[DEBUGINFO] Disable emission of the dwarf sections, but allow directives.

Summary:
Added an option that allows to emit only '.loc' and '.file' kind debug
directives, but disables emission of the DWARF sections. Required for
NVPTX target to support profiling. It requires '.loc' and '.file'
directives, but does not require any DWARF sections for the profiler.

Reviewers: probinson, echristo, dblaikie

Subscribers: aprantl, JDevlieghere, llvm-commits

Differential Revision: https://reviews.llvm.org/D46021

llvm-svn: 338616

1 files changed, 23 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 500e7a00196..549bf74a129 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -768,6 +768,8 @@ void DwarfDebug::finalizeModuleInfo() {
   // all other generation.
   for (const auto &P : CUMap) {
     auto &TheCU = *P.second;
+    if (TheCU.getCUNode()->isDebugDirectivesOnly())
+      continue;
     // Emit DW_AT_containing_type attribute to connect types with their
     // vtable holding type.
     TheCU.constructContainingTypeDIEs();
@@ -1416,6 +1418,11 @@ void DwarfDebug::endFunctionImpl(const MachineFunction *MF) {
   LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
   assert(!FnScope || SP == FnScope->getScopeNode());
   DwarfCompileUnit &TheCU = *CUMap.lookup(SP->getUnit());
+  if (TheCU.getCUNode()->isDebugDirectivesOnly()) {
+    PrevLabel = nullptr;
+    CurFn = nullptr;
+    return;
+  }
 
   DenseSet<InlinedVariable> ProcessedVars;
   collectVariableInfo(TheCU, SP, ProcessedVars);
@@ -2132,6 +2139,13 @@ void DwarfDebug::emitDebugRanges() {
         });
   };
 
+  if (llvm::all_of(CUMap, [](const decltype(CUMap)::value_type &Pair) {
+        return Pair.second->getCUNode()->isDebugDirectivesOnly();
+      })) {
+    assert(NoRangesPresent() && "No debug ranges expected.");
+    return;
+  }
+
   if (!useRangesSection()) {
     assert(NoRangesPresent() && "No debug ranges expected.");
     return;
@@ -2154,6 +2168,8 @@ void DwarfDebug::emitDebugRanges() {
   // Grab the specific ranges for the compile units in the module.
   for (const auto &I : CUMap) {
     DwarfCompileUnit *TheCU = I.second;
+    if (TheCU->getCUNode()->isDebugDirectivesOnly())
+      continue;
 
     if (auto *Skel = TheCU->getSkeleton())
       TheCU = Skel;
@@ -2206,12 +2222,19 @@ void DwarfDebug::emitDebugMacinfo() {
   if (CUMap.empty())
     return;
 
+  if (llvm::all_of(CUMap, [](const decltype(CUMap)::value_type &Pair) {
+        return Pair.second->getCUNode()->isDebugDirectivesOnly();
+      }))
+    return;
+
   // Start the dwarf macinfo section.
   Asm->OutStreamer->SwitchSection(
       Asm->getObjFileLowering().getDwarfMacinfoSection());
 
   for (const auto &P : CUMap) {
     auto &TheCU = *P.second;
+    if (TheCU.getCUNode()->isDebugDirectivesOnly())
+      continue;
     auto *SkCU = TheCU.getSkeleton();
     DwarfCompileUnit &U = SkCU ? *SkCU : TheCU;
     auto *CUNode = cast<DICompileUnit>(P.first);