DebugInfo: Generalize the .debug_addr minimization flag to pave the way for including other strategies

3 files changed, 29 insertions, 16 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 12b6283..4626827 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -151,13 +151,18 @@ static cl::opt<LinkageNameOption>
                                             "Abstract subprograms")),
                       cl::init(DefaultLinkageNames));
 
-static cl::opt<DefaultOnOff> AlwaysUseRangesInV5(
-    "always-use-ranges-in-v5", cl::Hidden,
+static cl::opt<DwarfDebug::MinimizeAddrInV5> MinimizeAddrInV5Option(
+    "minimize-addr-in-v5", cl::Hidden,
     cl::desc("Always use DW_AT_ranges in DWARFv5 whenever it could allow more "
              "address pool entry sharing to reduce relocations/object size"),
-    cl::values(clEnumVal(Default, "Default for platform"),
-               clEnumVal(Enable, "Enabled"), clEnumVal(Disable, "Disabled")),
-    cl::init(Default));
+    cl::values(clEnumValN(DwarfDebug::MinimizeAddrInV5::Default, "Default",
+                          "Default address minimization strategy"),
+               clEnumValN(DwarfDebug::MinimizeAddrInV5::Ranges, "Ranges",
+                          "Use rnglists for contiguous ranges if that allows "
+                          "using a pre-existing base address"),
+               clEnumValN(DwarfDebug::MinimizeAddrInV5::Disabled, "Disabled",
+                          "Stuff")),
+    cl::init(DwarfDebug::MinimizeAddrInV5::Default));
 
 static constexpr unsigned ULEB128PadSize = 4;
 
@@ -433,14 +438,12 @@ DwarfDebug::DwarfDebug(AsmPrinter *A)
   // Split DWARF would benefit object size significantly by trading reductions
   // in address pool usage for slightly increased range list encodings.
   if (DwarfVersion >= 5) {
-    if (AlwaysUseRangesInV5 == Default) {
-      // FIXME: In the future, enable this by default for Split DWARF where the
-      // tradeoff is more pronounced due to being able to offload the range
-      // lists to the dwo file and shrink object files/reduce relocations there.
-      AlwaysUseRanges = false;
-    } else {
-      AlwaysUseRanges = AlwaysUseRangesInV5 == Enable;
-    }
+    MinimizeAddr = MinimizeAddrInV5Option;
+    // FIXME: In the future, enable this by default for Split DWARF where the
+    // tradeoff is more pronounced due to being able to offload the range
+    // lists to the dwo file and shrink object files/reduce relocations there.
+    if (MinimizeAddr == MinimizeAddrInV5::Default)
+      MinimizeAddr = MinimizeAddrInV5::Disabled;
   }
 
   Asm->OutStreamer->getContext().setDwarfVersion(DwarfVersion);
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
index b3b8e62..df19ef4 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -378,8 +378,16 @@ class DwarfDebug : public DebugHandlerBase {
   /// Avoid using DW_OP_convert due to consumer incompatibilities.
   bool EnableOpConvert;
 
+public:
+  enum class MinimizeAddrInV5 {
+    Default,
+    Disabled,
+    Ranges,
+  };
+
+private:
   /// Force the use of DW_AT_ranges even for single-entry range lists.
-  bool AlwaysUseRanges = false;
+  MinimizeAddrInV5 MinimizeAddr = MinimizeAddrInV5::Disabled;
 
   /// DWARF5 Experimental Options
   /// @{
@@ -694,7 +702,9 @@ public:
 
   /// Returns whether range encodings should be used for single entry range
   /// lists.
-  bool alwaysUseRanges() const { return AlwaysUseRanges; }
+  bool alwaysUseRanges() const {
+    return MinimizeAddr == MinimizeAddrInV5::Ranges;
+  }
 
   /// Returns whether to use sections as labels rather than temp symbols.
   bool useSectionsAsReferences() const {
diff --git a/llvm/test/DebugInfo/X86/ranges_always.ll b/llvm/test/DebugInfo/X86/ranges_always.ll
index c361aea..230db20 100644
--- a/llvm/test/DebugInfo/X86/ranges_always.ll
+++ b/llvm/test/DebugInfo/X86/ranges_always.ll
@@ -1,4 +1,4 @@
-; RUN: llc -O0 %s -mtriple=x86_64-unknown-linux-gnu -filetype=obj -o - -always-use-ranges-in-v5=Enable \
+; RUN: llc -O0 %s -mtriple=x86_64-unknown-linux-gnu -filetype=obj -o - -minimize-addr-in-v5=Ranges \
 ; RUN:   | llvm-dwarfdump -debug-info -debug-addr -debug-rnglists -v - \
 ; RUN:   | FileCheck --implicit-check-not=DW_TAG --implicit-check-not=NULL --implicit-check-not=DW_AT_low_pc --implicit-check-not=DW_AT_high_pc --implicit-check-not=DW_AT_ranges %s