From e2ad73759d80376f3d450d05843bd86ac408c221 Mon Sep 17 00:00:00 2001
From: David Majnemer <david.majnemer@gmail.com>
Date: Wed, 24 Feb 2016 10:01:24 +0000
Subject: [PATCH] [CodeView] Describe variables live in x87 registers

We didn't have a mapping from LLVM's x87 floating point registers to
CodeView's encoding.

llvm-svn: 261730
---
 .../X86/MCTargetDesc/X86MCTargetDesc.cpp      |  5 ++
 llvm/test/DebugInfo/COFF/fp-stack.ll          | 47 +++++++++++++++++++
 2 files changed, 52 insertions(+)
 create mode 100644 llvm/test/DebugInfo/COFF/fp-stack.ll

diff --git a/llvm/lib/Target/X86/MCTargetDesc/X86MCTargetDesc.cpp b/llvm/lib/Target/X86/MCTargetDesc/X86MCTargetDesc.cpp
index 362beaceed9f..e12782b8d601 100644
--- a/llvm/lib/Target/X86/MCTargetDesc/X86MCTargetDesc.cpp
+++ b/llvm/lib/Target/X86/MCTargetDesc/X86MCTargetDesc.cpp
@@ -84,6 +84,11 @@ void X86_MC::initLLVMToSEHAndCVRegMapping(MCRegisterInfo *MRI) {
   for (unsigned I = 0; I < array_lengthof(LowCVRegs); ++I)
     MRI->mapLLVMRegToCVReg(LowCVRegs[I], I + CVLowRegStart);
 
+  // The x86 registers start at 128 and are numbered sequentially.
+  unsigned FP0Start = 128;
+  for (unsigned I = 0; I < 8; ++I)
+    MRI->mapLLVMRegToCVReg(X86::FP0 + I, FP0Start + I);
+
   // The low 8 XMM registers start at 154 and are numbered sequentially.
   unsigned CVXMM0Start = 154;
   for (unsigned I = 0; I < 8; ++I)
diff --git a/llvm/test/DebugInfo/COFF/fp-stack.ll b/llvm/test/DebugInfo/COFF/fp-stack.ll
new file mode 100644
index 000000000000..2731660d82ff
--- /dev/null
+++ b/llvm/test/DebugInfo/COFF/fp-stack.ll
@@ -0,0 +1,47 @@
+; RUN: llc -mtriple=i686-windows-msvc < %s | FileCheck %s --check-prefix=ASM
+; RUN: llc -mtriple=i686-windows-msvc < %s -filetype=obj | llvm-readobj -codeview - | FileCheck %s --check-prefix=OBJ
+target datalayout = "e-m:x-p:32:32-i64:64-f80:32-n8:16:32-a:0:32-S32"
+target triple = "i686-pc-windows-msvc18.0.0"
+
+define double @f(double %p1) !dbg !4 {
+entry:
+  %sub = fsub double -0.000000e+00, %p1, !dbg !16
+  tail call void @llvm.dbg.value(metadata double %sub, i64 0, metadata !10, metadata !14), !dbg !15
+  ret double %sub
+}
+
+; ASM:         .cv_def_range    Lfunc_begin0 Lfunc_end0, "A\021\200\000\000\000"
+; OBJ:    DefRangeRegister {
+; OBJ:      Register: 128
+; OBJ:      MayHaveNoName: 0
+; OBJ:      LocalVariableAddrRange {
+; OBJ:        OffsetStart: .text+0x0
+; OBJ:        ISectStart: 0x0
+; OBJ:        Range: 0x7
+; OBJ:      }
+; OBJ:    }
+
+; Function Attrs: nounwind readnone
+declare void @llvm.dbg.value(metadata, i64, metadata, metadata)
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!11, !12}
+!llvm.ident = !{!13}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 3.9.0 (trunk 261537) (llvm/trunk 261463)", isOptimized: true, runtimeVersion: 0, emissionKind: 1, enums: !2, subprograms: !3)
+!1 = !DIFile(filename: "<stdin>", directory: "/")
+!2 = !{}
+!3 = !{!4}
+!4 = distinct !DISubprogram(name: "f", linkageName: "f", scope: !5, file: !5, line: 2, type: !6, isLocal: false, isDefinition: true, scopeLine: 2, flags: DIFlagPrototyped, isOptimized: true, variables: !9)
+!5 = !DIFile(filename: "t.ii", directory: "/")
+!6 = !DISubroutineType(types: !7)
+!7 = !{null, !8}
+!8 = !DIBasicType(name: "double", size: 64, align: 64, encoding: DW_ATE_float)
+!9 = !{!10}
+!10 = !DILocalVariable(name: "p1", arg: 1, scope: !4, file: !5, line: 2, type: !8)
+!11 = !{i32 2, !"CodeView", i32 1}
+!12 = !{i32 2, !"Debug Info Version", i32 3}
+!13 = !{!"clang version 3.9.0 (trunk 261537) (llvm/trunk 261463)"}
+!14 = !DIExpression()
+!15 = !DILocation(line: 2, scope: !4)
+!16 = !DILocation(line: 3, scope: !4)