llvm-project/llvm/test/ThinLTO/X86/devirt_check.ll
Matthias Braun 850d53a197 LTO: Decide upfront whether to use opaque/non-opaque pointer types
LTO code may end up mixing bitcode files from various sources varying in
their use of opaque pointer types. The current strategy to decide
between opaque / typed pointers upon the first bitcode file loaded does
not work here, since we could be loading a non-opaque bitcode file first
and would then be unable to load any files with opaque pointer types
later.

So for LTO this:
- Adds an `lto::Config::OpaquePointer` option and enforces an upfront
  decision between the two modes.
- Adds `-opaque-pointers`/`-no-opaque-pointers` options to the gold
  plugin; disabled by default.
- `--opaque-pointers`/`--no-opaque-pointers` options with
  `-plugin-opt=-opaque-pointers`/`-plugin-opt=-no-opaque-pointers`
  aliases to lld; disabled by default.
- Adds an `-lto-opaque-pointers` option to the `llvm-lto2` tool.
- Changes the clang driver to pass `-plugin-opt=-opaque-pointers` to
  the linker in LTO modes when clang was configured with opaque
  pointers enabled by default.

This fixes https://github.com/llvm/llvm-project/issues/55377

Differential Revision: https://reviews.llvm.org/D125847
2022-06-01 18:05:53 -07:00

113 lines
4.1 KiB
LLVM

; REQUIRES: x86-registered-target
; Test that devirtualization option -wholeprogramdevirt-check adds code to check
; that the devirtualization decision was correct and trap or fallback if not.
; The vtables have vcall_visibility metadata with hidden visibility, to enable
; devirtualization.
; Generate unsplit module with summary for ThinLTO index-based WPD.
; RUN: opt -thinlto-bc -o %t2.o %s
; Check first in trapping mode.
; RUN: llvm-lto2 run %t2.o -save-temps -pass-remarks=. \
; RUN: -wholeprogramdevirt-check=trap \
; 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,_ZTV1B,px 2>&1 | FileCheck %s --check-prefix=REMARK
; RUN: llvm-dis %t3.1.4.opt.bc -o - | FileCheck %s --check-prefix=CHECK --check-prefix=TRAP
; Check next in fallback mode.
; RUN: llvm-lto2 run %t2.o -save-temps -pass-remarks=. \
; RUN: -wholeprogramdevirt-check=fallback \
; 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,_ZTV1B,px 2>&1 | FileCheck %s --check-prefix=REMARK
; RUN: llvm-dis %t3.1.4.opt.bc -o - | FileCheck %s --check-prefix=CHECK --check-prefix=FALLBACK
; REMARK-DAG: single-impl: 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 }
@_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, !vcall_visibility !5
; CHECK-LABEL: define i32 @test
define i32 @test(%struct.A* %obj, 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, but preceeded by a check guarding
; a trap if the function pointer doesn't match.
; TRAP: %.not = icmp eq ptr %fptr1, @_ZN1A1nEi
; Ensure !prof and !callees metadata for indirect call promotion removed.
; TRAP-NOT: prof
; TRAP-NOT: callees
; TRAP: br i1 %.not, label %1, label %0
; TRAP: 0:
; TRAP: tail call void @llvm.debugtrap()
; TRAP: br label %1
; TRAP: 1:
; TRAP: tail call i32 @_ZN1A1nEi
; Check that the call was devirtualized, but preceeded by a check guarding
; a fallback if the function pointer doesn't match.
; FALLBACK: %0 = icmp eq ptr %fptr1, @_ZN1A1nEi
; FALLBACK: br i1 %0, label %if.true.direct_targ, label %if.false.orig_indirect
; FALLBACK: if.true.direct_targ:
; FALLBACK: tail call i32 @_ZN1A1nEi
; Ensure !prof and !callees metadata for indirect call promotion removed.
; FALLBACK-NOT: prof
; FALLBACK-NOT: callees
; FALLBACK: br label %if.end.icp
; FALLBACK: if.false.orig_indirect:
; FALLBACK: tail call i32 %fptr1
; Ensure !prof and !callees metadata for indirect call promotion removed.
; In particular, if left on the fallback indirect call ICP may perform an
; additional round of promotion.
; FALLBACK-NOT: prof
; FALLBACK-NOT: callees
; FALLBACK: br label %if.end.icp
%call = tail call i32 %fptr1(%struct.A* nonnull %obj, i32 %a), !prof !6, !callees !7
ret i32 %call
}
; CHECK-LABEL: ret i32
; CHECK-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;
}
; 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"}
!3 = !{i64 16, !4}
!4 = distinct !{}
!5 = !{i64 1}
!6 = !{!"VP", i32 0, i64 1, i64 1621563287929432257, i64 1}
!7 = !{i32 (%struct.A*, i32)* @_ZN1A1nEi}