Revert "Revert "DI: Fold constant arguments into a single MDString""

This reverts commit r218918, effectively reapplying r218914 after fixing
an Ocaml bindings test and an Asan crash.  The root cause of the latter
was a tightened-up check in `DILexicalBlock::Verify()`, so I'll file a
PR to investigate who requires the loose check (and why).

Original commit message follows.

--

This patch addresses the first stage of PR17891 by folding constant
arguments together into a single MDString.  Integers are stringified and
a `\0` character is used as a separator.

Part of PR17891.

Note: I've attached my testcases upgrade scripts to the PR.  If I've
just broken your out-of-tree testcases, they might help.

llvm-svn: 219010

1 files changed, 2 insertions, 8 deletions

diff --git a/llvm/lib/IR/DebugLoc.cpp b/llvm/lib/IR/DebugLoc.cpp
index e8bdccebae9..718da852fec 100644
--- a/llvm/lib/IR/DebugLoc.cpp
+++ b/llvm/lib/IR/DebugLoc.cpp
@@ -79,14 +79,8 @@ MDNode *DebugLoc::getScopeNode(const LLVMContext &Ctx) const {
 DebugLoc DebugLoc::getFnDebugLoc(const LLVMContext &Ctx) const {
   const MDNode *Scope = getScopeNode(Ctx);
   DISubprogram SP = getDISubprogram(Scope);
-  if (SP.isSubprogram()) {
-    // Check for number of operands since the compatibility is
-    // cheap here.  FIXME: Name the magic constant.
-    if (SP->getNumOperands() > 19)
-      return DebugLoc::get(SP.getScopeLineNumber(), 0, SP);
-    else
-      return DebugLoc::get(SP.getLineNumber(), 0, SP);
-  }
+  if (SP.isSubprogram())
+    return DebugLoc::get(SP.getScopeLineNumber(), 0, SP);
 
   return DebugLoc();
 }