From 7e4820c1a6a9d561b5ca989bed0425f7f97c0537 Mon Sep 17 00:00:00 2001
From: Rafael Espindola <rafael.espindola@gmail.com>
Date: Tue, 17 Mar 2015 21:30:21 +0000
Subject: [PATCH] Emit the offset directly instead of creating a dummy
 expression.
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

We were creating an expression of the form (S+C)-S which is just C.

Patch by Frédéric Riss. I just added the testcase.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232549 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/AsmPrinter/DIE.cpp            | 27 +----------------------
 test/DebugInfo/X86/ref_addr_relocation.ll |  5 +++++
 2 files changed, 6 insertions(+), 26 deletions(-)

diff --git a/lib/CodeGen/AsmPrinter/DIE.cpp b/lib/CodeGen/AsmPrinter/DIE.cpp
index fe99c5c1c7f..d5ad1711044 100644
--- a/lib/CodeGen/AsmPrinter/DIE.cpp
+++ b/lib/CodeGen/AsmPrinter/DIE.cpp
@@ -381,29 +381,6 @@ void DIEString::print(raw_ostream &O) const {
 // DIEEntry Implementation
 //===----------------------------------------------------------------------===//
 
-/// Emit something like ".long Hi+Offset-Lo" where the size in bytes of the
-/// directive is specified by Size and Hi/Lo specify the labels.
-static void emitLabelOffsetDifference(MCStreamer &Streamer, const MCSymbol *Hi,
-                                      uint64_t Offset, const MCSymbol *Lo,
-                                      unsigned Size) {
-  MCContext &Context = Streamer.getContext();
-
-  // Emit Hi+Offset - Lo
-  // Get the Hi+Offset expression.
-  const MCExpr *Plus =
-      MCBinaryExpr::CreateAdd(MCSymbolRefExpr::Create(Hi, Context),
-                              MCConstantExpr::Create(Offset, Context), Context);
-
-  // Get the Hi+Offset-Lo expression.
-  const MCExpr *Diff = MCBinaryExpr::CreateSub(
-      Plus, MCSymbolRefExpr::Create(Lo, Context), Context);
-
-  // Otherwise, emit with .set (aka assignment).
-  MCSymbol *SetLabel = Context.CreateTempSymbol();
-  Streamer.EmitAssignment(SetLabel, Diff);
-  Streamer.EmitSymbolValue(SetLabel, Size);
-}
-
 /// EmitValue - Emit debug information entry offset.
 ///
 void DIEEntry::EmitValue(const AsmPrinter *AP, dwarf::Form Form) const {
@@ -422,9 +399,7 @@ void DIEEntry::EmitValue(const AsmPrinter *AP, dwarf::Form Form) const {
       AP->EmitLabelPlusOffset(CU->getSectionSym(), Addr,
                               DIEEntry::getRefAddrSize(AP));
     else
-      emitLabelOffsetDifference(AP->OutStreamer, CU->getSectionSym(), Addr,
-                                CU->getSectionSym(),
-                                DIEEntry::getRefAddrSize(AP));
+      AP->OutStreamer.EmitIntValue(Addr, DIEEntry::getRefAddrSize(AP));
   } else
     AP->EmitInt32(Entry.getOffset());
 }
diff --git a/test/DebugInfo/X86/ref_addr_relocation.ll b/test/DebugInfo/X86/ref_addr_relocation.ll
index 4cf7abcb6a9..046419062ec 100644
--- a/test/DebugInfo/X86/ref_addr_relocation.ll
+++ b/test/DebugInfo/X86/ref_addr_relocation.ll
@@ -2,6 +2,7 @@
 ; RUN: llc -filetype=obj -O0 %s -mtriple=x86_64-linux-gnu -o %t
 ; RUN: llvm-dwarfdump %t | FileCheck %s -check-prefix=CHECK-DWARF
 
+; RUN: llc -filetype=asm -O0 -mtriple=x86_64-apple-darwin < %s | FileCheck --check-prefix=DARWIN-ASM %s
 ; RUN: llc -filetype=obj %s -mtriple=x86_64-apple-darwin -o %t2
 ; RUN: llvm-dwarfdump %t2 | FileCheck %s -check-prefix=DARWIN-DWARF
 
@@ -33,6 +34,10 @@
 ; CHECK-NOT: DW_TAG_structure_type
 ; CHECK: .section
 
+; test that we don't create useless labels
+; DARWIN-ASM: .long [[TYPE:.*]] ## DW_AT_type
+; DARWIN-ASM: .quad [[TYPE]] ## DW_AT_type
+
 ; CHECK-DWARF: DW_TAG_compile_unit
 ; CHECK-DWARF: 0x[[ADDR:.*]]: DW_TAG_structure_type
 ; CHECK-DWARF: DW_TAG_compile_unit