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clang-p2996/clang/test/CodeGen/thinlto-distributed-cfi-devirt.ll
modimo 20faf78919 [ThinLTO] Add noRecurse and noUnwind thinlink function attribute propagation 
Thinlink provides an opportunity to propagate function attributes across modules, enabling additional propagation opportunities.

This change propagates (currently default off, turn on with `disable-thinlto-funcattrs=1`) noRecurse and noUnwind based off of function summaries of the prevailing functions in bottom-up call-graph order. Testing on clang self-build:
1. There's a 35-40% increase in noUnwind functions due to the additional propagation opportunities.
2. Throughput is measured at 10-15% increase in thinlink time which itself is 1.5% of E2E link time.

Implementation-wise this adds the following summary function attributes:
1. noUnwind: function is noUnwind
2. mayThrow: function contains a non-call instruction that `Instruction::mayThrow` returns true on (e.g. windows SEH instructions)
3. hasUnknownCall: function contains calls that don't make it into the summary call-graph thus should not be propagated from (e.g. indirect for now, could add no-opt functions as well)

Testing:
Clang self-build passes and 2nd stage build passes check-all
ninja check-all with newly added tests passing

Reviewed By: tejohnson

Differential Revision: https://reviews.llvm.org/D36850
2021-09-27 12:28:07 -07:00

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; REQUIRES: x86-registered-target
; Backend test for distribute ThinLTO with CFI.
; It additionally enables -fwhole-program-vtables to get more information in
; TYPE_IDs of GLOBALVAL_SUMMARY_BLOCK.
; RUN: opt -thinlto-bc -thinlto-split-lto-unit -o %t.o %s
; FIXME: Fix machine verifier issues and remove -verify-machineinstrs=0. PR39436.
; RUN: llvm-lto2 run -thinlto-distributed-indexes -disable-thinlto-funcattrs=0 %t.o \
; RUN: -whole-program-visibility \
; RUN: -verify-machineinstrs=0 \
; RUN: -o %t2.index \
; 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,_ZTV1B, \
; RUN: -r=%t.o,_ZTV1C, \
; RUN: -r=%t.o,_ZN1A1nEi, \
; RUN: -r=%t.o,_ZN1B1fEi, \
; RUN: -r=%t.o,_ZN1C1fEi, \
; RUN: -r=%t.o,_ZTV1B,px \
; RUN: -r=%t.o,_ZTV1C,px
; Ensure that typeids are in the index.
; RUN: llvm-bcanalyzer -dump %t.o.thinlto.bc | FileCheck %s
; CHECK-LABEL: <GLOBALVAL_SUMMARY_BLOCK
; CHECK: <TYPE_ID op0=0 op1=6 op2=4 op3=7 op4=0 op5=0 op6=0 op7=0 op8=0 op9=2 op10=6 op11=0 op12=0 op13=8 op14=1 op15=6 op16=9 op17=0/>
; CHECK-LABEL: </GLOBALVAL_SUMMARY_BLOCK
; CHECK-LABEL: <STRTAB_BLOCK
; CHECK: blob data = '_ZTS1A_ZN1A1nEi'
; CHECK-LABEL: </STRTAB_BLOCK
; RUN: llvm-dis %t.o.thinlto.bc -o - | FileCheck %s --check-prefix=CHECK-DIS
; Round trip it through llvm-as
; RUN: llvm-dis %t.o.thinlto.bc -o - | llvm-as -o - | llvm-dis -o - | FileCheck %s --check-prefix=CHECK-DIS
; CHECK-DIS: ^0 = module: (path: "{{.*}}thinlto-distributed-cfi-devirt.ll.tmp.o", hash: ({{.*}}, {{.*}}, {{.*}}, {{.*}}, {{.*}}))
; CHECK-DIS: ^1 = gv: (guid: 8346051122425466633, summaries: (function: (module: ^0, flags: (linkage: external, visibility: default, notEligibleToImport: 0, live: 1, dsoLocal: 0, canAutoHide: 0), insts: 18, funcFlags: (readNone: 0, readOnly: 0, noRecurse: 0, returnDoesNotAlias: 0, noInline: 0, alwaysInline: 0, noUnwind: 0, mayThrow: 0, hasUnknownCall: 1), typeIdInfo: (typeTests: (^2), typeCheckedLoadVCalls: (vFuncId: (^2, offset: 8), vFuncId: (^2, offset: 0))))))
; CHECK-DIS: ^2 = typeid: (name: "_ZTS1A", summary: (typeTestRes: (kind: allOnes, sizeM1BitWidth: 7), wpdResolutions: ((offset: 0, wpdRes: (kind: branchFunnel)), (offset: 8, wpdRes: (kind: singleImpl, singleImplName: "_ZN1A1nEi"))))) ; guid = 7004155349499253778
; RUN: %clang_cc1 -triple x86_64-grtev4-linux-gnu \
; RUN: -emit-obj -fthinlto-index=%t.o.thinlto.bc -O2 -Rpass=wholeprogramdevirt \
; RUN: -emit-llvm -o - -x ir %t.o 2>&1 | FileCheck %s --check-prefixes=CHECK-IR --check-prefixes=REMARKS
; Check that the devirtualization is suppressed via -wholeprogramdevirt-skip
; RUN: %clang_cc1 -triple x86_64-grtev4-linux-gnu -mllvm -wholeprogramdevirt-skip=_ZN1A1nEi \
; RUN: -emit-obj -fthinlto-index=%t.o.thinlto.bc -O2 -Rpass=wholeprogramdevirt \
; RUN: -emit-llvm -o - -x ir %t.o 2>&1 | FileCheck %s --check-prefixes=SKIP-IR --check-prefixes=SKIP-REMARKS
; REMARKS: single-impl: devirtualized a call to _ZN1A1nEi
; SKIP-REMARKS-NOT: single-impl
; Check that backend does not fail generating native code.
; RUN: %clang_cc1 -triple x86_64-grtev4-linux-gnu \
; RUN: -emit-obj -fthinlto-index=%t.o.thinlto.bc -O2 \
; RUN: -o %t.native.o -x ir %t.o
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 }
@_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
; CHECK-IR-LABEL: define i32 @test
define i32 @test(%struct.A* %obj, i32 %a) {
entry:
%0 = bitcast %struct.A* %obj to i8**
%vtable5 = load i8*, i8** %0
%1 = tail call { i8*, i1 } @llvm.type.checked.load(i8* %vtable5, i32 8, metadata !"_ZTS1A")
%2 = extractvalue { i8*, i1 } %1, 1
br i1 %2, label %cont, label %trap
trap:
tail call void @llvm.trap()
unreachable
cont:
%3 = extractvalue { i8*, i1 } %1, 0
%4 = bitcast i8* %3 to i32 (%struct.A*, i32)*
; Check that the call was devirtualized.
; CHECK-IR: %call = tail call i32 @_ZN1A1nEi
; SKIP-IR-NOT: %call = tail call i32 @_ZN1A1nEi
%call = tail call i32 %4(%struct.A* nonnull %obj, i32 %a)
%vtable16 = load i8*, i8** %0
%5 = tail call { i8*, i1 } @llvm.type.checked.load(i8* %vtable16, i32 0, metadata !"_ZTS1A")
%6 = extractvalue { i8*, i1 } %5, 1
br i1 %6, label %cont2, label %trap
cont2:
%7 = extractvalue { i8*, i1 } %5, 0
%8 = bitcast i8* %7 to i32 (%struct.A*, i32)*
; Check that traps are conditional. Invalid TYPE_ID can cause
; unconditional traps.
; CHECK-IR: br i1 {{.*}}, label %trap
; We still have to call it as virtual.
; CHECK-IR: %call3 = tail call i32 %7
%call3 = tail call i32 %8(%struct.A* nonnull %obj, i32 %call)
ret i32 %call3
}
; CHECK-IR-LABEL: ret i32
; CHECK-IR-LABEL: }
declare { i8*, i1 } @llvm.type.checked.load(i8*, i32, metadata)
declare void @llvm.trap()
declare i32 @_ZN1B1fEi(%struct.B* %this, i32 %a)
declare i32 @_ZN1A1nEi(%struct.A* %this, i32 %a)
declare i32 @_ZN1C1fEi(%struct.C* %this, i32 %a)
!0 = !{i64 16, !"_ZTS1A"}
!1 = !{i64 16, !"_ZTS1B"}
!2 = !{i64 16, !"_ZTS1C"}
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