny, llvm-commits, dexonsmith
Differential Revision: https://reviews.llvm.org/D27646
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289461 91177308-0d34-0410-b5e6-96231b3b80d8
