Files
clang-p2996/clang/test/CodeGen/thinlto-distributed-cfi.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

75 lines
2.9 KiB
LLVM

; REQUIRES: x86-registered-target
; Backend test for distribute ThinLTO with CFI.
; 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: -o %t2.index \
; RUN: -r=%t.o,test,px \
; RUN: -r=%t.o,_ZTV1B, \
; RUN: -r=%t.o,_ZN1B1fEi, \
; RUN: -r=%t.o,_ZTV1B,px
; Check 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=3 op3=0 op4=0 op5=0 op6=0 op7=0/>
; CHECK-LABEL: </GLOBALVAL_SUMMARY_BLOCK
; CHECK-LABEL: <STRTAB_BLOCK
; CHECK: blob data = '_ZTS1A'
; 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.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: 7, funcFlags: (readNone: 0, readOnly: 0, noRecurse: 1, returnDoesNotAlias: 0, noInline: 0, alwaysInline: 0, noUnwind: 1, mayThrow: 0, hasUnknownCall: 0, mustBeUnreachable: 0), typeIdInfo: (typeTests: (^2)))))
; CHECK-DIS: ^2 = typeid: (name: "_ZTS1A", summary: (typeTestRes: (kind: single, sizeM1BitWidth: 0))) ; guid = 7004155349499253778
; RUN: %clang_cc1 -triple x86_64-grtev4-linux-gnu \
; RUN: -emit-obj -fthinlto-index=%t.o.thinlto.bc \
; RUN: -emit-llvm -o - -x ir %t.o | FileCheck %s --check-prefixes=CHECK-IR
; Ensure 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 \
; 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.B = type { %struct.A }
%struct.A = type { i32 (...)** }
@_ZTV1B = constant { [3 x i8*] } { [3 x i8*] [i8* undef, i8* undef, i8* undef] }, !type !0
; CHECK-IR-LABEL: define void @test
define void @test(i8* %b) {
entry:
; Ensure that traps are conditional. Invalid TYPE_ID can cause
; unconditional traps.
; CHECK-IR: br i1 {{.*}}, label %trap
%0 = bitcast i8* %b to i8**
%vtable2 = load i8*, i8** %0
%1 = tail call i1 @llvm.type.test(i8* %vtable2, metadata !"_ZTS1A")
br i1 %1, label %cont, label %trap
trap:
tail call void @llvm.trap()
unreachable
cont:
; CHECK-IR-LABEL: ret void
ret void
}
; CHECK-IR-LABEL: }
declare i1 @llvm.type.test(i8*, metadata)
declare void @llvm.trap()
declare i32 @_ZN1B1fEi(%struct.B* %this, i32 %a)
!0 = !{i64 16, !"_ZTS1A"}
!1 = !{i64 16, !"_ZTS1B"}