[DWARF] Fix a few corner cases in expression emission

Summary: I noticed an object file with `DW_OP_reg4 DW_OP_breg4 0` as a DWARF expression,
which I traced to a missing break (and `++I`) in this code snippet.
While I was at it, I also added support for a few other corner cases
along the same lines that I could think of.

Test Plan: Hand-crafted test case to exercises these cases is included.

Reviewers: echristo, dblaikie, aprantl

Reviewed By: aprantl

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D10302

llvm-svn: 239380

1 files changed, 110 insertions, 0 deletions

diff --git a/llvm/test/DebugInfo/expressions.ll b/llvm/test/DebugInfo/expressions.ll
new file mode 100644
index 00000000000..eb018d94736
--- /dev/null
+++ b/llvm/test/DebugInfo/expressions.ll
@@ -0,0 +1,110 @@
+; REQUIRES: object-emission
+; RUN: %llc_dwarf -mtriple x86_64-apple-darwin14.0.0-elf -filetype=obj %s -o %t
+; RUN: %llc_dwarf -mtriple x86_64-apple-darwin14.0.0-elf -O0 -filetype=obj %s -o %t0
+; RUN: llvm-dwarfdump -debug-dump=loc %t | FileCheck %s
+; RUN: llvm-dwarfdump -debug-dump=loc %t0 | FileCheck -check-prefix CHECK-O0 %s
+
+; CHECK: 0x00000000: Beginning address offset: 0x0000000000000000
+; CHECK:                Ending address offset: 0x[[END:[0-9a-f]+]]
+; CHECK:                 Location description:
+; CHECK-NOT:                                   75 00 55
+; CHECK-SAME:                                  55
+; CHECK: 0x00000023: Beginning address offset: 0x0000000000000000
+; CHECK:                Ending address offset: 0x{{.*}}[[END]]
+; CHECK:                 Location description: 75 08 9f
+; CHECK: 0x00000048: Beginning address offset: 0x0000000000000000
+; CHECK:                Ending address offset: 0x{{.*}}[[END]]
+; CHECK:                 Location description: 75 10 9f
+; CHECK: 0x0000006d: Beginning address offset: 0x0000000000000000
+; CHECK:                Ending address offset: 0x{{.*}}[[END]]
+; CHECK:                 Location description: 75 18
+
+
+; CHECK-O0: 0x00000000: Beginning address offset: 0x0000000000000000
+; CHECK-O0:                Ending address offset: 0x000000000000001b
+; CHECK-O0:                 Location description: 55
+; CHECK-O0:             Beginning address offset: 0x000000000000001b
+; CHECK-O0:                Ending address offset: 0x0000000000000024
+; CHECK-O0:                 Location description: 54
+; CHECK-O0:             Beginning address offset: 0x0000000000000024
+; CHECK-O0:                Ending address offset: 0x0000000000000025
+; CHECK-O0:                 Location description: 77 78 23 00
+; CHECK-O0: 0x0000004c: Beginning address offset: 0x0000000000000000
+; CHECK-O0:                Ending address offset: 0x000000000000001b
+; CHECK-O0:                 Location description: 75 08 9f
+; CHECK-O0:             Beginning address offset: 0x000000000000001b
+; CHECK-O0:                Ending address offset: 0x0000000000000024
+; CHECK-O0:                 Location description: 74 08 9f
+; CHECK-O0:             Beginning address offset: 0x0000000000000024
+; CHECK-O0:                Ending address offset: 0x0000000000000025
+; CHECK-O0:                 Location description: 77 78 23 08
+; CHECK-O0: 0x0000009c: Beginning address offset: 0x0000000000000000
+; CHECK-O0:                Ending address offset: 0x000000000000001b
+; CHECK-O0:                 Location description: 75 10 9f
+; CHECK-O0:             Beginning address offset: 0x000000000000001b
+; CHECK-O0:                Ending address offset: 0x0000000000000024
+; CHECK-O0:                 Location description: 74 10 9f
+; CHECK-O0:             Beginning address offset: 0x0000000000000024
+; CHECK-O0:                Ending address offset: 0x0000000000000025
+; CHECK-O0:                 Location description: 77 78 23 08 23 08
+; CHECK-O0: 0x000000ee: Beginning address offset: 0x0000000000000000
+; CHECK-O0:                Ending address offset: 0x000000000000001b
+; CHECK-O0:                 Location description: 75 18
+; CHECK-O0:             Beginning address offset: 0x000000000000001b
+; CHECK-O0:                Ending address offset: 0x0000000000000024
+; CHECK-O0:                 Location description: 74 18
+; CHECK-O0:             Beginning address offset: 0x0000000000000024
+; CHECK-O0:                Ending address offset: 0x0000000000000025
+; CHECK-O0:                 Location description: 77 78 23 10 23 08 06
+
+declare void @llvm.dbg.value(metadata, i64, metadata, metadata) #0
+
+define float @foo(float* %args, float *%args2)
+{
+    call void @llvm.dbg.value(metadata float* %args, i64 0, metadata !11, metadata !12), !dbg !19
+    call void @llvm.dbg.value(metadata float* %args, i64 0, metadata !13, metadata !14), !dbg !19
+    call void @llvm.dbg.value(metadata float* %args, i64 0, metadata !15, metadata !16), !dbg !19
+    call void @llvm.dbg.value(metadata float* %args, i64 0, metadata !17, metadata !18), !dbg !19
+    %a = load float, float* %args, !dbg !19
+    %bptr = getelementptr float, float* %args, i32 1, !dbg !19
+    %b = load float, float* %bptr, !dbg !19
+    %cptr = getelementptr float, float* %args, i32 2, !dbg !19
+    %c = load float, float* %cptr, !dbg !19
+    %dptr = getelementptr float, float* %args, i32 3, !dbg !19
+    %d = load float, float* %dptr, !dbg !19
+    %ret1 = fadd float %a, %b, !dbg !19
+    %ret2 = fadd float %c, %d, !dbg !19
+    call void @llvm.dbg.value(metadata float* %args2, i64 0, metadata !11, metadata !12), !dbg !19
+    call void @llvm.dbg.value(metadata float* %args2, i64 0, metadata !13, metadata !14), !dbg !19
+    call void @llvm.dbg.value(metadata float* %args2, i64 0, metadata !15, metadata !16), !dbg !19
+    call void @llvm.dbg.value(metadata float* %args2, i64 0, metadata !17, metadata !18), !dbg !19
+    %ret  = fsub float %ret1, %ret2, !dbg !19
+    ret float %ret, !dbg !19
+}
+
+attributes #0 = { nounwind readnone }
+
+!llvm.module.flags = !{!0, !1}
+!llvm.dbg.cu = !{!2}
+
+!0 = !{i32 2, !"Dwarf Version", i32 4}
+!1 = !{i32 1, !"Debug Info Version", i32 3}
+
+!2 = !DICompileUnit(language: DW_LANG_C89, file: !3, producer: "byHand", isOptimized: true, runtimeVersion: 0, emissionKind: 1, enums: !4, retainedTypes: !4, subprograms: !5, globals: !4, imports: !4)
+!3 = !DIFile(filename: "expressions", directory: ".")
+!4 = !{}
+!5 = !{!6}
+!6 = !DISubprogram(name: "foo", linkageName: "foo", scope: null, file: !3, type: !7, isLocal: false, isDefinition: true, isOptimized: true, function: float (float*, float*)* @foo, variables: !4)
+!7 = !DISubroutineType(types: !8)
+!8 = !{!10, !10}
+!9 = !DIBasicType(name: "float", size: 4, align: 4, encoding: DW_ATE_float)
+!10 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !9, size: 64, align: 64)
+!11 = !DILocalVariable(tag: DW_TAG_arg_variable, name: "a", arg: 1, scope: !6, file: !3, line: 1, type: !10)
+!12 = !DIExpression(DW_OP_plus, 0)
+!13 = !DILocalVariable(tag: DW_TAG_arg_variable, name: "b", arg: 2, scope: !6, file: !3, line: 1, type: !10)
+!14 = !DIExpression(DW_OP_plus, 8)
+!15 = !DILocalVariable(tag: DW_TAG_arg_variable, name: "c", arg: 3, scope: !6, file: !3, line: 1, type: !10)
+!16 = !DIExpression(DW_OP_plus, 8, DW_OP_plus, 8)
+!17 = !DILocalVariable(tag: DW_TAG_arg_variable, name: "d", arg: 4, scope: !6, file: !3, line: 1, type: !9)
+!18 = !DIExpression(DW_OP_plus, 16, DW_OP_plus, 8, DW_OP_deref)
+!19 = !DILocation(line: 1, scope: !6)