maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

[ThinLTO] Remove imported available externally defs from comdats. 

Summary:
Available externally definitions are considered declarations for the
linker and eventually dropped. As such they are not allowed to be
in comdats. Remove any such imported functions from comdats.

Reviewers: rafael

Subscribers: davidxl, llvm-commits, joker.eph

Differential Revision: http://reviews.llvm.org/D16120

llvm-svn: 260122
This commit is contained in:
Teresa Johnson 2016-02-08 18:47:20 +00:00
parent 73fe6ce118
commit d7e88e515c
3 changed files with 46 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
llvm/lib/Linker/LinkModules.cpp
View File

@ -722,9 +722,21 @@ void ThinLTOGlobalProcessing::processGlobalForThinLTO(GlobalValue &GV) {
GV.setVisibility(GlobalValue::HiddenVisibility);
if (isModuleExporting())
NewExportedValues.insert(&GV);
return;
} else
GV.setLinkage(getLinkage(&GV));
// Remove functions imported as available externally defs from comdats,
// as this is a declaration for the linker, and will be dropped eventually.
// It is illegal for comdats to contain declarations.
auto *GO = dyn_cast_or_null<GlobalObject>(&GV);
if (GO && GO->isDeclarationForLinker() && GO->hasComdat()) {
// The IRMover should not have placed any imported declarations in
// a comdat, so the only declaration that should be in a comdat
// at this point would be a definition imported as available_externally.
assert(GO->hasAvailableExternallyLinkage() &&
"Expected comdat on definition (possibly available external)");
GO->setComdat(nullptr);
}
GV.setLinkage(getLinkage(&GV));
}
void ThinLTOGlobalProcessing::processGlobalsForThinLTO() {

4
llvm/test/Linker/Inputs/funcimport_comdat.ll Normal file
View File

@ -0,0 +1,4 @@
define i32 @main() #0 {
entry:
ret i32 0
}

28
llvm/test/Linker/funcimport_comdat.ll Normal file
View File

@ -0,0 +1,28 @@
; Do setup work for all below tests: generate bitcode and combined index
; RUN: llvm-as -function-summary %s -o %t.bc
; RUN: llvm-as -function-summary %p/Inputs/funcimport_comdat.ll -o %t2.bc
; RUN: llvm-lto -thinlto -o %t3 %t.bc %t2.bc
; Ensure linking of comdat containing external linkage global and function
; removes the imported available_externally defs from comdat.
; RUN: llvm-link %t2.bc -functionindex=%t3.thinlto.bc -import=comdat1_func1:%t.bc -S | FileCheck %s --check-prefix=IMPORTCOMDAT
; IMPORTCOMDAT-NOT: $comdat1 = comdat any
; IMPORTCOMDAT-NOT: comdat($comdat1)
; Ensure linking of comdat containing internal linkage function with alias
; removes the imported and promoted available_externally defs from comdat.
; RUN: llvm-link %t2.bc -functionindex=%t3.thinlto.bc -import=comdat2_func1:%t.bc -S | FileCheck %s --check-prefix=IMPORTCOMDAT2
; IMPORTCOMDAT2-NOT: $comdat2 = comdat any
; IMPORTCOMDAT2-NOT: comdat($comdat2)
$comdat1 = comdat any
@comdat1_glob = global i32 0, comdat($comdat1)
define void @comdat1_func1() comdat($comdat1) {
ret void
}
$comdat2 = comdat any
@comdat2_alias = alias void (), void ()* @comdat2_func1
define internal void @comdat2_func1() comdat($comdat2) {
ret void
}