[CodeView] Add option to disable inline line tables.

Summary:
This adds a clang option to disable inline line tables. When it is used,
the inliner uses the call site as the location of the inlined function instead of
marking it as an inline location with the function location.

See https://bugs.llvm.org/show_bug.cgi?id=42344

Reviewers: rnk

Subscribers: hiraditya, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D67723

1 files changed, 30 insertions, 11 deletions

diff --git a/llvm/lib/Transforms/Utils/InlineFunction.cpp b/llvm/lib/Transforms/Utils/InlineFunction.cpp
index 7e08da35563..b522dd2b631 100644
--- a/llvm/lib/Transforms/Utils/InlineFunction.cpp
+++ b/llvm/lib/Transforms/Utils/InlineFunction.cpp
@@ -1405,6 +1405,10 @@ static void fixupLineNumbers(Function *Fn, Function::iterator FI,
   // other.
   DenseMap<const MDNode *, MDNode *> IANodes;
 
+  // Check if we are not generating inline line tables and want to use
+  // the call site location instead.
+  bool NoInlineLineTables = Fn->hasFnAttribute("no-inline-line-tables");
+
   for (; FI != Fn->end(); ++FI) {
     for (BasicBlock::iterator BI = FI->begin(), BE = FI->end();
          BI != BE; ++BI) {
@@ -1416,20 +1420,22 @@ static void fixupLineNumbers(Function *Fn, Function::iterator FI,
         BI->setMetadata(LLVMContext::MD_loop, NewLoopID);
       }
 
-      if (DebugLoc DL = BI->getDebugLoc()) {
-        DebugLoc IDL =
-            inlineDebugLoc(DL, InlinedAtNode, BI->getContext(), IANodes);
-        BI->setDebugLoc(IDL);
-        continue;
-      }
+      if (!NoInlineLineTables)
+        if (DebugLoc DL = BI->getDebugLoc()) {
+          DebugLoc IDL =
+              inlineDebugLoc(DL, InlinedAtNode, BI->getContext(), IANodes);
+          BI->setDebugLoc(IDL);
+          continue;
+        }
 
-      if (CalleeHasDebugInfo)
+      if (CalleeHasDebugInfo && !NoInlineLineTables)
         continue;
 
-      // If the inlined instruction has no line number, make it look as if it
-      // originates from the call location. This is important for
-      // ((__always_inline__, __nodebug__)) functions which must use caller
-      // location for all instructions in their function body.
+      // If the inlined instruction has no line number, or if inline info
+      // is not being generated, make it look as if it originates from the call
+      // location. This is important for ((__always_inline, __nodebug__))
+      // functions which must use caller location for all instructions in their
+      // function body.
 
       // Don't update static allocas, as they may get moved later.
       if (auto *AI = dyn_cast<AllocaInst>(BI))
@@ -1438,6 +1444,19 @@ static void fixupLineNumbers(Function *Fn, Function::iterator FI,
 
       BI->setDebugLoc(TheCallDL);
     }
+
+    // Remove debug info intrinsics if we're not keeping inline info.
+    if (NoInlineLineTables) {
+      BasicBlock::iterator BI = FI->begin();
+      while (BI != FI->end()) {
+        if (isa<DbgInfoIntrinsic>(BI)) {
+          BI = BI->eraseFromParent();
+          continue;
+        }
+        ++BI;
+      }
+    }
+
   }
 }