Add new debug kind LocTrackingOnly.

Summary:
This new debug emission kind supports emitting line location
information in all instructions, but stops code generation
from emitting debug info to the final output.

This mode is useful when the backend wants to track source
locations during code generation, but it does not want to
produce debug info. This is currently used by optimization
remarks (-pass-remarks, -pass-remarks-missed and
-pass-remarks-analysis).

To prevent debug info emission, DIBuilder never inserts the
annotation 'llvm.dbg.cu' when LocTrackingOnly is enabled.

Reviewers: echristo, dblaikie

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D4234

llvm-svn: 211609

1 files changed, 7 insertions, 2 deletions

diff --git a/llvm/test/Transforms/LoopVectorize/X86/vectorization-remarks.ll b/llvm/test/Transforms/LoopVectorize/X86/vectorization-remarks.ll
index 685d034f219..f1641762fdc 100644
--- a/llvm/test/Transforms/LoopVectorize/X86/vectorization-remarks.ll
+++ b/llvm/test/Transforms/LoopVectorize/X86/vectorization-remarks.ll
@@ -1,6 +1,13 @@
 ; RUN: opt < %s -loop-vectorize -mtriple=x86_64-unknown-linux -S -pass-remarks='loop-vectorize' 2>&1 | FileCheck -check-prefix=VECTORIZED %s
 ; RUN: opt < %s -loop-vectorize -force-vector-width=1 -force-vector-unroll=4 -mtriple=x86_64-unknown-linux -S -pass-remarks='.*vectorize.*' 2>&1 | FileCheck -check-prefix=UNROLLED %s
 
+; This code has all the !dbg annotations needed to track source line information,
+; but is missing the llvm.dbg.cu annotation. This prevents code generation from
+; emitting debug info in the final output.
+; RUN: llc -mtriple x86_64-pc-linux-gnu %s -o - | FileCheck -check-prefix=DEBUG-OUTPUT %s
+; DEBUG-OUTPUT-NOT: .loc
+; DEBUG-OUTPUT-NOT: {{.*}}.debug_info
+
 ; VECTORIZED: remark: {{.*}}.c:17:8: vectorized loop (vectorization factor: 4, unrolling interleave factor: 1)
 ; UNROLLED: remark: {{.*}}.c:17:8: unrolled with interleaving factor 4 (vectorization not beneficial)
 
@@ -37,11 +44,9 @@ for.end:                                          ; preds = %for.body
 
 declare void @ibar(i32*) #1
 
-!llvm.dbg.cu = !{!0}
 !llvm.module.flags = !{!7, !8}
 !llvm.ident = !{!9}
 
-!0 = metadata !{i32 786449, metadata !1, i32 12, metadata !"clang version 3.5.0 ", i1 true, metadata !"", i32 0, metadata !2, metadata !2, metadata !3, metadata !2, metadata !2, metadata !"", i32 2} ; [ DW_TAG_compile_unit ] [./vectorization-remarks.c] [DW_LANG_C99]
 !1 = metadata !{metadata !"vectorization-remarks.c", metadata !"."}
 !2 = metadata !{}
 !3 = metadata !{metadata !4}