llvm/test/DebugInfo/Generic/debug-info-always-inline.ll

; RUN: opt < %s -always-inline -S | FileCheck %s
;
; Generated from the following C++ source with:
; clang -cc1 -disable-llvm-optzns -emit-llvm -g -stack-protector 2 test.cpp
;
; /* BEGIN SOURCE */
; int __attribute__((always_inline)) foo()
; {
;    int arr[10];
;    arr[0] = 5;
;    int sum = 4;
;    return sum;
; }
; 
; extern void bar();
; 
; int main()
; {
;   bar();
;   int i = foo();
;   return i;
; }
; /* END SOURCE */

; The patch that includes this test case, is addressing the following issue:
; 
; When functions are inlined, instructions without debug information 
; are attributed with the call site's DebugLoc. After inlining, inlined static
; allocas are moved to the caller's entry block, adjacent to the caller's original
; static alloca instructions. By retaining the call site's DebugLoc, these instructions
; may cause instructions that are subsequently inserted at the entry block to pick
; up the same DebugLoc.
;
; In the offending case stack protection inserts an instruction at the caller's
; entry block, which inadvertently picks up the inlined call's DebugLoc, because
; the entry block's first instruction is the recently moved inlined alloca instruction. 
;
; The stack protection instruction then becomes part of the function prologue, with the
; result that the line number that is associated with the stack protection instruction
; is deemed to be the end of the function prologue. Since this line number is the
; call site's line number, setting a breakpoint at the function in the debugger
; will make the user stop at the line of the inlined call.

; Note that without the stack protection instruction this effect would not occur
; because the allocas all get collapsed into a single instruction that reserves
; stack space and have no further influence on the prologue's line number information.


; The selected solution is to not attribute static allocas with the call site's
; DebugLoc. 

; At some point in the future, it may be desirable to describe the inlining 
; in the alloca instructions, but then the code that handles prologues must
; be able to handle this correctly, including the late insertion of instructions
; into it.

; In this context it is also important to distingush between functions
; with the "nodebug" attribute and those without it. Alloca instructions from
; nodebug functions should continue to have no DebugLoc, whereas those from
; non-nodebug functions (i.e. functions with debug information) may want to
; have their DebugLocs augmented with inlining information.


; Make sure that after inlining the call to foo() the alloca instructions for
; arr.i and sum.i do not retain debug information.

; CHECK: %arr.i = alloca [10 x i32], align {{[0-9]*$}}
; CHECK: %sum.i = alloca i32, align {{[0-9]*$}}


; ModuleID = 'test.cpp'
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

; Function Attrs: alwaysinline nounwind sspstrong
define i32 @_Z3foov() #0 {
entry:
  %arr = alloca [10 x i32], align 16
  %sum = alloca i32, align 4
  call void @llvm.dbg.declare(metadata [10 x i32]* %arr, metadata !14), !dbg !18
  %arrayidx = getelementptr inbounds [10 x i32], [10 x i32]* %arr, i32 0, i64 0, !dbg !19
  store i32 5, i32* %arrayidx, align 4, !dbg !19
  call void @llvm.dbg.declare(metadata i32* %sum, metadata !20), !dbg !21
  store i32 4, i32* %sum, align 4, !dbg !21
  %0 = load i32, i32* %sum, align 4, !dbg !22
  ret i32 %0, !dbg !22
}

; Function Attrs: nounwind readnone
declare void @llvm.dbg.declare(metadata, metadata) #1

; Function Attrs: nounwind sspstrong
define i32 @main() #2 {
entry:
  %retval = alloca i32, align 4
  %i = alloca i32, align 4
  store i32 0, i32* %retval
  call void @_Z3barv(), !dbg !23
  call void @llvm.dbg.declare(metadata i32* %i, metadata !24), !dbg !25
  %call = call i32 @_Z3foov(), !dbg !25
  store i32 %call, i32* %i, align 4, !dbg !25
  %0 = load i32, i32* %i, align 4, !dbg !26
  ret i32 %0, !dbg !26
}

declare void @_Z3barv() #3

attributes #0 = { alwaysinline nounwind sspstrong "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-realign-stack" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
attributes #1 = { nounwind readnone }
attributes #2 = { nounwind sspstrong "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-realign-stack" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
attributes #3 = { "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-realign-stack" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }

!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!11, !12}
!llvm.ident = !{!13}

!0 = !{i32 786449, !1, i32 4, !"clang version 3.6.0 (217844)", i1 false, !"", i32 0, !2, !2, !3, !2, !2, !"", i32 1} ; [ DW_TAG_compile_unit ] [/home/user/test/<stdin>] [DW_LANG_C_plus_plus]
!1 = !{!"<stdin>", !"/home/user/test"}
!2 = !{}
!3 = !{!4, !10}
!4 = !{i32 786478, !5, !6, !"foo", !"foo", !"_Z3foov", i32 1, !7, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 false, i32 ()* @_Z3foov, null, null, !2, i32 2} ; [ DW_TAG_subprogram ] [line 1] [def] [scope 2] [foo]
!5 = !{!"test.cpp", !"/home/user/test"}
!6 = !{i32 786473, !5}          ; [ DW_TAG_file_type ] [/home/user/test/test.cpp]
!7 = !{i32 786453, i32 0, null, !"", i32 0, i64 0, i64 0, i64 0, i32 0, null, !8, i32 0, null, null, null} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
!8 = !{!9}
!9 = !{i32 786468, null, null, !"int", i32 0, i64 32, i64 32, i64 0, i32 0, i32 5} ; [ DW_TAG_base_type ] [int] [line 0, size 32, align 32, offset 0, enc DW_ATE_signed]
!10 = !{i32 786478, !5, !6, !"main", !"main", !"", i32 11, !7, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 false, i32 ()* @main, null, null, !2, i32 12} ; [ DW_TAG_subprogram ] [line 11] [def] [scope 12] [main]
!11 = !{i32 2, !"Dwarf Version", i32 4}
!12 = !{i32 2, !"Debug Info Version", i32 1}
!13 = !{!"clang version 3.6.0 (217844)"}
!14 = !{i32 786688, !4, !"arr", !6, i32 3, !15, i32 0, i32 0} ; [ DW_TAG_auto_variable ] [arr] [line 3]
!15 = !{i32 786433, null, null, !"", i32 0, i64 320, i64 32, i32 0, i32 0, !9, !16, i32 0, null, null, null} ; [ DW_TAG_array_type ] [line 0, size 320, align 32, offset 0] [from int]
!16 = !{!17}
!17 = !{i32 786465, i64 0, i64 10}       ; [ DW_TAG_subrange_type ] [0, 9]
!18 = !DILocation(line: 3, scope: !4)
!19 = !DILocation(line: 4, scope: !4)
!20 = !{i32 786688, !4, !"sum", !6, i32 5, !9, i32 0, i32 0} ; [ DW_TAG_auto_variable ] [sum] [line 5]
!21 = !DILocation(line: 5, scope: !4)
!22 = !DILocation(line: 6, scope: !4)
!23 = !DILocation(line: 13, scope: !10)
!24 = !{i32 786688, !10, !"i", !6, i32 14, !9, i32 0, i32 0} ; [ DW_TAG_auto_variable ] [i] [line 14]
!25 = !DILocation(line: 14, scope: !10)
!26 = !DILocation(line: 15, scope: !10)