Don't generate line&scope debug info for meta-instructions.

MachineInstructions that don't generate any code (such as
IMPLICIT_DEFs) should not generate any debug info either.

Fixes PR33107.

https://bugs.llvm.org/show_bug.cgi?id=33107

This reapplies r303566 without any modifications. The stage2 build
failures persisted even after reverting this patch, and looking back
through history, it looks like these tests are flaky.

llvm-svn: 303575

4 files changed, 10 insertions, 9 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
index 1b39e46ee46..881531078a5 100644
--- a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
@@ -1025,11 +1025,11 @@ void CodeViewDebug::beginFunctionImpl(const MachineFunction *MF) {
   bool EmptyPrologue = true;
   for (const auto &MBB : *MF) {
     for (const auto &MI : MBB) {
-      if (!MI.isDebugValue() && !MI.getFlag(MachineInstr::FrameSetup) &&
+      if (!MI.isMetaInstruction() && !MI.getFlag(MachineInstr::FrameSetup) &&
           MI.getDebugLoc()) {
         PrologEndLoc = MI.getDebugLoc();
         break;
-      } else if (!MI.isDebugValue()) {
+      } else if (!MI.isMetaInstruction()) {
         EmptyPrologue = false;
       }
     }
diff --git a/llvm/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp b/llvm/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp
index 826162ad47c..27ae77b18cd 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp
@@ -223,9 +223,9 @@ void DebugHandlerBase::endInstruction() {
     return;
 
   assert(CurMI != nullptr);
-  // Don't create a new label after DBG_VALUE instructions.
-  // They don't generate code.
-  if (!CurMI->isDebugValue()) {
+  // Don't create a new label after DBG_VALUE and other instructions that don't
+  // generate code.
+  if (!CurMI->isMetaInstruction()) {
     PrevLabel = nullptr;
     PrevInstBB = CurMI->getParent();
   }
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 3410b98d777..8fb3db274ec 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -1029,7 +1029,7 @@ void DwarfDebug::beginInstruction(const MachineInstr *MI) {
   assert(CurMI);
 
   // Check if source location changes, but ignore DBG_VALUE and CFI locations.
-  if (MI->isDebugValue() || MI->isCFIInstruction())
+  if (MI->isMetaInstruction())
     return;
   const DebugLoc &DL = MI->getDebugLoc();
   // When we emit a line-0 record, we don't update PrevInstLoc; so look at
@@ -1111,7 +1111,7 @@ static DebugLoc findPrologueEndLoc(const MachineFunction *MF) {
   // the beginning of the function body.
   for (const auto &MBB : *MF)
     for (const auto &MI : MBB)
-      if (!MI.isDebugValue() && !MI.getFlag(MachineInstr::FrameSetup) &&
+      if (!MI.isMetaInstruction() && !MI.getFlag(MachineInstr::FrameSetup) &&
           MI.getDebugLoc())
         return MI.getDebugLoc();
   return DebugLoc();
diff --git a/llvm/lib/CodeGen/LexicalScopes.cpp b/llvm/lib/CodeGen/LexicalScopes.cpp
index 275d84e2c18..40ee7ea785f 100644
--- a/llvm/lib/CodeGen/LexicalScopes.cpp
+++ b/llvm/lib/CodeGen/LexicalScopes.cpp
@@ -86,8 +86,9 @@ void LexicalScopes::extractLexicalScopes(
         continue;
       }
 
-      // Ignore DBG_VALUE. It does not contribute to any instruction in output.
-      if (MInsn.isDebugValue())
+      // Ignore DBG_VALUE and similar instruction that do not contribute to any
+      // instruction in the output.
+      if (MInsn.isMetaInstruction())
         continue;
 
       if (RangeBeginMI) {