DI: Set DILexicalBlock columns >= 65536 to 0/unknown

This fixes PR24621 and matches what we do for `DILocation`.  Although
the limit seems somewhat artificial, there are places in the backend
that also assume 16-bit columns, so we may as well just be consistent
about the limits.

llvm-svn: 246349

3 files changed, 33 insertions, 2 deletions

diff --git a/llvm/include/llvm/IR/DebugInfoMetadata.h b/llvm/include/llvm/IR/DebugInfoMetadata.h
index eeacbdbf343..6fba3b59396 100644
--- a/llvm/include/llvm/IR/DebugInfoMetadata.h
+++ b/llvm/include/llvm/IR/DebugInfoMetadata.h
@@ -1430,12 +1430,14 @@ class DILexicalBlock : public DILexicalBlockBase {
   friend class MDNode;
 
   unsigned Line;
-  unsigned Column;
+  uint16_t Column;
 
   DILexicalBlock(LLVMContext &C, StorageType Storage, unsigned Line,
                  unsigned Column, ArrayRef<Metadata *> Ops)
       : DILexicalBlockBase(C, DILexicalBlockKind, Storage, Ops), Line(Line),
-        Column(Column) {}
+        Column(Column) {
+    assert(Column < (1u << 16) && "Expected 16-bit column");
+  }
   ~DILexicalBlock() = default;
 
   static DILexicalBlock *getImpl(LLVMContext &Context, DILocalScope *Scope,
diff --git a/llvm/lib/IR/DebugInfoMetadata.cpp b/llvm/lib/IR/DebugInfoMetadata.cpp
index 89111f73ae2..3c293c25c91 100644
--- a/llvm/lib/IR/DebugInfoMetadata.cpp
+++ b/llvm/lib/IR/DebugInfoMetadata.cpp
@@ -386,6 +386,9 @@ DILexicalBlock *DILexicalBlock::getImpl(LLVMContext &Context, Metadata *Scope,
                                         Metadata *File, unsigned Line,
                                         unsigned Column, StorageType Storage,
                                         bool ShouldCreate) {
+  // Fixup column.
+  adjustColumn(Column);
+
   assert(Scope && "Expected scope");
   DEFINE_GETIMPL_LOOKUP(DILexicalBlock, (Scope, File, Line, Column));
   Metadata *Ops[] = {File, Scope};
diff --git a/llvm/unittests/IR/MetadataTest.cpp b/llvm/unittests/IR/MetadataTest.cpp
index 6741c79afc9..661f965660e 100644
--- a/llvm/unittests/IR/MetadataTest.cpp
+++ b/llvm/unittests/IR/MetadataTest.cpp
@@ -1591,6 +1591,32 @@ TEST_F(DILexicalBlockTest, get) {
   EXPECT_EQ(N, MDNode::replaceWithUniqued(std::move(Temp)));
 }
 
+TEST_F(DILexicalBlockTest, Overflow) {
+  DISubprogram *SP = getSubprogram();
+  DIFile *F = getFile();
+  {
+    auto *LB = DILexicalBlock::get(Context, SP, F, 2, 7);
+    EXPECT_EQ(2u, LB->getLine());
+    EXPECT_EQ(7u, LB->getColumn());
+  }
+  unsigned U16 = 1u << 16;
+  {
+    auto *LB = DILexicalBlock::get(Context, SP, F, UINT32_MAX, U16 - 1);
+    EXPECT_EQ(UINT32_MAX, LB->getLine());
+    EXPECT_EQ(U16 - 1, LB->getColumn());
+  }
+  {
+    auto *LB = DILexicalBlock::get(Context, SP, F, UINT32_MAX, U16);
+    EXPECT_EQ(UINT32_MAX, LB->getLine());
+    EXPECT_EQ(0u, LB->getColumn());
+  }
+  {
+    auto *LB = DILexicalBlock::get(Context, SP, F, UINT32_MAX, U16 + 1);
+    EXPECT_EQ(UINT32_MAX, LB->getLine());
+    EXPECT_EQ(0u, LB->getColumn());
+  }
+}
+
 typedef MetadataTest DILexicalBlockFileTest;
 
 TEST_F(DILexicalBlockFileTest, get) {