[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

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 3681254..dfb36fa 100644 (file)
--- 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 380c868..f858c96 100644 (file)
--- 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 76e1228..d7d5298 100644 (file)
--- 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;

diff --git a/llvm/test/DebugInfo/Generic/inlined-strings.ll b/llvm/test/DebugInfo/Generic/inlined-strings.ll
new file mode 100644 (file)
index 0000000..18c15b2
--- /dev/null
+++ b/llvm/test/DebugInfo/Generic/inlined-strings.ll
@@ -0,0 +1,45 @@
+; REQUIRES: object-emission
+
+; RUN: %llc_dwarf -O0 -filetype=obj < %s -dwarf-inlined-strings=Enable -o - | llvm-dwarfdump -show-form - | FileCheck %s
+
+; Also test that the null streamer doesn't crash with debug info.
+; RUN: %llc_dwarf -O0 -filetype=null < %s -dwarf-inlined-strings=Enable
+
+; generated from the following source compiled to bitcode with clang -g -O1
+; static int i;
+; int main() {
+;   (void)&i;
+; }
+
+; CHECK-NOT: DW_FORM_str{{(p|x)}}
+; CHECK: DW_FORM_string
+; CHECK-NOT: DW_FORM_str{{(p|x)}}
+
+
+source_filename = "test/DebugInfo/Generic/global.ll"
+
+; Function Attrs: nounwind readnone uwtable
+define i32 @main() #0 !dbg !9 {
+entry:
+  ret i32 0, !dbg !12
+}
+
+attributes #0 = { nounwind readnone uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "unsafe-fp-math"="false" "use-soft-float"="false" }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!7, !8}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 3.4 ", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !2, globals: !3, imports: !2)
+!1 = !DIFile(filename: "global.cpp", directory: "/tmp")
+!2 = !{}
+!3 = !{!4}
+!4 = !DIGlobalVariableExpression(var: !5, expr: !DIExpression())
+!5 = !DIGlobalVariable(name: "i", linkageName: "_ZL1i", scope: null, file: !1, line: 1, type: !6, isLocal: true, isDefinition: true)
+!6 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
+!7 = !{i32 2, !"Dwarf Version", i32 3}
+!8 = !{i32 1, !"Debug Info Version", i32 3}
+!9 = distinct !DISubprogram(name: "main", scope: !1, file: !1, line: 2, type: !10, isLocal: false, isDefinition: true, scopeLine: 2, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: true, unit: !0, variables: !2)
+!10 = !DISubroutineType(types: !11)
+!11 = !{!6}
+!12 = !DILocation(line: 4, scope: !9)
+