RPCS3/llvm-mirror
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-11-26 12:50:30 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

[ThinLTO] Disable "Always import constants" due to compile time issues

Browse Source 
Summary:
Disable the always importing of constants introduced in D70404 by
default under a new internal option, since it is causing order of
magnitude compile time regressions during the thin link. Will continue
investigating why the regressions occur.

Reviewers: evgeny777, wmi

Subscribers: mehdi_amini, inglorion, hiraditya, steven_wu, dexonsmith, arphaman, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D73724
This commit is contained in:
Teresa Johnson 2020-01-30 09:56:43 -08:00
parent 7242e653d2
commit c96a29c643
3 changed files with 11 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
lib/IR/ModuleSummaryIndex.cpp
View File

@ -31,6 +31,12 @@ static cl::opt<bool> PropagateAttrs("propagate-attrs", cl::init(true),
cl::Hidden,
cl::desc("Propagate attributes in index"));
// FIXME: Enable again when thin link compile time regressions understood and
// addressed
static cl::opt<bool> ImportConstantsWithRefs(
"import-constants-with-refs", cl::init(false), cl::Hidden,
cl::desc("Import constant global variables with references"));
FunctionSummary FunctionSummary::ExternalNode =
FunctionSummary::makeDummyFunctionSummary({});
@ -221,8 +227,8 @@ bool ModuleSummaryIndex::canImportGlobalVar(GlobalValueSummary *S,
// c) Link error (external declaration with internal definition).
// However we do not promote objects referenced by writeonly GV
// initializer by means of converting it to 'zeroinitializer'
return !GVS->isConstant() && !isReadOnly(GVS) && !isWriteOnly(GVS) &&
GVS->refs().size();
return !(ImportConstantsWithRefs && GVS->isConstant()) &&
!isReadOnly(GVS) && !isWriteOnly(GVS) && GVS->refs().size();
};
auto *GVS = cast<GlobalVarSummary>(S->getBaseObject());

1
test/ThinLTO/X86/import-constant.ll
View File

@ -4,6 +4,7 @@
; RUN: opt -thinlto-bc %s -o %t1.bc
; RUN: opt -thinlto-bc %p/Inputs/import-constant.ll -o %t2.bc
; RUN: llvm-lto2 run -save-temps %t1.bc %t2.bc -o %t-out \
; RUN: -import-constants-with-refs \
; RUN: -r=%t1.bc,main,plx \
; RUN: -r=%t1.bc,_Z6getObjv,l \
; RUN: -r=%t2.bc,_Z6getObjv,pl \

4
test/ThinLTO/X86/referenced_by_constant.ll
View File

@ -7,14 +7,14 @@
; referenced constant objects. There is stll a room for improvement: we
; can make a local copy of someglobal and someglobal2 because they are both
; 'unnamed_addr' constants. This should eventually be done as well.
; RUN: llvm-lto -thinlto-action=import %t.bc -thinlto-index=%t3.bc -o - | llvm-dis -o - | FileCheck %s --check-prefix=IMPORT
; RUN: llvm-lto -thinlto-action=import -import-constants-with-refs %t.bc -thinlto-index=%t3.bc -o - | llvm-dis -o - | FileCheck %s --check-prefix=IMPORT
; IMPORT: @someglobal.llvm.0 = available_externally hidden unnamed_addr constant i8* bitcast (void ()* @referencedbyglobal to i8*)
; IMPORT: @someglobal2.llvm.0 = available_externally hidden unnamed_addr constant i8* bitcast (void ()* @localreferencedbyglobal.llvm.0 to i8*)
; IMPORT: define available_externally void @bar()
; Check the export side: we currently only export bar(), which causes
; @someglobal and @someglobal2 to be promoted (see above).
; RUN: llvm-lto -thinlto-action=promote %t2.bc -thinlto-index=%t3.bc -o - | llvm-dis -o - | FileCheck %s --check-prefix=EXPORT
; RUN: llvm-lto -thinlto-action=promote -import-constants-with-refs %t2.bc -thinlto-index=%t3.bc -o - | llvm-dis -o - | FileCheck %s --check-prefix=EXPORT
; EXPORT: @someglobal.llvm.0 = hidden unnamed_addr constant
; EXPORT: @someglobal2.llvm.0 = hidden unnamed_addr constant
; EXPORT: define void @referencedbyglobal()