Use DW_FORM_sdata for signed constant values and udata on occasion

when we can. Migrate from using blocks when we're adding just a
single attribute and floating point values are an unsigned, not signed,
bag of bits.

Update all test cases accordingly.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189419 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 65 insertions, 30 deletions

diff --git a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
index 8cef3e2b25..7b3842811a 100644
--- a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -606,21 +606,36 @@ void CompileUnit::addConstantValue(DIE *Die, const MachineOperand &MO,
   // their maximum bit width which is a bit unfortunate (& doesn't prefer
   // udata/sdata over dataN as suggested by the DWARF spec)
   assert(MO.isImm() && "Invalid machine operand!");
-  DIEBlock *Block = new (DIEValueAllocator) DIEBlock();
   int SizeInBits = -1;
   bool SignedConstant = isTypeSigned(Ty, &SizeInBits);
-  uint16_t Form = SignedConstant ? dwarf::DW_FORM_sdata : dwarf::DW_FORM_udata;
-  switch (SizeInBits) {
-    case 8:  Form = dwarf::DW_FORM_data1; break;
-    case 16: Form = dwarf::DW_FORM_data2; break;
-    case 32: Form = dwarf::DW_FORM_data4; break;
-    case 64: Form = dwarf::DW_FORM_data8; break;
-    default: break;
+  uint16_t Form;
+
+  // If we're a signed constant definitely use sdata.
+  if (SignedConstant) {
+    addSInt(Die, dwarf::DW_AT_const_value, dwarf::DW_FORM_sdata, MO.getImm());
+    return;
   }
-  SignedConstant ? addSInt(Block, 0, Form, MO.getImm())
-    : addUInt(Block, 0, Form, MO.getImm());
 
-  addBlock(Die, dwarf::DW_AT_const_value, 0, Block);
+  // Else use data for now unless it's larger than we can deal with.
+  switch (SizeInBits) {
+  case 8:
+    Form = dwarf::DW_FORM_data1;
+    break;
+  case 16:
+    Form = dwarf::DW_FORM_data2;
+    break;
+  case 32:
+    Form = dwarf::DW_FORM_data4;
+    break;
+  case 64:
+    Form = dwarf::DW_FORM_data8;
+    break;
+  default:
+    Form = dwarf::DW_FORM_udata;
+    addUInt(Die, dwarf::DW_AT_const_value, Form, MO.getImm());
+    return;
+  }
+  addUInt(Die, dwarf::DW_AT_const_value, Form, MO.getImm());
 }
 
 /// addConstantFPValue - Add constant value entry in variable DIE.
@@ -649,7 +664,8 @@ void CompileUnit::addConstantFPValue(DIE *Die, const MachineOperand &MO) {
 
 /// addConstantFPValue - Add constant value entry in variable DIE.
 void CompileUnit::addConstantFPValue(DIE *Die, const ConstantFP *CFP) {
-  addConstantValue(Die, CFP->getValueAPF().bitcastToAPInt(), false);
+  // Pass this down to addConstantValue as an unsigned bag of bits.
+  addConstantValue(Die, CFP->getValueAPF().bitcastToAPInt(), true);
 }
 
 /// addConstantValue - Add constant value entry in variable DIE.
@@ -662,19 +678,34 @@ void CompileUnit::addConstantValue(DIE *Die, const ConstantInt *CI,
 void CompileUnit::addConstantValue(DIE *Die, const APInt &Val, bool Unsigned) {
   unsigned CIBitWidth = Val.getBitWidth();
   if (CIBitWidth <= 64) {
-    unsigned form = 0;
+    // If we're a signed constant definitely use sdata.
+    if (!Unsigned) {
+      addSInt(Die, dwarf::DW_AT_const_value, dwarf::DW_FORM_sdata,
+              Val.getSExtValue());
+      return;
+    }
+
+    // Else use data for now unless it's larger than we can deal with.
+    uint16_t Form;
     switch (CIBitWidth) {
-    case 8: form = dwarf::DW_FORM_data1; break;
-    case 16: form = dwarf::DW_FORM_data2; break;
-    case 32: form = dwarf::DW_FORM_data4; break;
-    case 64: form = dwarf::DW_FORM_data8; break;
+    case 8:
+      Form = dwarf::DW_FORM_data1;
+      break;
+    case 16:
+      Form = dwarf::DW_FORM_data2;
+      break;
+    case 32:
+      Form = dwarf::DW_FORM_data4;
+      break;
+    case 64:
+      Form = dwarf::DW_FORM_data8;
+      break;
     default:
-      form = Unsigned ? dwarf::DW_FORM_udata : dwarf::DW_FORM_sdata;
+      addUInt(Die, dwarf::DW_AT_const_value, dwarf::DW_FORM_udata,
+              Val.getZExtValue());
+      return;
     }
-    if (Unsigned)
-      addUInt(Die, dwarf::DW_AT_const_value, form, Val.getZExtValue());
-    else
-      addSInt(Die, dwarf::DW_AT_const_value, form, Val.getSExtValue());
+    addUInt(Die, dwarf::DW_AT_const_value, Form, Val.getZExtValue());
     return;
   }
 
diff --git a/test/DebugInfo/X86/dbg-const-int.ll b/test/DebugInfo/X86/dbg-const-int.ll
index 4ff0301bc1..7b6c40cc0a 100644
--- a/test/DebugInfo/X86/dbg-const-int.ll
+++ b/test/DebugInfo/X86/dbg-const-int.ll
@@ -1,9 +1,13 @@
-; RUN: llc < %s - | FileCheck %s
+; RUN: llc -mtriple=x86_64-apple-darwin12 -filetype=obj %s -o %t
+; RUN: llvm-dwarfdump %t | FileCheck %s
 target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
 target triple = "x86_64-apple-macosx10.6.7"
 ; Radar 9511391
 
-;CHECK:         .byte   4                       ## DW_AT_const_value
+; CHECK: DW_TAG_variable
+; CHECK: "i"
+; CHECK: DW_AT_const_value [DW_FORM_sdata]   (42)
+
 define i32 @foo() nounwind uwtable readnone optsize ssp {
 entry:
   tail call void @llvm.dbg.value(metadata !8, i64 0, metadata !6), !dbg !9
diff --git a/test/DebugInfo/X86/debug-info-static-member.ll b/test/DebugInfo/X86/debug-info-static-member.ll
index cda725a7ff..4378115c6f 100644
--- a/test/DebugInfo/X86/debug-info-static-member.ll
+++ b/test/DebugInfo/X86/debug-info-static-member.ll
@@ -120,7 +120,7 @@ declare void @llvm.dbg.declare(metadata, metadata) nounwind readnone
 ; PRESENT:      DW_TAG_member
 ; PRESENT-NEXT: DW_AT_name {{.*}} "const_c"
 ; PRESENT:      DW_AT_accessibility [DW_FORM_data1]   (0x01)
-; PRESENT:      DW_AT_const_value {{.*}} (0x00000012)
+; PRESENT:      DW_AT_const_value {{.*}} (18)
 ; While we're here, a normal member has data_member_location and
 ; accessibility attributes.
 ; PRESENT:      DW_TAG_member
@@ -173,7 +173,7 @@ declare void @llvm.dbg.declare(metadata, metadata) nounwind readnone
 ; DARWINP:      DW_TAG_member
 ; DARWINP-NEXT: DW_AT_name {{.*}} "const_c"
 ; DARWINP:      DW_AT_accessibility [DW_FORM_data1]   (0x01)
-; DARWINP:      DW_AT_const_value {{.*}} (0x00000012)
+; DARWINP:      DW_AT_const_value {{.*}} (18)
 ; While we're here, a normal member has data_member_location and
 ; accessibility attributes.
 ; DARWINP:      DW_TAG_member
diff --git a/test/DebugInfo/X86/multiple-at-const-val.ll b/test/DebugInfo/X86/multiple-at-const-val.ll
index 13fa48b109..e966fc0509 100644
--- a/test/DebugInfo/X86/multiple-at-const-val.ll
+++ b/test/DebugInfo/X86/multiple-at-const-val.ll
@@ -8,7 +8,7 @@
 ; CHECK: DW_TAG_class_type
 ; CHECK: DW_TAG_member
 ; CHECK: badbit
-; CHECK: DW_AT_const_value [DW_FORM_data4]	(0x00000001)
+; CHECK: DW_AT_const_value [DW_FORM_sdata]      (1)
 ; CHECK-NOT: DW_AT_const_value
 ; CHECK: NULL
 
diff --git a/test/DebugInfo/X86/template.ll b/test/DebugInfo/X86/template.ll
index 16808e1e4c..e7aff79b7c 100644
--- a/test/DebugInfo/X86/template.ll
+++ b/test/DebugInfo/X86/template.ll
@@ -27,7 +27,7 @@
 ; even as data1. DWARF strongly urges implementations to prefer 
 ; _sdata/_udata rather than dataN
 
-; CHECK-NEXT: DW_AT_const_value [DW_FORM_data4]{{.*}}(0x00000003)
+; CHECK-NEXT: DW_AT_const_value [DW_FORM_sdata]{{.*}}(3)
 
 ; CHECK: DW_TAG_template_value_parameter
 ; CHECK-NEXT: DW_AT_type{{.*}}=> {[[INTPTR:0x[0-9a-f]*]]}
@@ -47,11 +47,11 @@
 ; CHECK-NOT: NULL
 ; CHECK: DW_TAG_template_value_parameter
 ; CHECK-NEXT: DW_AT_type{{.*}}=> {[[INT]]}
-; CHECK-NEXT: DW_AT_const_value  [DW_FORM_data4]{{.*}}(0x00000001)
+; CHECK-NEXT: DW_AT_const_value  [DW_FORM_sdata]{{.*}}(1)
 ; CHECK-NOT: NULL
 ; CHECK: DW_TAG_template_value_parameter
 ; CHECK-NEXT: DW_AT_type{{.*}}=> {[[INT]]}
-; CHECK-NEXT: DW_AT_const_value  [DW_FORM_data4]{{.*}}(0x00000002)
+; CHECK-NEXT: DW_AT_const_value  [DW_FORM_sdata]{{.*}}(2)
 
 ; CHECK: [[INTPTR]]:{{ *}}DW_TAG_pointer_type
 ; CHECK-NEXT: DW_AT_type{{.*}} => {[[INT]]}