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| author | Arthur Eubanks <aeubanks@google.com> | 2022-06-30 15:18:04 -0700 |
|---|---|---|
| committer | Arthur Eubanks <aeubanks@google.com> | 2022-07-26 08:01:08 -0700 |
| commit | 2eade1dba4a8d6e1c6867e9127bcd88cf4e55976 (patch) | |
| tree | 080ccfec588a3231d14022bc922f5c05e9a11adb /lld | |
| parent | e43621b09c9741d2e3a8a3d8ed216699af5ff8ba (diff) | |
| download | llvm-2eade1dba4a8d6e1c6867e9127bcd88cf4e55976.zip llvm-2eade1dba4a8d6e1c6867e9127bcd88cf4e55976.tar.gz llvm-2eade1dba4a8d6e1c6867e9127bcd88cf4e55976.tar.bz2 | |
[WPD] Use new llvm.public.type.test intrinsic for potentially publicly visible classes
Turning on opaque pointers has uncovered an issue with WPD where we currently pattern match away `assume(type.test)` in WPD so that a later LTT doesn't resolve the type test to undef and introduce an `assume(false)`. The pattern matching can fail in cases where we transform two `assume(type.test)`s into `assume(phi(type.test.1, type.test.2))`.
Currently we create `assume(type.test)` for all virtual calls that might be devirtualized. This is to support `-Wl,--lto-whole-program-visibility`.
To prevent this, all virtual calls that may not be in the same LTO module instead use a new `llvm.public.type.test` intrinsic in place of the `llvm.type.test`. Then when we know if `-Wl,--lto-whole-program-visibility` is passed or not, we can either replace all `llvm.public.type.test` with `llvm.type.test`, or replace all `llvm.public.type.test` with `true`. This prevents WPD from trying to pattern match away `assume(type.test)` for public virtual calls when failing the pattern matching will result in miscompiles.
Reviewed By: tejohnson
Differential Revision: https://reviews.llvm.org/D128955
Diffstat (limited to 'lld')
| -rw-r--r-- | lld/test/ELF/lto/update_public_type_test.ll | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/lld/test/ELF/lto/update_public_type_test.ll b/lld/test/ELF/lto/update_public_type_test.ll new file mode 100644 index 0000000..037e7b9 --- /dev/null +++ b/lld/test/ELF/lto/update_public_type_test.ll @@ -0,0 +1,27 @@ +; REQUIRES: x86 + +; Check that we RAUW llvm.public.type.test with either llvm.type.test when --lto-whole-program-visibility is specified, or with true otherwise. + +; RUN: opt --thinlto-bc -o %t.o %s +; RUN: ld.lld %t.o -o %t2.o --save-temps +; RUN: llvm-dis %t.o.0.preopt.bc -o - | FileCheck %s --check-prefix=PUB +; RUN: ld.lld %t.o -o %t3.o --save-temps --lto-whole-program-visibility +; RUN: llvm-dis %t.o.0.preopt.bc -o - | FileCheck %s --check-prefix=WPV + +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" + +declare i1 @llvm.public.type.test(ptr, metadata) +declare void @llvm.assume(i1) + +; PUB-NOT: call {{.*}}@llvm.public.type.test +; PUB-NOT: call {{.*}}@llvm.type.test +; PUB: call {{.*}}@llvm.assume(i1 true) +; WPV: call {{.*}}@llvm.type.test +; WPV: call {{.*}}@llvm.assume + +define void @f(ptr %a) { + %i = call i1 @llvm.public.type.test(ptr %a, metadata !"_ZTS1A") + call void @llvm.assume(i1 %i) + ret void +} |