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clang-p2996/clang/test/CodeGen/thinlto-distributed-cfi-devirt.ll
Mingming Liu dda73336ad [ThinLTO]Record import type in GlobalValueSummary::GVFlags (#87597) 
The motivating use case is to support import the function declaration
across modules to construct call graph edges for indirect calls [1]
when importing the function definition costs too much compile time
(e.g., the function is too large has no `noinline` attribute).
1. Currently, when the compiled IR module doesn't have a function
definition but its postlink combined summary contains the function
summary or a global alias summary with this function as aliasee, the
function definition will be imported from source module by IRMover. The
implementation is in FunctionImporter::importFunctions [2]
2. In order for FunctionImporter to import a declaration of a function,
both function summary and alias summary need to carry the def / decl
state. Specifically, all existing summary fields doesn't differ across
import modules, but the def / decl state of is decided by
`<ImportModule, Function>`.

This change encodes the def/decl state in `GlobalValueSummary::GVFlags`.

In the subsequent changes
1. The indexing step `computeImportForModule` [3]
will compute the set of definitions and the set of declarations for each
module, and passing on the information to bitcode writer.
2. Bitcode writer will look up the def/decl state and sets the state
when it writes out the flag value. This is demonstrated in
https://github.com/llvm/llvm-project/pull/87600
3. Function importer will read the def/decl state when reading the
combined summary to figure out two sets of global values, and IRMover
will be updated to import the declaration (aka linkGlobalValuePrototype [4])
into the destination module.

- The next change is https://github.com/llvm/llvm-project/pull/87600

[1] mentioned in rfc https://discourse.llvm.org/t/rfc-for-better-call-graph-sort-build-a-more-complete-call-graph-by-adding-more-indirect-call-edges/74029#support-cross-module-function-declaration-import-5
[2] 3b337242ee/llvm/lib/Transforms/IPO/FunctionImport.cpp (L1608-L1764)
[3] 3b337242ee/llvm/lib/Transforms/IPO/FunctionImport.cpp (L856)
[4] 3b337242ee/llvm/lib/Linker/IRMover.cpp (L605)
2024-04-10 19:46:01 -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
; RUN: llvm-lto2 run -thinlto-distributed-indexes -disable-thinlto-funcattrs=0 %t.o \
; RUN: -whole-program-visibility \
; 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, importType: definition), insts: 18, funcFlags: (readNone: 0, readOnly: 0, noRecurse: 0, returnDoesNotAlias: 0, noInline: 0, alwaysInline: 0, noUnwind: 0, mayThrow: 0, hasUnknownCall: 1, mustBeUnreachable: 0), 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 {{%[0-9]+}}
%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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