Move the complex address expression out of DIVariable and into an extra

argument of the llvm.dbg.declare/llvm.dbg.value intrinsics.

Previously, DIVariable was a variable-length field that has an optional
reference to a Metadata array consisting of a variable number of
complex address expressions. In the case of OpPiece expressions this is
wasting a lot of storage in IR, because when an aggregate type is, e.g.,
SROA'd into all of its n individual members, the IR will contain n copies
of the DIVariable, all alike, only differing in the complex address
reference at the end.

By making the complex address into an extra argument of the
dbg.value/dbg.declare intrinsics, all of the pieces can reference the
same variable and the complex address expressions can be uniqued across
the CU, too.
Down the road, this will allow us to move other flags, such as
"indirection" out of the DIVariable, too.

The new intrinsics look like this:
declare void @llvm.dbg.declare(metadata %storage, metadata %var, metadata %expr)
declare void @llvm.dbg.value(metadata %storage, i64 %offset, metadata %var, metadata %expr)

This patch adds a new LLVM-local tag to DIExpressions, so we can detect
and pretty-print DIExpression metadata nodes.

What this patch doesn't do:

This patch does not touch the "Indirect" field in DIVariable; but moving
that into the expression would be a natural next step.

http://reviews.llvm.org/D4919
rdar://problem/17994491

Thanks to dblaikie and dexonsmith for reviewing this patch!

Note: I accidentally committed a bogus older version of this patch previously.
llvm-svn: 218787

1 files changed, 7 insertions, 7 deletions

diff --git a/llvm/test/DebugInfo/X86/debug-info-block-captured-self.ll b/llvm/test/DebugInfo/X86/debug-info-block-captured-self.ll
index 95eda60c5cc..9587a6dc016 100644
--- a/llvm/test/DebugInfo/X86/debug-info-block-captured-self.ll
+++ b/llvm/test/DebugInfo/X86/debug-info-block-captured-self.ll
@@ -63,18 +63,18 @@
 ; ModuleID = 'llvm/tools/clang/test/CodeGenObjC/debug-info-block-captured-self.m'
 %0 = type opaque
 %struct.__block_descriptor = type { i64, i64 }
-declare void @llvm.dbg.declare(metadata, metadata) #1
+declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
 define internal void @"__24-[Main initWithContext:]_block_invoke"(i8* %.block_descriptor, i8* %obj) #0 {
   %block = bitcast i8* %.block_descriptor to <{ i8*, i32, i32, i8*, %struct.__block_descriptor*, %0* }>*, !dbg !84
   %block.captured-self = getelementptr inbounds <{ i8*, i32, i32, i8*, %struct.__block_descriptor*, %0* }>* %block, i32 0, i32 5, !dbg !84
-  call void @llvm.dbg.declare(metadata !{<{ i8*, i32, i32, i8*, %struct.__block_descriptor*, %0* }>* %block}, metadata !86), !dbg !87
+  call void @llvm.dbg.declare(metadata !{<{ i8*, i32, i32, i8*, %struct.__block_descriptor*, %0* }>* %block}, metadata !86, metadata !110), !dbg !87
   ret void, !dbg !87
 }
 
 define internal void @"__24-[Main initWithContext:]_block_invoke_2"(i8* %.block_descriptor, i8* %object) #0 {
   %block = bitcast i8* %.block_descriptor to <{ i8*, i32, i32, i8*, %struct.__block_descriptor*, %0* }>*, !dbg !103
   %block.captured-self = getelementptr inbounds <{ i8*, i32, i32, i8*, %struct.__block_descriptor*, %0* }>* %block, i32 0, i32 5, !dbg !103
-  call void @llvm.dbg.declare(metadata !{<{ i8*, i32, i32, i8*, %struct.__block_descriptor*, %0* }>* %block}, metadata !105), !dbg !106
+  call void @llvm.dbg.declare(metadata !{<{ i8*, i32, i32, i8*, %struct.__block_descriptor*, %0* }>* %block}, metadata !105, metadata !109), !dbg !106
   ret void, !dbg !106
 }
 
@@ -101,12 +101,12 @@ define internal void @"__24-[Main initWithContext:]_block_invoke_2"(i8* %.block_
 !41 = metadata !{i32 786447, null, null, metadata !"", i32 0, i64 64, i64 64, i64 0, i32 0, null} ; [ DW_TAG_pointer_type ] [line 0, size 64, align 64, offset 0] [from ]
 !42 = metadata !{i32 786478, metadata !1, metadata !1, metadata !"__24-[Main initWithContext:]_block_invoke_2", metadata !"__24-[Main initWithContext:]_block_invoke_2", metadata !"", i32 35, metadata !39, i1 true, i1 true, i32 0, i32 0, null, i32 256, i1 false, void (i8*, i8*)* @"__24-[Main initWithContext:]_block_invoke_2", null, null, metadata !15, i32 35} ; [ DW_TAG_subprogram ] [line 35] [local] [def] [__24-[Main initWithContext:]_block_invoke_2]
 !84 = metadata !{i32 33, i32 0, metadata !38, null}
-!86 = metadata !{i32 786688, metadata !38, metadata !"self", metadata !1, i32 41, metadata !34, i32 0, i32 0, metadata !110} ; [ DW_TAG_auto_variable ] [self] [line 41]
+!86 = metadata !{i32 786688, metadata !38, metadata !"self", metadata !1, i32 41, metadata !34, i32 0, i32 0} ;; [ DW_TAG_auto_variable ] [self] [line 41]
 !87 = metadata !{i32 41, i32 0, metadata !38, null}
 !103 = metadata !{i32 35, i32 0, metadata !42, null}
-!105 = metadata !{i32 786688, metadata !42, metadata !"self", metadata !1, i32 40, metadata !34, i32 0, i32 0, metadata !109} ; [ DW_TAG_auto_variable ] [self] [line 40]
+!105 = metadata !{i32 786688, metadata !42, metadata !"self", metadata !1, i32 40, metadata !34, i32 0, i32 0} ;; [ DW_TAG_auto_variable ] [self] [line 40]
 !106 = metadata !{i32 40, i32 0, metadata !42, null}
 !107 = metadata !{metadata !"llvm/tools/clang/test/CodeGenObjC/debug-info-block-captured-self.m", metadata !""}
 !108 = metadata !{i32 1, metadata !"Debug Info Version", i32 1}
-!109 = metadata !{i64 1, i64 32}
-!110 = metadata !{i64 1, i64 32}
+!109 = metadata !{i32 786690, i64 34, i64 32} ; [DW_OP_plus 32]
+!110 = metadata !{i32 786690, i64 34, i64 32} ; [DW_OP_plus 32]