f10e0f7321
Avoid creating new calls to linkonce_odr/weak_odr functions when
merging 2 functions, as this may introduce an infinite call
cycle.
Consider 2 functions below, both present in 2 modules.
Module X
--
define linkonce_odr void @"A"() {
call void @"foo"()
}
define linkonce_odr void @"B"() {
call void @"foo"()
}
---
Module Y
---
global @"g" = @"B"
define linkonce_odr void @"A"() {
%l = load @"g"
call void %l()
}
define linkonce_odr void @"B"() {
call void @"foo"()
}
---
@"A" and @"B" in both modules are semantically equivalent
Module X after function merging:
---
define linkonce_odr void @"A"() {
call void @"foo"()
}
define linkonce_odr void @"B"() {
call void @"A"()
}
---
Module Y is unchanged.
Then the linker picks @"A" from module Y and @"B" from module X. Now there's an infinite call cycle
PR: https://github.com/llvm/llvm-project/pull/125050
76 lines
2.2 KiB
LLVM
76 lines
2.2 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --check-globals all --include-generated-funcs --version 5
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; RUN: opt -p mergefunc -S %s | FileCheck %s
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@llvm.used = appending global [3 x ptr] [ptr @weak_odr_caller_of_foo_1, ptr @weak_odr_caller_of_foo_2, ptr @weak_odr_caller_of_foo_3]
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define void @caller_of_callers(ptr %p) {
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call void @weak_odr_caller_of_foo_1(ptr %p)
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call void @weak_odr_caller_of_foo_2(ptr %p)
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call void @weak_odr_caller_of_foo_3(ptr %p)
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ret void
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}
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define weak_odr void @weak_odr_caller_of_foo_1(ptr %p) {
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entry:
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tail call void @foo(ptr %p)
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tail call void @foo(ptr %p)
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tail call void @foo(ptr %p)
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ret void
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}
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define weak_odr void @weak_odr_caller_of_foo_2(ptr %p) {
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entry:
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tail call void @foo(ptr %p)
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tail call void @foo(ptr %p)
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tail call void @foo(ptr %p)
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ret void
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}
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define weak_odr void @weak_odr_caller_of_foo_3(ptr %p) {
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entry:
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tail call void @foo(ptr %p)
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tail call void @foo(ptr %p)
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tail call void @foo(ptr %p)
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ret void
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}
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declare void @foo(ptr)
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;.
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; CHECK: @llvm.used = appending global [3 x ptr] [ptr @weak_odr_caller_of_foo_1, ptr @weak_odr_caller_of_foo_2, ptr @weak_odr_caller_of_foo_3]
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;.
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; CHECK-LABEL: define void @caller_of_callers(
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; CHECK-SAME: ptr [[P:%.*]]) {
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; CHECK-NEXT: call void @[[GLOB0:[0-9]+]](ptr [[P]])
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; CHECK-NEXT: call void @[[GLOB0]](ptr [[P]])
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; CHECK-NEXT: call void @[[GLOB0]](ptr [[P]])
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; CHECK-NEXT: ret void
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;
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;
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; CHECK-LABEL: define private void @0(
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; CHECK-SAME: ptr [[P:%.*]]) {
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; CHECK-NEXT: [[ENTRY:.*:]]
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; CHECK-NEXT: tail call void @foo(ptr [[P]])
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; CHECK-NEXT: tail call void @foo(ptr [[P]])
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; CHECK-NEXT: tail call void @foo(ptr [[P]])
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; CHECK-NEXT: ret void
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;
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;
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; CHECK-LABEL: define weak_odr void @weak_odr_caller_of_foo_2(
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; CHECK-SAME: ptr [[TMP0:%.*]]) {
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; CHECK-NEXT: tail call void @[[GLOB0]](ptr [[TMP0]])
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; CHECK-NEXT: ret void
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;
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;
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; CHECK-LABEL: define weak_odr void @weak_odr_caller_of_foo_1(
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; CHECK-SAME: ptr [[TMP0:%.*]]) {
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; CHECK-NEXT: tail call void @[[GLOB0]](ptr [[TMP0]])
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; CHECK-NEXT: ret void
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;
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;
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; CHECK-LABEL: define weak_odr void @weak_odr_caller_of_foo_3(
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; CHECK-SAME: ptr [[TMP0:%.*]]) {
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; CHECK-NEXT: tail call void @[[GLOB0]](ptr [[TMP0]])
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; CHECK-NEXT: ret void
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;
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