DebugInfo: Use assembly label arithmetic for address pool size for easier reading/editing

llvm-svn: 350048

3 files changed, 19 insertions, 12 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/AddressPool.cpp b/llvm/lib/CodeGen/AsmPrinter/AddressPool.cpp
index 042243b7925..97c08da3827 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AddressPool.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AddressPool.cpp
@@ -27,12 +27,13 @@ unsigned AddressPool::getIndex(const MCSymbol *Sym, bool TLS) {
 
 void AddressPool::emitHeader(AsmPrinter &Asm, MCSection *Section) {
   static const uint8_t AddrSize = Asm.getDataLayout().getPointerSize();
-  uint64_t Length = sizeof(uint16_t) // version
-                  + sizeof(uint8_t)  // address_size
-                  + sizeof(uint8_t)  // segment_selector_size
-                  + AddrSize * Pool.size(); // entries
+  StringRef Prefix = "debug_addr_";
+  MCSymbol *BeginLabel = Asm.createTempSymbol(Prefix + "start");
+  EndLabel = Asm.createTempSymbol(Prefix + "end");
   Asm.OutStreamer->AddComment("Length of contribution");
-  Asm.emitInt32(Length); // TODO: Support DWARF64 format.
+  Asm.EmitLabelDifference(EndLabel, BeginLabel,
+                          4); // TODO: Support DWARF64 format.
+  Asm.OutStreamer->EmitLabel(BeginLabel);
   Asm.OutStreamer->AddComment("DWARF version number");
   Asm.emitInt16(Asm.getDwarfVersion());
   Asm.OutStreamer->AddComment("Address size");
@@ -67,4 +68,6 @@ void AddressPool::emit(AsmPrinter &Asm, MCSection *AddrSection) {
 
   for (const MCExpr *Entry : Entries)
     Asm.OutStreamer->EmitValue(Entry, Asm.getDataLayout().getPointerSize());
+
+  Asm.OutStreamer->EmitLabel(EndLabel);
 }
diff --git a/llvm/lib/CodeGen/AsmPrinter/AddressPool.h b/llvm/lib/CodeGen/AsmPrinter/AddressPool.h
index 2209c7eb50e..e1bf3e9ae58 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AddressPool.h
+++ b/llvm/lib/CodeGen/AsmPrinter/AddressPool.h
@@ -30,6 +30,8 @@ class AddressPool {
   };
   DenseMap<const MCSymbol *, AddressPoolEntry> Pool;
 
+  MCSymbol *EndLabel;
+
   /// Record whether the AddressPool has been queried for an address index since
   /// the last "resetUsedFlag" call. Used to implement type unit fallback - a
   /// type that references addresses cannot be placed in a type unit when using
diff --git a/llvm/test/DebugInfo/X86/addr_comments.ll b/llvm/test/DebugInfo/X86/addr_comments.ll
index 780b37915a4..487973d2267 100644
--- a/llvm/test/DebugInfo/X86/addr_comments.ll
+++ b/llvm/test/DebugInfo/X86/addr_comments.ll
@@ -1,12 +1,14 @@
 ; RUN: llc %s -mtriple=i386-unknown-linux-gnu -filetype=asm -o - | FileCheck %s
 
-; CHECK:   .section .debug_addr
-; CHECK:   .long   8 # Length of contribution
-; CHECK:   .short  5 # DWARF version number
-; CHECK:   .byte   4 # Address size
-; CHECK:   .byte   0 # Segment selector size
-; CHECK: .Laddr_table_base0:
-; CHECK:   .long   .Lfunc_begin0
+; CHECK:      .section .debug_addr
+; CHECK-NEXT:   .long   .Ldebug_addr_end0-.Ldebug_addr_start0 # Length of contribution
+; CHECK-NEXT: .Ldebug_addr_startt 0:
+; CHECK-NEXT:   .short  5 # DWARF version number
+; CHECK-NEXT:   .byte   4 # Address size
+; CHECK-NEXT:   .byte   0 # Segment selector size
+; CHECK-NEXT: .Laddr_table_base0:
+; CHECK-NEXT:   .long   .Lfunc_begin0
+; CHECK-NEXT: .Ldebug_addr_end0:
  
 ; Function Attrs: noinline nounwind optnone uwtable
 define dso_local void @foo() #0 !dbg !7 {