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clang-p2996/llvm/test/ThinLTO/X86/devirt.ll
Teresa Johnson fee0bde4c6 [WPD] Extend checking mode to support fallback to indirect call 
Extend -wholeprogramdevirt-check to support both the existing
trapping mode on an incorrect devirtualization, as well as a new
mode to fallback to an indirect call on a mismatch. The new mode is

The new mode is useful in cases where we want to enable
devirtualization but cannot fully guarantee whole program visibility
(e.g in the case where LTO has been disabled for a small set of objects
that could potentially override virtual methods without having a symbol
reference to anything in the base class including the vtable).

Remove !prof and !callees metadata (which are used by indirect call
promotion) from both the new direct call and the fallback indirect call
(so that we don't perform another round of promotion on the latter).
Also remove it from the direct call in the non-fallback cases, which
was an oversight, although it didn't seem to cause any issues. Add tests
for the metadata removal covering the various cases.

Differential Revision: https://reviews.llvm.org/D121419
2022-03-14 10:16:28 -07:00

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; REQUIRES: x86-registered-target
; Test devirtualization through the thin link and backend.
; Generate split module with summary for hybrid Thin/Regular LTO WPD.
; RUN: opt -thinlto-bc -thinlto-split-lto-unit -o %t.o %s
; Check that we have module flag showing splitting enabled, and that we don't
; generate summary information needed for index-based WPD.
; RUN: llvm-modextract -b -n=0 %t.o -o %t.o.0
; RUN: llvm-dis -o - %t.o.0 | FileCheck %s --check-prefix=ENABLESPLITFLAG --implicit-check-not=vTableFuncs --implicit-check-not=typeidCompatibleVTable
; RUN: llvm-modextract -b -n=1 %t.o -o %t.o.1
; RUN: llvm-dis -o - %t.o.1 | FileCheck %s --check-prefix=ENABLESPLITFLAG --implicit-check-not=vTableFuncs --implicit-check-not=typeidCompatibleVTable
; ENABLESPLITFLAG: !{i32 1, !"EnableSplitLTOUnit", i32 1}
; Generate unsplit module with summary for ThinLTO index-based WPD.
; RUN: opt -thinlto-bc -o %t2.o %s
; Check that we don't have module flag when splitting not enabled for ThinLTO,
; and that we generate summary information needed for index-based WPD.
; RUN: llvm-dis -o - %t2.o | FileCheck %s --check-prefix=NOENABLESPLITFLAG
; NOENABLESPLITFLAG-DAG: !{i32 1, !"EnableSplitLTOUnit", i32 0}
; NOENABLESPLITFLAG-DAG: [[An:\^[0-9]+]] = gv: (name: "_ZN1A1nEi"
; NOENABLESPLITFLAG-DAG: [[Bf:\^[0-9]+]] = gv: (name: "_ZN1B1fEi"
; NOENABLESPLITFLAG-DAG: [[Cf:\^[0-9]+]] = gv: (name: "_ZN1C1fEi"
; NOENABLESPLITFLAG-DAG: [[Dm:\^[0-9]+]] = gv: (name: "_ZN1D1mEi"
; NOENABLESPLITFLAG-DAG: [[B:\^[0-9]+]] = gv: (name: "_ZTV1B", {{.*}} vTableFuncs: ((virtFunc: [[Bf]], offset: 16), (virtFunc: [[An]], offset: 24)), refs: ([[Bf]], [[An]])
; NOENABLESPLITFLAG-DAG: [[C:\^[0-9]+]] = gv: (name: "_ZTV1C", {{.*}} vTableFuncs: ((virtFunc: [[Cf]], offset: 16), (virtFunc: [[An]], offset: 24)), refs: ([[An]], [[Cf]])
; NOENABLESPLITFLAG-DAG: [[D:\^[0-9]+]] = gv: (name: "_ZTV1D", {{.*}} vTableFuncs: ((virtFunc: [[Dm]], offset: 16)), refs: ([[Dm]])
; NOENABLESPLITFLAG-DAG: typeidCompatibleVTable: (name: "_ZTS1A", summary: ((offset: 16, [[B]]), (offset: 16, [[C]])))
; NOENABLESPLITFLAG-DAG: typeidCompatibleVTable: (name: "_ZTS1B", summary: ((offset: 16, [[B]])))
; NOENABLESPLITFLAG-DAG: typeidCompatibleVTable: (name: "_ZTS1C", summary: ((offset: 16, [[C]])))
; Type Id on _ZTV1D should have been promoted
; NOENABLESPLITFLAG-DAG: typeidCompatibleVTable: (name: "1.{{.*}}", summary: ((offset: 16, [[D]])))
; Legacy PM, Index based WPD
; RUN: llvm-lto2 run %t2.o -save-temps -pass-remarks=. \
; RUN: -whole-program-visibility \
; RUN: -o %t3 \
; RUN: -r=%t2.o,test,px \
; RUN: -r=%t2.o,_ZN1A1nEi,p \
; RUN: -r=%t2.o,_ZN1B1fEi,p \
; RUN: -r=%t2.o,_ZN1C1fEi,p \
; RUN: -r=%t2.o,_ZN1D1mEi,p \
; RUN: -r=%t2.o,_ZTV1B,px \
; RUN: -r=%t2.o,_ZTV1C,px \
; RUN: -r=%t2.o,_ZTV1D,px 2>&1 | FileCheck %s --check-prefix=REMARK
; RUN: llvm-dis %t3.1.4.opt.bc -o - | FileCheck %s --check-prefix=CHECK-IR
; Check that we're able to prevent specific function from being
; devirtualized when running index based WPD.
; RUN: llvm-lto2 run %t2.o -save-temps -pass-remarks=. \
; RUN: -whole-program-visibility \
; RUN: -wholeprogramdevirt-skip=_ZN1A1nEi \
; RUN: -o %t3 \
; RUN: -r=%t2.o,test,px \
; RUN: -r=%t2.o,_ZN1A1nEi,p \
; RUN: -r=%t2.o,_ZN1B1fEi,p \
; RUN: -r=%t2.o,_ZN1C1fEi,p \
; RUN: -r=%t2.o,_ZN1D1mEi,p \
; RUN: -r=%t2.o,_ZTV1B,px \
; RUN: -r=%t2.o,_ZTV1C,px \
; RUN: -r=%t2.o,_ZTV1D,px 2>&1 | FileCheck %s --check-prefix=SKIP
; New PM, Index based WPD
; RUN: llvm-lto2 run %t2.o -save-temps -use-new-pm -pass-remarks=. \
; RUN: -whole-program-visibility \
; RUN: -o %t3 \
; RUN: -r=%t2.o,test,px \
; RUN: -r=%t2.o,_ZN1A1nEi,p \
; RUN: -r=%t2.o,_ZN1B1fEi,p \
; RUN: -r=%t2.o,_ZN1C1fEi,p \
; RUN: -r=%t2.o,_ZN1D1mEi,p \
; RUN: -r=%t2.o,_ZTV1B,px \
; RUN: -r=%t2.o,_ZTV1C,px \
; RUN: -r=%t2.o,_ZTV1D,px 2>&1 | FileCheck %s --check-prefix=REMARK
; RUN: llvm-dis %t3.1.4.opt.bc -o - | FileCheck %s --check-prefix=CHECK-IR
; Legacy PM
; FIXME: Fix machine verifier issues and remove -verify-machineinstrs=0. PR39436.
; RUN: llvm-lto2 run %t.o -save-temps -pass-remarks=. \
; RUN: -whole-program-visibility \
; RUN: -verify-machineinstrs=0 \
; RUN: -o %t3 \
; RUN: -r=%t.o,test,px \
; RUN: -r=%t.o,_ZN1A1nEi,p \
; RUN: -r=%t.o,_ZN1B1fEi,p \
; RUN: -r=%t.o,_ZN1C1fEi,p \
; RUN: -r=%t.o,_ZN1D1mEi,p \
; RUN: -r=%t.o,_ZTV1B, \
; RUN: -r=%t.o,_ZTV1C, \
; RUN: -r=%t.o,_ZTV1D, \
; RUN: -r=%t.o,_ZN1A1nEi, \
; RUN: -r=%t.o,_ZN1B1fEi, \
; RUN: -r=%t.o,_ZN1C1fEi, \
; RUN: -r=%t.o,_ZN1D1mEi, \
; RUN: -r=%t.o,_ZTV1B,px \
; RUN: -r=%t.o,_ZTV1C,px \
; RUN: -r=%t.o,_ZTV1D,px 2>&1 | FileCheck %s --check-prefix=REMARK --dump-input=fail
; RUN: llvm-dis %t3.1.4.opt.bc -o - | FileCheck %s --check-prefix=CHECK-IR
; New PM
; FIXME: Fix machine verifier issues and remove -verify-machineinstrs=0. PR39436.
; RUN: llvm-lto2 run %t.o -save-temps -use-new-pm -pass-remarks=. \
; RUN: -whole-program-visibility \
; RUN: -verify-machineinstrs=0 \
; RUN: -o %t3 \
; RUN: -r=%t.o,test,px \
; RUN: -r=%t.o,_ZN1A1nEi,p \
; RUN: -r=%t.o,_ZN1B1fEi,p \
; RUN: -r=%t.o,_ZN1C1fEi,p \
; RUN: -r=%t.o,_ZN1D1mEi,p \
; RUN: -r=%t.o,_ZTV1B, \
; RUN: -r=%t.o,_ZTV1C, \
; RUN: -r=%t.o,_ZTV1D, \
; RUN: -r=%t.o,_ZN1A1nEi, \
; RUN: -r=%t.o,_ZN1B1fEi, \
; RUN: -r=%t.o,_ZN1C1fEi, \
; RUN: -r=%t.o,_ZN1D1mEi, \
; RUN: -r=%t.o,_ZTV1B,px \
; RUN: -r=%t.o,_ZTV1C,px \
; RUN: -r=%t.o,_ZTV1D,px 2>&1 | FileCheck %s --check-prefix=REMARK --dump-input=fail
; RUN: llvm-dis %t3.1.4.opt.bc -o - | FileCheck %s --check-prefix=CHECK-IR
; REMARK-DAG: single-impl: devirtualized a call to _ZN1A1nEi
; REMARK-DAG: single-impl: devirtualized a call to _ZN1D1mEi
; SKIP-NOT: devirtualized a call to _ZN1A1nEi
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-grtev4-linux-gnu"
%struct.A = type { i32 (...)** }
%struct.B = type { %struct.A }
%struct.C = type { %struct.A }
%struct.D = type { i32 (...)** }
@_ZTV1B = constant { [4 x i8*] } { [4 x i8*] [i8* null, i8* undef, i8* bitcast (i32 (%struct.B*, i32)* @_ZN1B1fEi to i8*), i8* bitcast (i32 (%struct.A*, i32)* @_ZN1A1nEi to i8*)] }, !type !0, !type !1
@_ZTV1C = constant { [4 x i8*] } { [4 x i8*] [i8* null, i8* undef, i8* bitcast (i32 (%struct.C*, i32)* @_ZN1C1fEi to i8*), i8* bitcast (i32 (%struct.A*, i32)* @_ZN1A1nEi to i8*)] }, !type !0, !type !2
@_ZTV1D = constant { [3 x i8*] } { [3 x i8*] [i8* null, i8* undef, i8* bitcast (i32 (%struct.D*, i32)* @_ZN1D1mEi to i8*)] }, !type !3
; CHECK-IR-LABEL: define i32 @test
define i32 @test(%struct.A* %obj, %struct.D* %obj2, i32 %a) {
entry:
%0 = bitcast %struct.A* %obj to i8***
%vtable = load i8**, i8*** %0
%1 = bitcast i8** %vtable to i8*
%p = call i1 @llvm.type.test(i8* %1, metadata !"_ZTS1A")
call void @llvm.assume(i1 %p)
%fptrptr = getelementptr i8*, i8** %vtable, i32 1
%2 = bitcast i8** %fptrptr to i32 (%struct.A*, i32)**
%fptr1 = load i32 (%struct.A*, i32)*, i32 (%struct.A*, i32)** %2, align 8
; Check that the call was devirtualized.
; CHECK-IR: %call = tail call i32 @_ZN1A1nEi
; Ensure !prof and !callees metadata for indirect call promotion removed.
; CHECK-IR-NOT: prof
; CHECK-IR-NOT: callees
%call = tail call i32 %fptr1(%struct.A* nonnull %obj, i32 %a), !prof !5, !callees !6
%3 = bitcast i8** %vtable to i32 (%struct.A*, i32)**
%fptr22 = load i32 (%struct.A*, i32)*, i32 (%struct.A*, i32)** %3, align 8
; We still have to call it as virtual.
; CHECK-IR: %call3 = tail call i32 %fptr22
%call3 = tail call i32 %fptr22(%struct.A* nonnull %obj, i32 %call)
%4 = bitcast %struct.D* %obj2 to i8***
%vtable2 = load i8**, i8*** %4
%5 = bitcast i8** %vtable2 to i8*
%p2 = call i1 @llvm.type.test(i8* %5, metadata !4)
call void @llvm.assume(i1 %p2)
%6 = bitcast i8** %vtable2 to i32 (%struct.D*, i32)**
%fptr33 = load i32 (%struct.D*, i32)*, i32 (%struct.D*, i32)** %6, align 8
; Check that the call was devirtualized.
; CHECK-IR: %call4 = tail call i32 @_ZN1D1mEi
%call4 = tail call i32 %fptr33(%struct.D* nonnull %obj2, i32 %call3)
ret i32 %call4
}
; CHECK-IR-LABEL: ret i32
; CHECK-IR-LABEL: }
declare i1 @llvm.type.test(i8*, metadata)
declare void @llvm.assume(i1)
define i32 @_ZN1B1fEi(%struct.B* %this, i32 %a) #0 {
ret i32 0;
}
define i32 @_ZN1A1nEi(%struct.A* %this, i32 %a) #0 {
ret i32 0;
}
define i32 @_ZN1C1fEi(%struct.C* %this, i32 %a) #0 {
ret i32 0;
}
define i32 @_ZN1D1mEi(%struct.D* %this, i32 %a) #0 {
ret i32 0;
}
; Make sure we don't inline or otherwise optimize out the direct calls.
attributes #0 = { noinline optnone }
!0 = !{i64 16, !"_ZTS1A"}
!1 = !{i64 16, !"_ZTS1B"}
!2 = !{i64 16, !"_ZTS1C"}
!3 = !{i64 16, !4}
!4 = distinct !{}
!5 = !{!"VP", i32 0, i64 1, i64 1621563287929432257, i64 1}
!6 = !{i32 (%struct.A*, i32)* @_ZN1A1nEi}
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