[PATCH] D33513: [ThinLTO] Fix ThinLTO crash while destroying context

[Charles Saternos via Phabricator via llvm-commits]

ncharlie updated this revision to Diff 110184.

https://reviews.llvm.org/D33513

Files:
  include/llvm/IR/Metadata.h
  test/ThinLTO/X86/lazy-load-temporaries-cleanup.ll
  tools/llvm-dis/llvm-dis.cpp


Index: tools/llvm-dis/llvm-dis.cpp
===================================================================
--- tools/llvm-dis/llvm-dis.cpp
+++ tools/llvm-dis/llvm-dis.cpp
@@ -51,8 +51,13 @@
 DontPrint("disable-output", cl::desc("Don't output the .ll file"), cl::Hidden);
 
 static cl::opt<bool>
-ShowAnnotations("show-annotations",
-                cl::desc("Add informational comments to the .ll file"));
+    SetImporting("set-importing",
+                 cl::desc("Set lazy loading to pretend to import a module"),
+                 cl::Hidden);
+
+static cl::opt<bool>
+    ShowAnnotations("show-annotations",
+                    cl::desc("Add informational comments to the .ll file"));
 
 static cl::opt<bool> PreserveAssemblyUseListOrder(
     "preserve-ll-uselistorder",
@@ -142,9 +147,9 @@
 static std::unique_ptr<Module> openInputFile(LLVMContext &Context) {
   std::unique_ptr<MemoryBuffer> MB =
       ExitOnErr(errorOrToExpected(MemoryBuffer::getFileOrSTDIN(InputFilename)));
-  std::unique_ptr<Module> M =
-      ExitOnErr(getOwningLazyBitcodeModule(std::move(MB), Context,
-                                           /*ShouldLazyLoadMetadata=*/true));
+  std::unique_ptr<Module> M = ExitOnErr(getOwningLazyBitcodeModule(
+      std::move(MB), Context,
+      /*ShouldLazyLoadMetadata=*/true, SetImporting));
   if (MaterializeMetadata)
     ExitOnErr(M->materializeMetadata());
   else
Index: test/ThinLTO/X86/lazy-load-temporaries-cleanup.ll
===================================================================
--- /dev/null
+++ test/ThinLTO/X86/lazy-load-temporaries-cleanup.ll
@@ -0,0 +1,16 @@
+; This test ensures that metadata temporaries are properly tracked, then cleaned up
+
+; RUN: opt -module-summary -bitcode-mdindex-threshold=0 %s | llvm-dis -materialize-metadata -set-importing -o - | FileCheck %s
+; CHECK: !named = !{!0}
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define void  @patatino() {
+  ret void
+}
+
+!named = !{!0}
+
+!0  =  distinct !{!1, i8 0}
+!1  = !{i8 1}
Index: include/llvm/IR/Metadata.h
===================================================================
--- include/llvm/IR/Metadata.h
+++ include/llvm/IR/Metadata.h
@@ -1303,7 +1303,12 @@
     if (!Use)
       return;
     *Use = MD;
-    Use = nullptr;
+
+    if (*Use)
+      MetadataTracking::track(*Use);
+
+    MetadataTracking::untrack(this);
+    assert(!Use && "Use is still being tracked despite being untracked!");
   }
 };
 


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