[PATCH] D90929: [MergeFunctions] fix function attribute comparison in FunctionComparator

[Erik Eckstein via Phabricator via llvm-commits]

eeckstein created this revision.
eeckstein added a reviewer: t.p.northover.
Herald added subscribers: llvm-commits, hiraditya.
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eeckstein requested review of this revision.

The comparison of AttributeSets stopped after seeing a matching type attribute.
Subsequent mismatching attributes were not detected.

This caused a crash in the swift compiler in case one of the AttributeSet contained a swifterror attribute (after the matching type attribute).

rdar://problem/70573980


https://reviews.llvm.org/D90929

Files:
  llvm/lib/Transforms/Utils/FunctionComparator.cpp
  llvm/test/Transforms/MergeFunc/mismatching-attr-crash.ll


Index: llvm/test/Transforms/MergeFunc/mismatching-attr-crash.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/MergeFunc/mismatching-attr-crash.ll
@@ -0,0 +1,21 @@
+; RUN: opt -S -mergefunc %s | FileCheck %s
+
+; CHECK-LABEL: define void @foo
+; CHECK: call void %bc
+define void @foo(i8* byval %a0, i8* swiftself %a4) {
+entry:
+  %bc = bitcast i8* %a0 to void (i8*, i8*)*
+  call void %bc(i8* byval %a0, i8* swiftself %a4)
+  ret void
+}
+
+; CHECK-LABEL: define void @bar
+; CHECK: call void %bc
+define void @bar(i8* byval(i8) %a0, i8** swifterror %a4) {
+entry:
+  %bc = bitcast i8* %a0 to void (i8*, i8**)*
+  call void %bc(i8* byval(i8) %a0, i8** swifterror %a4)
+  ret void
+}
+
+
Index: llvm/lib/Transforms/Utils/FunctionComparator.cpp
===================================================================
--- llvm/lib/Transforms/Utils/FunctionComparator.cpp
+++ llvm/lib/Transforms/Utils/FunctionComparator.cpp
@@ -124,12 +124,17 @@
 
         Type *TyL = LA.getValueAsType();
         Type *TyR = RA.getValueAsType();
-        if (TyL && TyR)
-          return cmpTypes(TyL, TyR);
+        if (TyL && TyR) {
+          if (int Res = cmpTypes(TyL, TyR))
+            return Res;
+          continue;
+        }
 
         // Two pointers, at least one null, so the comparison result is
         // independent of the value of a real pointer.
-        return cmpNumbers((uint64_t)TyL, (uint64_t)TyR);
+        if (int Res = cmpNumbers((uint64_t)TyL, (uint64_t)TyR))
+          return Res;
+        continue;
       }
       if (LA < RA)
         return -1;


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