Invoke add-discriminator at -g0 -fsample-profile

Summary: -fsample-profile needs discriminator, which will not be added if built with -g0. This patch makes sure the discriminator is added for sample-profile at -g0. A followup patch will be send out to update clang tests.

Reviewers: davidxl, dblaikie, echristo, dnovillo

Subscribers: mehdi_amini, probinson, llvm-commits

Differential Revision: https://reviews.llvm.org/D25132

llvm-svn: 283565

4 files changed, 6 insertions, 7 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
index f9030d118e5..025e69354d1 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -419,7 +419,7 @@ DIE *DwarfCompileUnit::constructInlinedScopeDIE(LexicalScope *Scope) {
   addUInt(*ScopeDIE, dwarf::DW_AT_call_file, None,
           getOrCreateSourceID(IA->getFilename(), IA->getDirectory()));
   addUInt(*ScopeDIE, dwarf::DW_AT_call_line, None, IA->getLine());
-  if (IA->getDiscriminator())
+  if (IA->getDiscriminator() && DD->getDwarfVersion() >= 4)
     addUInt(*ScopeDIE, dwarf::DW_AT_GNU_discriminator, None,
             IA->getDiscriminator());
 
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index d25d92e44af..aa8535c3cfc 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -1190,7 +1190,8 @@ void DwarfDebug::recordSourceLine(unsigned Line, unsigned Col, const MDNode *S,
     Fn = Scope->getFilename();
     Dir = Scope->getDirectory();
     if (auto *LBF = dyn_cast<DILexicalBlockFile>(Scope))
-      Discriminator = LBF->getDiscriminator();
+      if (DwarfVersion >= 4)
+        Discriminator = LBF->getDiscriminator();
 
     unsigned CUID = Asm->OutStreamer->getContext().getDwarfCompileUnitID();
     Src = static_cast<DwarfCompileUnit &>(*InfoHolder.getUnits()[CUID])
diff --git a/llvm/lib/MC/MCDwarf.cpp b/llvm/lib/MC/MCDwarf.cpp
index 54b2c918c84..ed27eae87ff 100644
--- a/llvm/lib/MC/MCDwarf.cpp
+++ b/llvm/lib/MC/MCDwarf.cpp
@@ -122,7 +122,8 @@ EmitDwarfLineTable(MCObjectStreamer *MCOS, MCSection *Section,
       MCOS->EmitIntValue(dwarf::DW_LNS_set_column, 1);
       MCOS->EmitULEB128IntValue(Column);
     }
-    if (Discriminator != LineEntry.getDiscriminator()) {
+    if (Discriminator != LineEntry.getDiscriminator() &&
+        MCOS->getContext().getDwarfVersion() >= 4) {
       Discriminator = LineEntry.getDiscriminator();
       unsigned Size = getULEB128Size(Discriminator);
       MCOS->EmitIntValue(dwarf::DW_LNS_extended_op, 1);
diff --git a/llvm/lib/Transforms/Utils/AddDiscriminators.cpp b/llvm/lib/Transforms/Utils/AddDiscriminators.cpp
index ee409220b46..45b4fab07ed 100644
--- a/llvm/lib/Transforms/Utils/AddDiscriminators.cpp
+++ b/llvm/lib/Transforms/Utils/AddDiscriminators.cpp
@@ -159,10 +159,7 @@ static bool addDiscriminators(Function &F) {
   // If the function has debug information, but the user has disabled
   // discriminators, do nothing.
   // Simlarly, if the function has no debug info, do nothing.
-  // Finally, if this module is built with dwarf versions earlier than 4,
-  // do nothing (discriminator support is a DWARF 4 feature).
-  if (NoDiscriminators || !F.getSubprogram() ||
-      F.getParent()->getDwarfVersion() < 4)
+  if (NoDiscriminators || !F.getSubprogram())
     return false;
 
   bool Changed = false;