During bottom up fast-isel, instructions emitted to materalize registers are at top of basic block and do not have debug location. This may misguide debugger while entering the basic block and sometimes debugger provides semi useful view of current location to developer by picking up previous known location as current location. Assign a sensible location to the first instruction in a basic block, if it does not have one location derived from source file, so that debugger can provide meaningful user experience to developers in edge cases.

[take 2]


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135423 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 148 insertions, 0 deletions

diff --git a/include/llvm/CodeGen/FastISel.h b/include/llvm/CodeGen/FastISel.h
index 962a4e2635..14960a3808 100644
--- a/include/llvm/CodeGen/FastISel.h
+++ b/include/llvm/CodeGen/FastISel.h
@@ -118,6 +118,10 @@ public:
     DebugLoc DL;
   };
 
+  /// recomputeDebugLocForMaterializedRegs - Recompute debug location for
+  /// very first instruction in a basic block.
+  void recomputeDebugLocForMaterializedRegs();
+
   /// enterLocalValueArea - Prepare InsertPt to begin inserting instructions
   /// into the local value area and return the old insert position.
   SavePoint enterLocalValueArea();
diff --git a/lib/CodeGen/SelectionDAG/FastISel.cpp b/lib/CodeGen/SelectionDAG/FastISel.cpp
index b8d7e82fe3..53809c62f8 100644
--- a/lib/CodeGen/SelectionDAG/FastISel.cpp
+++ b/lib/CodeGen/SelectionDAG/FastISel.cpp
@@ -292,6 +292,28 @@ void FastISel::recomputeInsertPt() {
     ++FuncInfo.InsertPt;
 }
 
+/// recomputeDebugLocForMaterializedRegs - Recompute debug location for
+/// very first instruction in a basic block. All instructions emitted
+/// to materialize registers do not have location information, see
+/// enterLocalValueArea(), becase they may not be emited at the right
+/// location.
+void FastISel::recomputeDebugLocForMaterializedRegs() {
+  if (!getLastLocalValue())
+    return;
+  MachineInstr *First = FuncInfo.MBB->getFirstNonPHI();
+  if (!First->getDebugLoc().isUnknown())
+    return;
+
+  for (MachineBasicBlock::iterator I = FuncInfo.MBB->begin(),
+         E = FuncInfo.MBB->end(); I != E; ++I) {
+    DebugLoc DL = I->getDebugLoc();
+    if (!DL.isUnknown()) {
+      First->setDebugLoc(DL);
+      return;
+    }
+  }
+}
+
 FastISel::SavePoint FastISel::enterLocalValueArea() {
   MachineBasicBlock::iterator OldInsertPt = FuncInfo.InsertPt;
   DebugLoc OldDL = DL;
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index 87bb296b8c..d3cb0fedef 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -964,6 +964,8 @@ void SelectionDAGISel::SelectAllBasicBlocks(const Function &Fn) {
     else
       ++NumFastIselBlocks;
 
+    if (FastIS && LLVMBB != &Fn.getEntryBlock())
+      FastIS->recomputeDebugLocForMaterializedRegs();
     if (Begin != BI) {
       // Run SelectionDAG instruction selection on the remainder of the block
       // not handled by FastISel. If FastISel is not run, this is the entire
diff --git a/test/CodeGen/X86/dbg-materialized-reg-loc.ll b/test/CodeGen/X86/dbg-materialized-reg-loc.ll
new file mode 100644
index 0000000000..9fa6a678f2
--- /dev/null
+++ b/test/CodeGen/X86/dbg-materialized-reg-loc.ll
@@ -0,0 +1,120 @@
+; RUN: llc -O0 < %s | FileCheck %s
+; Radar 9223880
+; CHECK:         .loc    1 17 64
+; CHECK:        movl    $0, %esi
+
+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-macosx10.7.0"
+
+%class.LanguageRuntime = type opaque
+%class.Process = type { i8 }
+
+define zeroext i1 @_Z15SetDynamicValuev() uwtable ssp {
+entry:
+  %retval = alloca i1, align 1
+  %process = alloca %class.Process*, align 8
+  %cpp_runtime = alloca %class.LanguageRuntime*, align 8
+  %objc_runtime = alloca %class.LanguageRuntime*, align 8
+  %call = call zeroext i1 @_Z24IsPointerOrReferenceTypev(), !dbg !15
+  br i1 %call, label %if.end, label %if.then, !dbg !15
+
+if.then:                                          ; preds = %entry
+  store i1 false, i1* %retval, !dbg !17
+  br label %return, !dbg !17
+
+if.end:                                           ; preds = %entry
+  call void @llvm.dbg.declare(metadata !{%class.Process** %process}, metadata !18), !dbg !20
+  %call1 = call %class.Process* @_Z10GetProcessv(), !dbg !21
+  store %class.Process* %call1, %class.Process** %process, align 8, !dbg !21
+  %tmp = load %class.Process** %process, align 8, !dbg !22
+  %tobool = icmp ne %class.Process* %tmp, null, !dbg !22
+  br i1 %tobool, label %if.end3, label %if.then2, !dbg !22
+
+if.then2:                                         ; preds = %if.end
+  store i1 false, i1* %retval, !dbg !23
+  br label %return, !dbg !23
+
+if.end3:                                          ; preds = %if.end
+  call void @llvm.dbg.declare(metadata !{%class.LanguageRuntime** %cpp_runtime}, metadata !24), !dbg !25
+  %tmp5 = load %class.Process** %process, align 8, !dbg !26
+  %call6 = call %class.LanguageRuntime* @_ZN7Process18GetLanguageRuntimeEi(%class.Process* %tmp5, i32 0), !dbg !26
+  store %class.LanguageRuntime* %call6, %class.LanguageRuntime** %cpp_runtime, align 8, !dbg !26
+  %tmp7 = load %class.LanguageRuntime** %cpp_runtime, align 8, !dbg !27
+  %tobool8 = icmp ne %class.LanguageRuntime* %tmp7, null, !dbg !27
+  br i1 %tobool8, label %if.then9, label %if.end10, !dbg !27
+
+if.then9:                                         ; preds = %if.end3
+  store i1 true, i1* %retval, !dbg !28
+  br label %return, !dbg !28
+
+if.end10:                                         ; preds = %if.end3
+  call void @llvm.dbg.declare(metadata !{%class.LanguageRuntime** %objc_runtime}, metadata !30), !dbg !31
+  %tmp12 = load %class.Process** %process, align 8, !dbg !32
+  %call13 = call %class.LanguageRuntime* @_ZN7Process18GetLanguageRuntimeEi(%class.Process* %tmp12, i32 1), !dbg !32
+  store %class.LanguageRuntime* %call13, %class.LanguageRuntime** %objc_runtime, align 8, !dbg !32
+  %tmp14 = load %class.LanguageRuntime** %objc_runtime, align 8, !dbg !33
+  %tobool15 = icmp ne %class.LanguageRuntime* %tmp14, null, !dbg !33
+  br i1 %tobool15, label %if.then16, label %if.end17, !dbg !33
+
+if.then16:                                        ; preds = %if.end10
+  store i1 true, i1* %retval, !dbg !34
+  br label %return, !dbg !34
+
+if.end17:                                         ; preds = %if.end10
+  store i1 false, i1* %retval, !dbg !36
+  br label %return, !dbg !36
+
+return:                                           ; preds = %if.end17, %if.then16, %if.then9, %if.then2, %if.then
+  %0 = load i1* %retval, !dbg !37
+  ret i1 %0, !dbg !37
+}
+
+declare zeroext i1 @_Z24IsPointerOrReferenceTypev()
+
+declare void @llvm.dbg.declare(metadata, metadata) nounwind readnone
+
+declare %class.Process* @_Z10GetProcessv()
+
+declare %class.LanguageRuntime* @_ZN7Process18GetLanguageRuntimeEi(%class.Process*, i32)
+
+!llvm.dbg.cu = !{!0}
+!llvm.dbg.sp = !{!1, !6}
+
+!0 = metadata !{i32 589841, i32 0, i32 4, metadata !"my_vo.cpp", metadata !"/private/tmp", metadata !"clang version 3.0 (trunk 133629)", i1 true, i1 false, metadata !"", i32 0} ; [ DW_TAG_compile_unit ]
+!1 = metadata !{i32 589870, i32 0, metadata !2, metadata !"SetDynamicValue", metadata !"SetDynamicValue", metadata !"_Z15SetDynamicValuev", metadata !2, i32 9, metadata !3, i1 false, i1 true, i32 0, i32 0, i32 0, i32 256, i1 false, i1 ()* @_Z15SetDynamicValuev, null, null} ; [ DW_TAG_subprogram ]
+!2 = metadata !{i32 589865, metadata !"my_vo.cpp", metadata !"/private/tmp", metadata !0} ; [ DW_TAG_file_type ]
+!3 = metadata !{i32 589845, metadata !2, metadata !"", metadata !2, i32 0, i64 0, i64 0, i32 0, i32 0, i32 0, metadata !4, i32 0, i32 0} ; [ DW_TAG_subroutine_type ]
+!4 = metadata !{metadata !5}
+!5 = metadata !{i32 589860, metadata !0, metadata !"bool", null, i32 0, i64 8, i64 8, i64 0, i32 0, i32 2} ; [ DW_TAG_base_type ]
+!6 = metadata !{i32 589870, i32 0, metadata !7, metadata !"GetLanguageRuntime", metadata !"GetLanguageRuntime", metadata !"_ZN7Process18GetLanguageRuntimeEi", metadata !2, i32 4, metadata !9, i1 false, i1 false, i32 0, i32 0, null, i32 256, i1 false, null, null} ; [ DW_TAG_subprogram ]
+!7 = metadata !{i32 589826, metadata !0, metadata !"Process", metadata !2, i32 2, i64 8, i64 8, i32 0, i32 0, null, metadata !8, i32 0, null, null} ; [ DW_TAG_class_type ]
+!8 = metadata !{metadata !6}
+!9 = metadata !{i32 589845, metadata !2, metadata !"", metadata !2, i32 0, i64 0, i64 0, i32 0, i32 0, i32 0, metadata !10, i32 0, i32 0} ; [ DW_TAG_subroutine_type ]
+!10 = metadata !{metadata !11, metadata !13, metadata !14}
+!11 = metadata !{i32 589839, metadata !0, metadata !"", null, i32 0, i64 64, i64 64, i64 0, i32 0, metadata !12} ; [ DW_TAG_pointer_type ]
+!12 = metadata !{i32 589843, metadata !0, metadata !"LanguageRuntime", metadata !2, i32 1, i64 0, i64 0, i32 0, i32 4, i32 0, null, i32 0, i32 0} ; [ DW_TAG_structure_type ]
+!13 = metadata !{i32 589839, metadata !0, metadata !"", i32 0, i32 0, i64 64, i64 64, i64 0, i32 64, metadata !7} ; [ DW_TAG_pointer_type ]
+!14 = metadata !{i32 589860, metadata !0, metadata !"int", null, i32 0, i64 32, i64 32, i64 0, i32 0, i32 5} ; [ DW_TAG_base_type ]
+!15 = metadata !{i32 10, i32 3, metadata !16, null}
+!16 = metadata !{i32 589835, metadata !1, i32 9, i32 24, metadata !2, i32 0} ; [ DW_TAG_lexical_block ]
+!17 = metadata !{i32 11, i32 5, metadata !16, null}
+!18 = metadata !{i32 590080, metadata !16, metadata !"process", metadata !2, i32 13, metadata !19, i32 0} ; [ DW_TAG_auto_variable ]
+!19 = metadata !{i32 589839, metadata !0, metadata !"", null, i32 0, i64 64, i64 64, i64 0, i32 0, metadata !7} ; [ DW_TAG_pointer_type ]
+!20 = metadata !{i32 13, i32 12, metadata !16, null}
+!21 = metadata !{i32 13, i32 34, metadata !16, null}
+!22 = metadata !{i32 14, i32 3, metadata !16, null}
+!23 = metadata !{i32 15, i32 5, metadata !16, null}
+!24 = metadata !{i32 590080, metadata !16, metadata !"cpp_runtime", metadata !2, i32 17, metadata !11, i32 0} ; [ DW_TAG_auto_variable ]
+!25 = metadata !{i32 17, i32 20, metadata !16, null}
+!26 = metadata !{i32 17, i32 64, metadata !16, null}
+!27 = metadata !{i32 18, i32 3, metadata !16, null}
+!28 = metadata !{i32 19, i32 5, metadata !29, null}
+!29 = metadata !{i32 589835, metadata !16, i32 18, i32 20, metadata !2, i32 1} ; [ DW_TAG_lexical_block ]
+!30 = metadata !{i32 590080, metadata !16, metadata !"objc_runtime", metadata !2, i32 22, metadata !11, i32 0} ; [ DW_TAG_auto_variable ]
+!31 = metadata !{i32 22, i32 20, metadata !16, null}
+!32 = metadata !{i32 22, i32 65, metadata !16, null}
+!33 = metadata !{i32 23, i32 3, metadata !16, null}
+!34 = metadata !{i32 24, i32 5, metadata !35, null}
+!35 = metadata !{i32 589835, metadata !16, i32 23, i32 21, metadata !2, i32 2} ; [ DW_TAG_lexical_block ]
+!36 = metadata !{i32 26, i32 3, metadata !16, null}
+!37 = metadata !{i32 27, i32 1, metadata !16, null}