Revert "DwarfDebug: Pick next location in case of missing location at block begin"

It originally triggered a stepping problem in the debugger, which could
be fixed by adjusting CodeGen/LexicalScopes.cpp however it seems we prefer
the previous behavior anyway.

See the discussion for details: http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20181008/593833.html

This reverts commit r343880.
This reverts commit r343874.

llvm-svn: 344318

2 files changed, 6 insertions, 79 deletions

diff --git a/llvm/test/DebugInfo/X86/dwarf-no-source-loc.ll b/llvm/test/DebugInfo/X86/dwarf-no-source-loc.ll
index 19695ab126b..60d50a391a1 100644
--- a/llvm/test/DebugInfo/X86/dwarf-no-source-loc.ll
+++ b/llvm/test/DebugInfo/X86/dwarf-no-source-loc.ll
@@ -40,14 +40,15 @@ if.end:                                           ; preds = %if.then, %entry
   ret void, !dbg !14
 }
 
-; CHECK:      .loc 1 7 7 prologue_end
+; CHECK:      .loc 1 7 7
 ; CHECK-NOT:  .loc
-; CHECK:      # %bb.1
-; CHECK-NEXT: .file 2 "/tests{{[/\]+}}include.h"
-; CHECK-NEXT: .loc 2 20 5
+; CHECK:      .loc 1 0 7 is_stmt 0
 ; CHECK-NOT:  .loc
+; CHECK:      .loc 2 20 5 is_stmt 1
 ; CHECK:      .LBB0_2:
-; CHECK:      .loc 1 10 3
+; CHECK-NEXT: .loc 2 0 5 is_stmt 0
+; CHECK-NOT:  .loc
+; CHECK:      .loc 1 10 3 is_stmt 1
 ;
 ; DISABLE-NOT: .loc 1 0
 
diff --git a/llvm/test/DebugInfo/X86/dwarf-no-source-loc.mir b/llvm/test/DebugInfo/X86/dwarf-no-source-loc.mir
deleted file mode 100644
index f6ad6ee6d4c..00000000000
--- a/llvm/test/DebugInfo/X86/dwarf-no-source-loc.mir
+++ /dev/null
@@ -1,74 +0,0 @@
-# RUN: llc -o - %s -start-before=patchable-function -use-unknown-locations=Default | FileCheck %s --check-prefixes=CHECK,DEFAULT
-# RUN: llc -o - %s -start-before=patchable-function -use-unknown-locations=Enable | FileCheck %s --check-prefixes=CHECK,ENABLE
-# RUN: llc -o - %s -start-before=patchable-function -use-unknown-locations=Disable | FileCheck %s --check-prefixes=CHECK,DISABLE
---- |
-  target triple = "x86_64--"
-  
-  !0 = !DIFile(filename: "dwarf-no-source-loc.mir", directory: "/")
-  !1 = distinct !DICompileUnit(file: !0, language: DW_LANG_C, emissionKind: LineTablesOnly)
-  !2 = distinct !DISubprogram(name: "func", unit: !1)
-  !3 = !DILocation(line: 17, scope: !2)
-  !4 = !DILocation(line: 42, scope: !2)
-
-  !llvm.dbg.cu = !{!1}
-  !llvm.module.flags = !{!10, !11}
-  !10 = !{i32 2, !"Dwarf Version", i32 4}
-  !11 = !{i32 2, !"Debug Info Version", i32 3}
-  
-  define void @func() !dbg !2 {
-    unreachable
-  }
-...
----
-name: func
-body: |
-  bb.0:
-    NOOP
-    NOOP
-    $eax = MOV32ri 1, debug-location !3
-    ; CHECK-LABEL: bb.0
-    ; CHECK: nop
-    ; CHECK: nop
-    ; CHECK: .loc 1 17 0 prologue_end
-    ; CHECK: movl $1, %eax
-
-  bb.1:
-    NOOP
-    $ebx = MOV32ri 2, debug-location !4
-    ; CHECK-LABEL: bb.1
-    ; DEFAULT: .loc 1 42 0
-    ; ENABLE: .loc 1 0
-    ; DISABLE-NOT: .loc 1 0
-    ; CHECK: nop
-    ; ENABLE: .loc 1 42 0
-    ; CHECK: movl $2, %ebx
-
-  bb.2:
-    NOOP
-    ; CHECK-LABEL: bb.2
-    ; DEFAULT: .loc 1 0 0 is_stmt 0
-    ; ENABLE: .loc 1 0 0 is_stmt 0
-    ; DISABLE-NOT: .loc 1 0
-    ; CHECK: nop
-
-  bb.3:
-    NOOP
-    $ecx = MOV32ri 3, debug-location !3
-    ; CHECK-LABEL: bb.3
-    ; CHECK: nop
-    ; DEFAULT: .loc 1 17 0 is_stmt 1
-    ; ENABLE: .loc 1 17 0 is_stmt 1
-    ; DISABLE-NOT: .loc 1 0
-    ; CHECK: movl $3, %ecx
-
-  bb.4:
-    NOOP
-    $edx = MOV32ri 4, debug-location !4
-    ; CHECK: bb.4
-    ; DEFAULT: .loc 1 42 0
-    ; ENABLE: .loc 1 0 0 is_stmt 0
-    ; DISABLE-NOT: .loc 1 0
-    ; CHECK: nop
-    ; ENABLE: .loc 1 42 0 is_stmt 1
-    ; CHECK: movl $4, %edx
-...