[llvm] b629d4b - [Attributor] Prevent infinite loop in AAGlobalValueInfoFloating (#94941)
via llvm-commits
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Tue Jun 18 09:36:45 PDT 2024
Author: Ethan Luis McDonough
Date: 2024-06-18T09:36:42-07:00
New Revision: b629d4b91291328090023b5405dbbaabfd38d961
URL: https://github.com/llvm/llvm-project/commit/b629d4b91291328090023b5405dbbaabfd38d961
DIFF: https://github.com/llvm/llvm-project/commit/b629d4b91291328090023b5405dbbaabfd38d961.diff
LOG: [Attributor] Prevent infinite loop in AAGlobalValueInfoFloating (#94941)
Global variables that reference themselves alongside a function that is
called indirectly can cause an infinite loop in
`AAGlobalValueInfoFloating`. The recursive reference is continually
pushed back into the workload, causing the attributor to hang
indefinitely.
Added:
llvm/test/Transforms/Attributor/recursive_globals.ll
Modified:
llvm/lib/Transforms/IPO/Attributor.cpp
Removed:
################################################################################
diff --git a/llvm/lib/Transforms/IPO/Attributor.cpp b/llvm/lib/Transforms/IPO/Attributor.cpp
index 09d7ee7c9478d..5286228a97941 100644
--- a/llvm/lib/Transforms/IPO/Attributor.cpp
+++ b/llvm/lib/Transforms/IPO/Attributor.cpp
@@ -1749,6 +1749,10 @@ bool Attributor::checkForAllCallees(
return Pred(Callees.getArrayRef());
}
+bool canMarkAsVisited(const User *Usr) {
+ return isa<PHINode>(Usr) || !isa<Instruction>(Usr);
+}
+
bool Attributor::checkForAllUses(
function_ref<bool(const Use &, bool &)> Pred,
const AbstractAttribute &QueryingAA, const Value &V,
@@ -1796,7 +1800,7 @@ bool Attributor::checkForAllUses(
while (!Worklist.empty()) {
const Use *U = Worklist.pop_back_val();
- if (isa<PHINode>(U->getUser()) && !Visited.insert(U).second)
+ if (canMarkAsVisited(U->getUser()) && !Visited.insert(U).second)
continue;
DEBUG_WITH_TYPE(VERBOSE_DEBUG_TYPE, {
if (auto *Fn = dyn_cast<Function>(U->getUser()))
diff --git a/llvm/test/Transforms/Attributor/recursive_globals.ll b/llvm/test/Transforms/Attributor/recursive_globals.ll
new file mode 100644
index 0000000000000..b2b27b15c7eea
--- /dev/null
+++ b/llvm/test/Transforms/Attributor/recursive_globals.ll
@@ -0,0 +1,47 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -passes=attributor -S < %s | FileCheck %s
+
+; Global variables that reference themselves alongside a function that is called indirectly
+; used to cause an infinite loop in the attributor. The recursive reference was continually
+; pushed back into the workload, causing the attributor to hang indefinitely.
+
+ at glob1 = global { ptr, ptr } { ptr @glob1, ptr @fnc1 }
+ at glob2 = global { ptr, ptr } { ptr @glob3, ptr @fnc2 }
+ at glob3 = global { ptr, ptr } { ptr @glob2, ptr @fnc2 }
+
+define internal void @fnc1() {
+; CHECK-LABEL: define internal void @fnc1(
+; CHECK-SAME: ) #[[ATTR0:[0-9]+]] {
+; CHECK-NEXT: ret void
+;
+ ret void
+}
+
+define internal void @fnc2() {
+; CHECK-LABEL: define internal void @fnc2(
+; CHECK-SAME: ) #[[ATTR0]] {
+; CHECK-NEXT: ret void
+;
+ ret void
+}
+
+define dso_local void @indr_caller(ptr %0) {
+; CHECK-LABEL: define dso_local void @indr_caller(
+; CHECK-SAME: ptr nocapture nofree noundef nonnull [[TMP0:%.*]]) {
+; CHECK-NEXT: call void [[TMP0]]()
+; CHECK-NEXT: ret void
+;
+ call void %0()
+ ret void
+}
+
+define void @main() {
+; CHECK-LABEL: define void @main() {
+; CHECK-NEXT: call void @indr_caller(ptr nocapture nofree noundef nonnull @fnc1)
+; CHECK-NEXT: call void @indr_caller(ptr nocapture nofree noundef nonnull @fnc2)
+; CHECK-NEXT: ret void
+;
+ call void @indr_caller(ptr @fnc1)
+ call void @indr_caller(ptr @fnc2)
+ ret void
+}
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