[DEBUGINFO] Add support for emission of the inlined strings.

Summary:
Patch adds an option for emission of inlined strings rather than
.debug_str section.

Reviewers: echristo, jlebar

Subscribers: eraman, llvm-commits, JDevlieghere

Differential Revision: https://reviews.llvm.org/D43390

llvm-svn: 325583

3 files changed, 21 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 3681254ae08..dfb36fa1d43 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -115,6 +115,14 @@ DwarfAccelTables("dwarf-accel-tables", cl::Hidden,
                             clEnumVal(Disable, "Disabled")),
                  cl::init(Default));
 
+static cl::opt<DefaultOnOff>
+DwarfInlinedStrings("dwarf-inlined-strings", cl::Hidden,
+                 cl::desc("Use inlined strings rather than string section."),
+                 cl::values(clEnumVal(Default, "Default for platform"),
+                            clEnumVal(Enable, "Enabled"),
+                            clEnumVal(Disable, "Disabled")),
+                 cl::init(Default));
+
 enum LinkageNameOption {
   DefaultLinkageNames,
   AllLinkageNames,
@@ -284,6 +292,7 @@ DwarfDebug::DwarfDebug(AsmPrinter *A, Module *M)
   else
     HasDwarfAccelTables = DwarfAccelTables == Enable;
 
+  UseInlineStrings = DwarfInlinedStrings == Enable;
   HasAppleExtensionAttributes = tuneForLLDB();
 
   // Handle split DWARF.
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
index 380c868076b..f858c96d0d2 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -255,6 +255,9 @@ class DwarfDebug : public DebugHandlerBase {
   /// Whether to emit all linkage names, or just abstract subprograms.
   bool UseAllLinkageNames;
 
+  /// Use inlined strings.
+  bool UseInlineStrings = false;
+
   /// DWARF5 Experimental Options
   /// @{
   bool HasDwarfAccelTables;
@@ -491,6 +494,9 @@ public:
   /// DWARF4 format.
   bool useDWARF2Bitfields() const { return UseDWARF2Bitfields; }
 
+  /// Returns whether to use inline strings.
+  bool useInlineStrings() const { return UseInlineStrings; }
+
   // Experimental DWARF5 features.
 
   /// Returns whether or not to emit tables that dwarf consumers can
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
index 76e1228cafc..d7d5298d673 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
@@ -241,6 +241,12 @@ void DwarfUnit::addSInt(DIELoc &Die, Optional<dwarf::Form> Form,
 
 void DwarfUnit::addString(DIE &Die, dwarf::Attribute Attribute,
                           StringRef String) {
+  if (DD->useInlineStrings()) {
+    Die.addValue(DIEValueAllocator, Attribute, dwarf::DW_FORM_string,
+                 new (DIEValueAllocator)
+                     DIEInlineString(String, DIEValueAllocator));
+    return;
+  }
   auto StringPoolEntry = DU->getStringPool().getEntry(*Asm, String);
   dwarf::Form IxForm =
       isDwoUnit() ? dwarf::DW_FORM_GNU_str_index : dwarf::DW_FORM_strp;