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Differential D34450

bug33527 - Linker::LinkOnlyNeeded should import AppendingLinkage globals (release_40)
AbandonedPublic

Authored by belleyb on Jun 21 2017, 7:25 AM.

Details

Reviewers
pcc
tejohnson
Summary
  • Linker::LinkOnlyNeeded should always import globals with AppendingLinkage when used in Full-LTO / non-performing-import mode.
  • This the patch against the release_40 branch; 4.0.1-rc2 / revision 304242 to be exact. There's also a review for a fix in trunk. See: https://reviews.llvm.org/D34448

See: https://bugs.llvm.org/show_bug.cgi?id=33527

Diff Detail

Event Timeline

belleyb created this revision.Jun 21 2017, 7:25 AM
Herald added subscribers: eraman, mehdi_amini. · View Herald TranscriptJun 21 2017, 7:26 AM
belleyb edited the summary of this revision. (Show Details)Jun 21 2017, 7:36 AM
belleyb edited the summary of this revision. (Show Details)Jun 26 2017, 5:07 AM
mehdi_amini added inline comments.Jun 26 2017, 9:09 AM
unittests/Linker/LinkModulesTest.cpp
939 ↗(On Diff #103373)

Can this be tested with llvm-lto instead of a gtest? That's the preferred way of testing.

belleyb added inline comments.Jun 26 2017, 9:49 AM
unittests/Linker/LinkModulesTest.cpp
939 ↗(On Diff #103373)

No problem. I'll do that.

pcc added inline comments.Jun 26 2017, 9:53 AM
unittests/Linker/LinkModulesTest.cpp
939 ↗(On Diff #103373)

You mean llvm-link, right?

belleyb updated this revision to Diff 104142.Jun 27 2017, 5:01 AM

Converted tests to use lit, llvm-link and FileCheck instead of being written as unit tests

belleyb added inline comments.Jun 27 2017, 5:35 AM
lib/Linker/LinkModules.cpp
358

This extra checks at line 357 and 586 are the fix. Without it, the tests below are failing.

The rest of the changes around is only to make the code more readable, allowing me to better document the intent,

test/Linker/only-needed-compiler-used.ll
8

The linker emits the references to the global variables in a different ordering when the --only-needed is used. This explains the use of the DAG FileCheck option below.

test/Linker/only-needed-ctors2.ll
4

Note that the test case requires at one of the -internalize or -only-needed flag. Else, a link error is generated about func1 being defined twice. This explains why this particular test case has only 3 runs, instead of 4, like most of the other ones.

test/Linker/only-needed-ctors4.ll
4

Note that the test case requires at one of the -internalize or -only-needed flag. Else, a link error is generated about func1 being defined twice. This explains why this particular test case has only 3 runs, instead of 4, like most of the other ones.

test/Linker/only-needed-dtors2.ll
4

Note that the test case requires at one of the -internalize or -only-needed flag. Else, a link error is generated about func1 being defined twice. This explains why this particular test case has only 3 runs, instead of 4, like most of the other ones.

test/Linker/only-needed-dtors4.ll
4

Note that the test case requires at one of the -internalize or -only-needed flag. Else, a link error is generated about func1 being defined twice. This explains why this particular test case has only 3 runs, instead of 4, like most of the other ones.

test/Linker/only-needed-used.ll
8

The linker emits the references to the global variables in a different ordering when the --only-needed is used. This explains the use of the DAG FileCheck option below.

10

This test gives a different result in the release_40 branch than it does in trunk (5.0). I don't know which is correct. I just noticed the difference.

In trunk, the used variables always have global linkage and never internal global linkage, even when the -internalize flag is used. See: https://reviews.llvm.org/D34448

tejohnson edited edge metadata.Jun 27 2017, 8:10 AM

See comments on D34448

belleyb added a comment.Jun 27 2017, 5:13 PM

I will update this code review once https://reviews.llvm.org/D34448 is approved and submitted.

belleyb added a comment.Aug 10 2017, 5:40 AM

Abandoning this review. The fix has been submitted to the LLVM trunk (6.0 at this time) as r310522. Moreover, we will soon move to LLVM 5.0...

belleyb abandoned this revision.Aug 10 2017, 5:41 AM

Revision Contents

Diff 104142

lib/LTO/ThinLTOCodeGenerator.cpp

Show All 28 Lines
#include "llvm/Bitcode/BitcodeWriterPass.h" #include "llvm/Bitcode/BitcodeWriterPass.h"
#include "llvm/ExecutionEngine/ObjectMemoryBuffer.h" #include "llvm/ExecutionEngine/ObjectMemoryBuffer.h"
#include "llvm/IR/DiagnosticPrinter.h" #include "llvm/IR/DiagnosticPrinter.h"
#include "llvm/IR/LLVMContext.h" #include "llvm/IR/LLVMContext.h"
#include "llvm/IR/LegacyPassManager.h" #include "llvm/IR/LegacyPassManager.h"
#include "llvm/IR/Mangler.h" #include "llvm/IR/Mangler.h"
#include "llvm/IRReader/IRReader.h" #include "llvm/IRReader/IRReader.h"
#include "llvm/LTO/LTO.h" #include "llvm/LTO/LTO.h"
#include "llvm/Linker/Linker.h"
#include "llvm/MC/SubtargetFeature.h" #include "llvm/MC/SubtargetFeature.h"
#include "llvm/Object/IRObjectFile.h" #include "llvm/Object/IRObjectFile.h"
#include "llvm/Object/ModuleSummaryIndexObjectFile.h" #include "llvm/Object/ModuleSummaryIndexObjectFile.h"
#include "llvm/Support/CachePruning.h" #include "llvm/Support/CachePruning.h"
#include "llvm/Support/Debug.h" #include "llvm/Support/Debug.h"
#include "llvm/Support/Error.h" #include "llvm/Support/Error.h"
#include "llvm/Support/Path.h" #include "llvm/Support/Path.h"
#include "llvm/Support/SHA1.h" #include "llvm/Support/SHA1.h"
▲ Show 20 Lines • Show All 1,010 Lines • Show Last 20 Lines

lib/Linker/LinkModules.cpp

Show First 20 Lines • Show All 347 Lines • ▼ Show 20 Lines assert(Dest.hasExternalLinkage() && Src.hasExternalLinkage() &&
"Unexpected linkage type!"); "Unexpected linkage type!");
return emitError("Linking globals named '" + Src.getName() + return emitError("Linking globals named '" + Src.getName() +
"': symbol multiply defined!"); "': symbol multiply defined!");
} }
bool ModuleLinker::linkIfNeeded(GlobalValue &GV) { bool ModuleLinker::linkIfNeeded(GlobalValue &GV) {
GlobalValue *DGV = getLinkedToGlobal(&GV); GlobalValue *DGV = getLinkedToGlobal(&GV);
if (shouldLinkOnlyNeeded() && !(DGV && DGV->isDeclaration())) if (shouldLinkOnlyNeeded()) {
// Always import variables with appending linkage.
if (!GV.hasAppendingLinkage()) {
belleybAuthorUnsubmitted
Not Done
ReplyInline Actions

This extra checks at line 357 and 586 are the fix. Without it, the tests below are failing.

The rest of the changes around is only to make the code more readable, allowing me to better document the intent,

belleyb: This extra checks at line 357 and 586 are the fix. Without it, the tests below are failing.
// Don't import globals unless they are referenced by the destination
// module.
if (!DGV)
return false;
// Don't import globals that are already defined in the destination module
if (!DGV->isDeclaration())
return false; return false;
}
}
if (DGV && !GV.hasLocalLinkage() && !GV.hasAppendingLinkage()) { if (DGV && !GV.hasLocalLinkage() && !GV.hasAppendingLinkage()) {
auto *DGVar = dyn_cast<GlobalVariable>(DGV); auto *DGVar = dyn_cast<GlobalVariable>(DGV);
auto *SGVar = dyn_cast<GlobalVariable>(&GV); auto *SGVar = dyn_cast<GlobalVariable>(&GV);
if (DGVar && SGVar) { if (DGVar && SGVar) {
if (DGVar->isDeclaration() && SGVar->isDeclaration() && if (DGVar->isDeclaration() && SGVar->isDeclaration() &&
(!DGVar->isConstant() || !SGVar->isConstant())) { (!DGVar->isConstant() || !SGVar->isConstant())) {
DGVar->setConstant(false); DGVar->setConstant(false);
▲ Show 20 Lines • Show All 202 Lines • ▼ Show 20 Lines for (GlobalValue *GV2 : LazyComdatMembers[SC]) {
return true; return true;
if (LinkFromSrc) if (LinkFromSrc)
ValuesToLink.insert(GV2); ValuesToLink.insert(GV2);
} }
} }
if (shouldInternalizeLinkedSymbols()) { if (shouldInternalizeLinkedSymbols()) {
for (GlobalValue *GV : ValuesToLink) for (GlobalValue *GV : ValuesToLink)
if (!GV->hasAppendingLinkage()) {
Internalize.insert(GV->getName()); Internalize.insert(GV->getName());
} }
}
// FIXME: Propagate Errors through to the caller instead of emitting // FIXME: Propagate Errors through to the caller instead of emitting
// diagnostics. // diagnostics.
bool HasErrors = false; bool HasErrors = false;
if (Error E = Mover.move(std::move(SrcM), ValuesToLink.getArrayRef(), if (Error E = Mover.move(std::move(SrcM), ValuesToLink.getArrayRef(),
[this](GlobalValue &GV, IRMover::ValueAdder Add) { [this](GlobalValue &GV, IRMover::ValueAdder Add) {
addLazyFor(GV, Add); addLazyFor(GV, Add);
}, },
▲ Show 20 Lines • Show All 50 Lines • Show Last 20 Lines

test/Linker/Inputs/only-needed-compiler-used.src.ll

  • This file was added.
@used1 = global i8 4
@used2 = global i32 123
@llvm.compiler.used = appending global [2 x i8*] [
i8* @used1,
i8* bitcast (i32* @used2 to i8*)
], section "llvm.metadata"

test/Linker/Inputs/only-needed-ctors.src.a.ll

  • This file was added.
define internal void @ctor1() {
call void @func1()
ret void
}
define internal void @ctor2() {
ret void
}
define void @func1() {
ret void
}
@llvm.global_ctors = appending global[2 x{i32, void() *, i8 * }] [
{i32, void() *, i8 * } { i32 2, void() *@ctor1, i8 *null},
{i32, void() *, i8 * } { i32 7, void() *@ctor2, i8 *null}]

test/Linker/Inputs/only-needed-ctors.src.b.ll

  • This file was added.
define internal void @ctor3() {
call void @func1()
ret void
}
define internal void @ctor4() {
ret void
}
define void @func1() {
ret void
}
@llvm.global_ctors = appending global[2 x{i32, void() *, i8 * }] [
{i32, void() *, i8 * } { i32 1, void() *@ctor3, i8 *null},
{i32, void() *, i8 * } { i32 9, void() *@ctor4, i8 *null}]

test/Linker/Inputs/only-needed-dtors.src.a.ll

  • This file was added.
define internal void @ctor1() {
call void @func1()
ret void
}
define internal void @ctor2() {
ret void
}
define void @func1() {
ret void
}
@llvm.global_dtors = appending global[2 x{i32, void() *, i8 * }] [
{i32, void() *, i8 * } { i32 2, void() *@ctor1, i8 *null},
{i32, void() *, i8 * } { i32 7, void() *@ctor2, i8 *null}]

test/Linker/Inputs/only-needed-dtors.src.b.ll

  • This file was added.
define internal void @ctor3() {
call void @func1()
ret void
}
define internal void @ctor4() {
ret void
}
define void @func1() {
ret void
}
@llvm.global_dtors = appending global[2 x{i32, void() *, i8 * }] [
{i32, void() *, i8 * } { i32 1, void() *@ctor3, i8 *null},
{i32, void() *, i8 * } { i32 9, void() *@ctor4, i8 *null}]

test/Linker/Inputs/only-needed-used.src.ll

  • This file was added.
@used1 = global i8 4
@used2 = global i32 123
@llvm.used = appending global [2 x i8*] [
i8* @used1,
i8* bitcast (i32* @used2 to i8*)
], section "llvm.metadata"

test/Linker/only-needed-compiler-used.ll

  • This file was added.
; RUN: llvm-link -S %s %p/Inputs/only-needed-compiler-used.src.ll | FileCheck %s --check-prefix=CHECK --check-prefix=NO-INTERNALIZE
; RUN: llvm-link -S -internalize %s %p/Inputs/only-needed-compiler-used.src.ll | FileCheck %s --check-prefix=CHECK --check-prefix=INTERNALIZE
; RUN: llvm-link -S -only-needed %s %p/Inputs/only-needed-compiler-used.src.ll | FileCheck %s --check-prefix=CHECK --check-prefix=NO-INTERNALIZE
; RUN: llvm-link -S -only-needed -internalize %s %p/Inputs/only-needed-compiler-used.src.ll | FileCheck %s --check-prefix=CHECK --check-prefix=INTERNALIZE
; Empty destination module!
belleybAuthorUnsubmitted
Not Done
ReplyInline Actions

The linker emits the references to the global variables in a different ordering when the --only-needed is used. This explains the use of the DAG FileCheck option below.

belleyb: The linker emits the references to the global variables in a different ordering when the `…
; CHECK-DAG: @llvm.compiler.used = appending global [2 x i8*] [i8* @used1, i8* bitcast (i32* @used2 to i8*)], section "llvm.metadata"
; NO-INTERNALIZE-DAG: @used1 = global i8 4
; INTERNALIZE-DAG: @used1 = internal global i8 4
; NO-INTERNALIZE-DAG: @used2 = global i32 123
; INTERNALIZE-DAG: @used2 = internal global i32 123

test/Linker/only-needed-ctors1.ll

  • This file was added.
; RUN: llvm-link -S %s %p/Inputs/only-needed-ctors.src.a.ll | FileCheck %s --check-prefix=CHECK --check-prefix=NO-INTERNALIZE
; RUN: llvm-link -S -internalize %s %p/Inputs/only-needed-ctors.src.a.ll | FileCheck %s --check-prefix=CHECK --check-prefix=INTERNALIZE
; RUN: llvm-link -S -only-needed %s %p/Inputs/only-needed-ctors.src.a.ll | FileCheck %s --check-prefix=CHECK --check-prefix=NO-INTERNALIZE
; RUN: llvm-link -S -only-needed -internalize %s %p/Inputs/only-needed-ctors.src.a.ll | FileCheck %s --check-prefix=CHECK --check-prefix=INTERNALIZE
; Empty destination module!
; CHECK: @llvm.global_ctors = appending global [2 x { i32, void ()*, i8* }] [{ i32, void ()*, i8* } { i32 2, void ()* @ctor1, i8* null }, { i32, void ()*, i8* } { i32 7, void ()* @ctor2, i8* null }]
; CHECK: define internal void @ctor1()
; CHECK: define internal void @ctor2()
; NO-INTERNALIZE: define void @func1()
; INTERNALIZE: define internal void @func1()

test/Linker/only-needed-ctors2.ll

  • This file was added.
; RUN: llvm-link -S -internalize %s %p/Inputs/only-needed-ctors.src.a.ll %p/Inputs/only-needed-ctors.src.b.ll | FileCheck %s --check-prefix=CHECK --check-prefix=INTERNALIZE
; RUN: llvm-link -S -only-needed %s %p/Inputs/only-needed-ctors.src.a.ll %p/Inputs/only-needed-ctors.src.b.ll | FileCheck %s --check-prefix=CHECK --check-prefix=NO-INTERNALIZE
; RUN: llvm-link -S -only-needed -internalize %s %p/Inputs/only-needed-ctors.src.a.ll %p/Inputs/only-needed-ctors.src.b.ll | FileCheck %s --check-prefix=CHECK --check-prefix=INTERNALIZE
belleybAuthorUnsubmitted
Not Done
ReplyInline Actions

Note that the test case requires at one of the -internalize or -only-needed flag. Else, a link error is generated about func1 being defined twice. This explains why this particular test case has only 3 runs, instead of 4, like most of the other ones.

belleyb: Note that the test case requires at one of the `-internalize` or `-only-needed` flag. Else, a…
; Empty destination module!
; CHECK: @llvm.global_ctors = appending global [4 x { i32, void ()*, i8* }] [{ i32, void ()*, i8* } { i32 2, void ()* @ctor1, i8* null }, { i32, void ()*, i8* } { i32 7, void ()* @ctor2, i8* null }, { i32, void ()*, i8* } { i32 1, void ()* @ctor3, i8* null }, { i32, void ()*, i8* } { i32 9, void ()* @ctor4, i8* null }]
; CHECK: define internal void @ctor1()
; CHECK: define internal void @ctor2()
; NO-INTERNALIZE: define void @func1()
; INTERNALIZE: define internal void @func1.{{[0-9]+}}()
; CHECK: define internal void @ctor3()
; CHECK: define internal void @ctor4()
; INTERNALIZE: define internal void @func1()

test/Linker/only-needed-ctors3.ll

  • This file was added.
; RUN: llvm-link -S %s %p/Inputs/only-needed-ctors.src.a.ll | FileCheck %s --check-prefix=CHECK --check-prefix=NO-INTERNALIZE
; RUN: llvm-link -S -internalize %s %p/Inputs/only-needed-ctors.src.a.ll | FileCheck %s --check-prefix=CHECK --check-prefix=INTERNALIZE
; RUN: llvm-link -S -only-needed %s %p/Inputs/only-needed-ctors.src.a.ll | FileCheck %s --check-prefix=CHECK --check-prefix=NO-INTERNALIZE
; RUN: llvm-link -S -only-needed -internalize %s %p/Inputs/only-needed-ctors.src.a.ll | FileCheck %s --check-prefix=CHECK --check-prefix=INTERNALIZE
; Destination module:
define void @foo() {
ret void
}
define internal void @ctor1() {
ret void
}
@llvm.global_ctors = appending global[1 x{i32, void() *, i8 * }] [
{i32, void() *, i8 * } { i32 4, void() *@ctor1, i8 *null}]
; CHECK: @llvm.global_ctors = appending global [3 x { i32, void ()*, i8* }] [{ i32, void ()*, i8* } { i32 4, void ()* @ctor1, i8* null }, { i32, void ()*, i8* } { i32 2, void ()* @ctor1.2, i8* null }, { i32, void ()*, i8* } { i32 7, void ()* @ctor2, i8* null }]
; CHECK: define internal void @ctor1()
; CHECK: define void @foo()
; CHECK: define internal void @ctor1.{{[0-9]+}}()
; CHECK: define internal void @ctor2()
; NO-INTERNALIZE: define void @func1()
; INTERNALIZE: define internal void @func1()

test/Linker/only-needed-ctors4.ll

  • This file was added.
; RUN: llvm-link -S -internalize %s %p/Inputs/only-needed-ctors.src.a.ll %p/Inputs/only-needed-ctors.src.b.ll | FileCheck %s --check-prefix=CHECK --check-prefix=INTERNALIZE
; RUN: llvm-link -S -only-needed %s %p/Inputs/only-needed-ctors.src.a.ll %p/Inputs/only-needed-ctors.src.b.ll | FileCheck %s --check-prefix=CHECK --check-prefix=NO-INTERNALIZE
; RUN: llvm-link -S -only-needed -internalize %s %p/Inputs/only-needed-ctors.src.a.ll %p/Inputs/only-needed-ctors.src.b.ll | FileCheck %s --check-prefix=CHECK --check-prefix=INTERNALIZE
belleybAuthorUnsubmitted
Not Done
ReplyInline Actions

Note that the test case requires at one of the -internalize or -only-needed flag. Else, a link error is generated about func1 being defined twice. This explains why this particular test case has only 3 runs, instead of 4, like most of the other ones.

belleyb: Note that the test case requires at one of the `-internalize` or `-only-needed` flag. Else, a…
; Destination module:
define void @foo() {
ret void
}
define internal void @ctor1() {
ret void
}
@llvm.global_ctors = appending global[1 x{i32, void() *, i8 * }] [
{i32, void() *, i8 * } { i32 4, void() *@ctor1, i8 *null}]
; CHECK: @llvm.global_ctors = appending global [5 x { i32, void ()*, i8* }] [{ i32, void ()*, i8* } { i32 4, void ()* @ctor1, i8* null }, { i32, void ()*, i8* } { i32 2, void ()* @ctor1.2, i8* null }, { i32, void ()*, i8* } { i32 7, void ()* @ctor2, i8* null }, { i32, void ()*, i8* } { i32 1, void ()* @ctor3, i8* null }, { i32, void ()*, i8* } { i32 9, void ()* @ctor4, i8* null }]
; CHECK: define internal void @ctor1()
; CHECK: define void @foo()
; CHECK: define internal void @ctor1.{{[0-9]+}}()
; CHECK: define internal void @ctor2()
; NO-INTERNALIZE: define void @func1()
; INTERNALIZE: define internal void @func1.{{[0-9]+}}()
; CHECK: define internal void @ctor3()
; CHECK: define internal void @ctor4()
; INTERNALIZE: define internal void @func1()

test/Linker/only-needed-dtors1.ll

  • This file was added.
; RUN: llvm-link -S %s %p/Inputs/only-needed-dtors.src.a.ll | FileCheck %s --check-prefix=CHECK --check-prefix=NO-INTERNALIZE
; RUN: llvm-link -S -internalize %s %p/Inputs/only-needed-dtors.src.a.ll | FileCheck %s --check-prefix=CHECK --check-prefix=INTERNALIZE
; RUN: llvm-link -S -only-needed %s %p/Inputs/only-needed-dtors.src.a.ll | FileCheck %s --check-prefix=CHECK --check-prefix=NO-INTERNALIZE
; RUN: llvm-link -S -only-needed -internalize %s %p/Inputs/only-needed-dtors.src.a.ll | FileCheck %s --check-prefix=CHECK --check-prefix=INTERNALIZE
; Empty destination module!
; CHECK: @llvm.global_dtors = appending global [2 x { i32, void ()*, i8* }] [{ i32, void ()*, i8* } { i32 2, void ()* @ctor1, i8* null }, { i32, void ()*, i8* } { i32 7, void ()* @ctor2, i8* null }]
; CHECK: define internal void @ctor1()
; CHECK: define internal void @ctor2()
; NO-INTERNALIZE: define void @func1()
; INTERNALIZE: define internal void @func1()

test/Linker/only-needed-dtors2.ll

  • This file was added.
; RUN: llvm-link -S -internalize %s %p/Inputs/only-needed-dtors.src.a.ll %p/Inputs/only-needed-dtors.src.b.ll | FileCheck %s --check-prefix=CHECK --check-prefix=INTERNALIZE
; RUN: llvm-link -S -only-needed %s %p/Inputs/only-needed-dtors.src.a.ll %p/Inputs/only-needed-dtors.src.b.ll | FileCheck %s --check-prefix=CHECK --check-prefix=NO-INTERNALIZE
; RUN: llvm-link -S -only-needed -internalize %s %p/Inputs/only-needed-dtors.src.a.ll %p/Inputs/only-needed-dtors.src.b.ll | FileCheck %s --check-prefix=CHECK --check-prefix=INTERNALIZE
belleybAuthorUnsubmitted
Not Done
ReplyInline Actions

Note that the test case requires at one of the -internalize or -only-needed flag. Else, a link error is generated about func1 being defined twice. This explains why this particular test case has only 3 runs, instead of 4, like most of the other ones.

belleyb: Note that the test case requires at one of the `-internalize` or `-only-needed` flag. Else, a…
; Empty destination module!
; CHECK: @llvm.global_dtors = appending global [4 x { i32, void ()*, i8* }] [{ i32, void ()*, i8* } { i32 2, void ()* @ctor1, i8* null }, { i32, void ()*, i8* } { i32 7, void ()* @ctor2, i8* null }, { i32, void ()*, i8* } { i32 1, void ()* @ctor3, i8* null }, { i32, void ()*, i8* } { i32 9, void ()* @ctor4, i8* null }]
; CHECK: define internal void @ctor1()
; CHECK: define internal void @ctor2()
; NO-INTERNALIZE: define void @func1()
; INTERNALIZE: define internal void @func1.{{[0-9]+}}()
; CHECK: define internal void @ctor3()
; CHECK: define internal void @ctor4()
; INTERNALIZE: define internal void @func1()

test/Linker/only-needed-dtors3.ll

  • This file was added.
; RUN: llvm-link -S %s %p/Inputs/only-needed-dtors.src.a.ll | FileCheck %s --check-prefix=CHECK
; RUN: llvm-link -S -internalize %s %p/Inputs/only-needed-dtors.src.a.ll | FileCheck %s --check-prefix=CHECK --check-prefix=INTERNALIZE
; RUN: llvm-link -S -only-needed %s %p/Inputs/only-needed-dtors.src.a.ll | FileCheck %s --check-prefix=CHECK
; RUN: llvm-link -S -only-needed -internalize %s %p/Inputs/only-needed-dtors.src.a.ll | FileCheck %s --check-prefix=CHECK --check-prefix=INTERNALIZE
; Destination module:
define void @foo() {
ret void
}
define internal void @ctor1() {
ret void
}
@llvm.global_dtors = appending global[1 x{i32, void() *, i8 * }] [
{i32, void() *, i8 * } { i32 4, void() *@ctor1, i8 *null}]
; CHECK: @llvm.global_dtors = appending global [3 x { i32, void ()*, i8* }] [{ i32, void ()*, i8* } { i32 4, void ()* @ctor1, i8* null }, { i32, void ()*, i8* } { i32 2, void ()* @ctor1.2, i8* null }, { i32, void ()*, i8* } { i32 7, void ()* @ctor2, i8* null }]
; CHECK: define internal void @ctor1()
; CHECK: define void @foo()
; CHECK: define internal void @ctor1.{{[0-9]+}}()
; CHECK: define internal void @ctor2()
; INTERNALIZE: define internal void @func1()

test/Linker/only-needed-dtors4.ll

  • This file was added.
; RUN: llvm-link -S -internalize %s %p/Inputs/only-needed-dtors.src.a.ll %p/Inputs/only-needed-dtors.src.b.ll | FileCheck %s --check-prefix=CHECK --check-prefix=INTERNALIZE
; RUN: llvm-link -S -only-needed %s %p/Inputs/only-needed-dtors.src.a.ll %p/Inputs/only-needed-dtors.src.b.ll | FileCheck %s --check-prefix=CHECK --check-prefix=NO-INTERNALIZE
; RUN: llvm-link -S -only-needed -internalize %s %p/Inputs/only-needed-dtors.src.a.ll %p/Inputs/only-needed-dtors.src.b.ll | FileCheck %s --check-prefix=CHECK --check-prefix=INTERNALIZE
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Note that the test case requires at one of the -internalize or -only-needed flag. Else, a link error is generated about func1 being defined twice. This explains why this particular test case has only 3 runs, instead of 4, like most of the other ones.

belleyb: Note that the test case requires at one of the `-internalize` or `-only-needed` flag. Else, a…
; Destination module:
define void @foo() {
ret void
}
define internal void @ctor1() {
ret void
}
@llvm.global_dtors = appending global[1 x{i32, void() *, i8 * }] [
{i32, void() *, i8 * } { i32 4, void() *@ctor1, i8 *null}]
; CHECK: @llvm.global_dtors = appending global [5 x { i32, void ()*, i8* }] [{ i32, void ()*, i8* } { i32 4, void ()* @ctor1, i8* null }, { i32, void ()*, i8* } { i32 2, void ()* @ctor1.2, i8* null }, { i32, void ()*, i8* } { i32 7, void ()* @ctor2, i8* null }, { i32, void ()*, i8* } { i32 1, void ()* @ctor3, i8* null }, { i32, void ()*, i8* } { i32 9, void ()* @ctor4, i8* null }]
; CHECK: define internal void @ctor1()
; CHECK: define void @foo()
; CHECK: define internal void @ctor1.{{[0-9]+}}()
; CHECK: define internal void @ctor2()
; NO-INTERNALIZE: define void @func1()
; INTERNALIZE: define internal void @func1.{{[0-9]+}}()
; CHECK: define internal void @ctor3()
; CHECK: define internal void @ctor4()
; INTERNALIZE: define internal void @func1()

test/Linker/only-needed-used.ll

  • This file was added.
; RUN: llvm-link -S %s %p/Inputs/only-needed-used.src.ll | FileCheck %s --check-prefix=CHECK --check-prefix=NO-INTERNALIZE
; RUN: llvm-link -S -internalize %s %p/Inputs/only-needed-used.src.ll | FileCheck %s --check-prefix=CHECK --check-prefix=INTERNALIZE
; RUN: llvm-link -S -only-needed %s %p/Inputs/only-needed-used.src.ll | FileCheck %s --check-prefix=CHECK --check-prefix=NO-INTERNALIZE
; RUN: llvm-link -S -only-needed -internalize %s %p/Inputs/only-needed-used.src.ll | FileCheck %s --check-prefix=CHECK --check-prefix=INTERNALIZE
; Empty destination module!
belleybAuthorUnsubmitted
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The linker emits the references to the global variables in a different ordering when the --only-needed is used. This explains the use of the DAG FileCheck option below.

belleyb: The linker emits the references to the global variables in a different ordering when the `…
; CHECK-DAG: @llvm.used = appending global [2 x i8*] [i8* @used1, i8* bitcast (i32* @used2 to i8*)], section "llvm.metadata"
; INTERNALIZE-DAG: @used1 = internal global i8 4
belleybAuthorUnsubmitted
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This test gives a different result in the release_40 branch than it does in trunk (5.0). I don't know which is correct. I just noticed the difference.

In trunk, the used variables always have global linkage and never internal global linkage, even when the -internalize flag is used. See: https://reviews.llvm.org/D34448

belleyb: This test gives a different result in the release_40 branch than it does in trunk (5.0). I…
; NO-INTERNALIZE-DAG: @used1 = global i8 4
; INTERNALIZE-DAG: @used2 = internal global i32 123
; NO-INTERNALIZE-DAG: @used2 = global i32 123