Refactor DebugLocDWARFExpression so it doesn't require access to the

TargetRegisterInfo. DebugLocEntry now holds a buffer with the raw bytes
of the pre-calculated DWARF expression.

Ought to be NFC, but it does slightly alter the output format of the
textual assembly.

This reapplies 230930 without the assertion in DebugLocEntry::finalize()
because not all Machine registers can be lowered into DWARF register
numbers and floating point constants cannot be expressed.

llvm-svn: 231023

1 files changed, 25 insertions, 12 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DebugLocEntry.h b/llvm/lib/CodeGen/AsmPrinter/DebugLocEntry.h
index 6d55c038541..6f30d294f71 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DebugLocEntry.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DebugLocEntry.h
@@ -9,22 +9,24 @@
 
 #ifndef LLVM_LIB_CODEGEN_ASMPRINTER_DEBUGLOCENTRY_H
 #define LLVM_LIB_CODEGEN_ASMPRINTER_DEBUGLOCENTRY_H
+#include "llvm/ADT/SmallString.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/DebugInfo.h"
 #include "llvm/MC/MCSymbol.h"
 #include "llvm/MC/MachineLocation.h"
 
 namespace llvm {
+class AsmPrinter;
 class MDNode;
 /// \brief This struct describes location entries emitted in the .debug_loc
 /// section.
 class DebugLocEntry {
-  // Begin and end symbols for the address range that this location is valid.
+  /// Begin and end symbols for the address range that this location is valid.
   const MCSymbol *Begin;
   const MCSymbol *End;
 
 public:
-  /// A single location or constant.
+  /// \brief A single location or constant.
   struct Value {
     Value(const MDNode *Var, const MDNode *Expr, int64_t i)
         : Variable(Var), Expression(Expr), EntryKind(E_Integer) {
@@ -44,17 +46,17 @@ public:
       assert(DIExpression(Expr).Verify());
     }
 
-    // The variable to which this location entry corresponds.
+    /// The variable to which this location entry corresponds.
     const MDNode *Variable;
 
-    // Any complex address location expression for this Value.
+    /// Any complex address location expression for this Value.
     const MDNode *Expression;
 
-    // Type of entry that this represents.
+    /// Type of entry that this represents.
     enum EntryType { E_Location, E_Integer, E_ConstantFP, E_ConstantInt };
     enum EntryType EntryKind;
 
-    // Either a constant,
+    /// Either a constant,
     union {
       int64_t Int;
       const ConstantFP *CFP;
@@ -84,6 +86,8 @@ private:
   /// A nonempty list of locations/constants belonging to this entry,
   /// sorted by offset.
   SmallVector<Value, 1> Values;
+  SmallString<8> DWARFBytes;
+  SmallVector<std::string, 1> Comments;
 
 public:
   DebugLocEntry(const MCSymbol *B, const MCSymbol *E, Value Val)
@@ -92,9 +96,9 @@ public:
   }
 
   /// \brief If this and Next are describing different pieces of the same
-  // variable, merge them by appending Next's values to the current
-  // list of values.
-  // Return true if the merge was successful.
+  /// variable, merge them by appending Next's values to the current
+  /// list of values.
+  /// Return true if the merge was successful.
   bool MergeValues(const DebugLocEntry &Next) {
     if (Begin == Next.Begin) {
       DIExpression Expr(Values[0].Expression);
@@ -135,7 +139,7 @@ public:
         }) && "value must be a piece");
   }
 
-  // Sort the pieces by offset.
+  // \brief Sort the pieces by offset.
   // Remove any duplicate entries by dropping all but the first.
   void sortUniqueValues() {
     std::sort(Values.begin(), Values.end());
@@ -146,9 +150,18 @@ public:
                  }),
                  Values.end());
   }
+
+  /// \brief Lower this entry into a DWARF expression.
+  void finalize(const AsmPrinter &AP,
+                const DITypeIdentifierMap &TypeIdentifierMap);
+
+  /// \brief Return the lowered DWARF expression.
+  StringRef getDWARFBytes() const { return DWARFBytes; }
+  /// \brief Return the assembler comments for the lowered DWARF expression.
+  const SmallVectorImpl<std::string> &getComments() const { return Comments; }
 };
 
-/// Compare two Values for equality.
+/// \brief Compare two Values for equality.
 inline bool operator==(const DebugLocEntry::Value &A,
                        const DebugLocEntry::Value &B) {
   if (A.EntryKind != B.EntryKind)
@@ -173,7 +186,7 @@ inline bool operator==(const DebugLocEntry::Value &A,
   llvm_unreachable("unhandled EntryKind");
 }
 
-/// Compare two pieces based on their offset.
+/// \brief Compare two pieces based on their offset.
 inline bool operator<(const DebugLocEntry::Value &A,
                       const DebugLocEntry::Value &B) {
   return A.getExpression().getBitPieceOffset() <