[PATCH] D16585: In split module utility we should never separate alias with its aliasee.

[Sergei Larin via llvm-commits]

slarin created this revision.
slarin added a subscriber: llvm-commits.

When splitting module with preserving locals, we currently do not handle case of global alias being separated with its aliasee.

http://reviews.llvm.org/D16585

Files:
  lib/Transforms/Utils/SplitModule.cpp
  test/tools/llvm-split/scc-global-alias.ll

Index: test/tools/llvm-split/scc-global-alias.ll
===================================================================
--- /dev/null
+++ test/tools/llvm-split/scc-global-alias.ll
@@ -0,0 +1,47 @@
+; We should never separate alias from aliasee.
+; RUN: llvm-split -j=3 -preserve-locals -o %t %s
+; RUN: llvm-dis -o - %t0 | FileCheck --check-prefix=CHECK0 %s
+; RUN: llvm-dis -o - %t1 | FileCheck --check-prefix=CHECK1 %s
+; RUN: llvm-dis -o - %t2 | FileCheck --check-prefix=CHECK2 %s
+
+; Checks are not critical here - verifier will assert if we fail.
+; CHECK0: @funInternal2Alias = alias
+; CHECK0: @funExternal2Alias = alias
+; CHECK0: define internal i32 @funInternal2
+; CHECK0: define i32 @funExternal2
+
+; CHECK1: @funInternalAlias = alias
+; CHECK1: define internal i32 @funInternal
+
+; CHECK2: @funExternalAlias = alias
+; CHECK2: define i32 @funExternal
+
+ at funInternalAlias = alias i32 (), i32 ()* @funInternal
+ at funExternalAlias = alias i32 (), i32 ()* @funExternal
+ at funInternal2Alias = alias i32 (), i32 ()* @funInternal2
+ at funExternal2Alias = alias i32 (), i32 ()* @funExternal2
+
+define internal i32 @funInternal() {
+entry:
+  ret i32 0
+}
+
+define i32 @funExternal() {
+entry:
+  %x = call i32 @funInternalAlias()
+  ret i32 %x
+}
+
+define internal i32 @funInternal2() {
+entry:
+  %x = call i32 @funInternalAlias()
+  ret i32 %x
+}
+
+define i32 @funExternal2() {
+entry:
+  %x = call i32 @funInternal2()
+  %y = call i32 @funExternalAlias()
+  %z = add nsw i32 %x, %y
+  ret i32 %z
+}
Index: lib/Transforms/Utils/SplitModule.cpp
===================================================================
--- lib/Transforms/Utils/SplitModule.cpp
+++ lib/Transforms/Utils/SplitModule.cpp
@@ -88,6 +88,13 @@
         Member = &GV;
     }
 
+    // For aliases we should not separate them from their aliasees regardless
+    // of linkage.
+    if (GlobalAlias *GA = dyn_cast<GlobalAlias>(&GV)) {
+      if (const Constant *C = GA->getAliasee())
+        GVtoClusterMap.unionSets(&GV, cast<GlobalValue>(C));
+    }
+
     // Further only iterate over local GVs.
     if (!GV.hasLocalLinkage())
       return;


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