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llvm-mirror/test/DebugInfo/Generic/simplifycfg_sink_last_inst.ll
Shiva Chen a2029fa58e [DebugInfo] Add DILabel metadata and intrinsic llvm.dbg.label.
In order to set breakpoints on labels and list source code around
labels, we need collect debug information for labels, i.e., label
name, the function label belong, line number in the file, and the
address label located. In order to keep these information in LLVM
IR and to allow backend to generate debug information correctly.
We create a new kind of metadata for labels, DILabel. The format
of DILabel is

!DILabel(scope: !1, name: "foo", file: !2, line: 3)

We hope to keep debug information as much as possible even the
code is optimized. So, we create a new kind of intrinsic for label
metadata to avoid the metadata is eliminated with basic block.
The intrinsic will keep existing if we keep it from optimized out.
The format of the intrinsic is

llvm.dbg.label(metadata !1)

It has only one argument, that is the DILabel metadata. The
intrinsic will follow the label immediately. Backend could get the
label metadata through the intrinsic's parameter.

We also create DIBuilder API for labels to be used by Frontend.
Frontend could use createLabel() to allocate DILabel objects, and use
insertLabel() to insert llvm.dbg.label intrinsic in LLVM IR.

Differential Revision: https://reviews.llvm.org/D45024

Patch by Hsiangkai Wang.

llvm-svn: 331841
2018-05-09 02:40:45 +00:00

113 lines
4.0 KiB
LLVM

; RUN: opt -simplifycfg -sink-common-insts -S < %s | FileCheck %s
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
; Simplify CFG will try to sink the last instruction in a series of basic
; blocks, creating a "common" instruction in the successor block. If the
; debug locations of the commoned instructions have different file/line
; numbers the debug location of the common instruction should be a merged
; location.
; Generated from source:
; extern int foo(void);
; extern int bar(void);
;
; int test(int a, int b) {
; if(a)
; b -= foo();
; else
; b -= bar();
; return b;
; }
; CHECK: define i32 @test
; CHECK-LABEL: if.end:
; CHECK: %[[PHI:.*]] = phi i32 [ %call1, %if.else ], [ %call, %if.then ]
; CHECK: sub nsw i32 %b, %[[PHI]], !dbg [[testMergedLoc:![0-9]+]]
; CHECK: ret i32
define i32 @test(i32 %a, i32 %b) !dbg !6 {
entry:
%tobool = icmp ne i32 %a, 0, !dbg !8
br i1 %tobool, label %if.then, label %if.else, !dbg !8
if.then: ; preds = %entry
%call = call i32 @foo(), !dbg !9
%sub = sub nsw i32 %b, %call, !dbg !10
br label %if.end, !dbg !11
if.else: ; preds = %entry
%call1 = call i32 @bar(), !dbg !12
%sub2 = sub nsw i32 %b, %call1, !dbg !13
br label %if.end
if.end: ; preds = %if.else, %if.then
%b.addr.0 = phi i32 [ %sub, %if.then ], [ %sub2, %if.else ]
ret i32 %b.addr.0, !dbg !14
}
; When the commoned instructions have the same debug location, this location
; should be used as the location of the common instruction.
; Generated from source (with -mllvm -no-discriminators and -gno-column-info):
; int test2(int a, int b) {
; if(a) b -= foo(); else b -= bar();
; return b;
; }
; CHECK: define i32 @test2
; CHECK-LABEL: if.end:
; CHECK: %[[PHI:.*]] = phi i32 [ %call1, %if.else ], [ %call, %if.then ]
; CHECK: sub nsw i32 %b, %[[PHI]], !dbg [[test2Loc:![0-9]+]]
; CHECK: ret i32
define i32 @test2(i32 %a, i32 %b) !dbg !15 {
entry:
%tobool = icmp ne i32 %a, 0, !dbg !16
br i1 %tobool, label %if.then, label %if.else, !dbg !16
if.then: ; preds = %entry
%call = call i32 @foo(), !dbg !16
%sub = sub nsw i32 %b, %call, !dbg !16
br label %if.end, !dbg !16
if.else: ; preds = %entry
%call1 = call i32 @bar(), !dbg !16
%sub2 = sub nsw i32 %b, %call1, !dbg !16
br label %if.end
if.end: ; preds = %if.else, %if.then
%b.addr.0 = phi i32 [ %sub, %if.then ], [ %sub2, %if.else ]
ret i32 %b.addr.0, !dbg !17
}
; CHECK: [[testMergedLoc]] = !DILocation(line: 0
; CHECK: [[test2Loc]] = !DILocation(line: 17
declare i32 @foo()
declare i32 @bar()
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!3, !4}
!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "", isOptimized: false, runtimeVersion: 0, emissionKind: LineTablesOnly, enums: !2)
!1 = !DIFile(filename: "test.c", directory: "")
!2 = !{}
!3 = !{i32 2, !"Dwarf Version", i32 4}
!4 = !{i32 2, !"Debug Info Version", i32 3}
!6 = distinct !DISubprogram(name: "test", scope: !1, file: !1, line: 8, type: !7, isLocal: false, isDefinition: true, scopeLine: 8, flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !2)
!7 = !DISubroutineType(types: !2)
!8 = !DILocation(line: 9, column: 6, scope: !6)
!9 = !DILocation(line: 10, column: 10, scope: !6)
!10 = !DILocation(line: 10, column: 7, scope: !6)
!11 = !DILocation(line: 10, column: 5, scope: !6)
!12 = !DILocation(line: 12, column: 10, scope: !6)
!13 = !DILocation(line: 12, column: 7, scope: !6)
!14 = !DILocation(line: 13, column: 3, scope: !6)
!15 = distinct !DISubprogram(name: "test2", scope: !1, file: !1, line: 16, type: !7, isLocal: false, isDefinition: true, scopeLine: 16, flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !2)
!16 = !DILocation(line: 17, scope: !15)
!17 = !DILocation(line: 18, scope: !15)