[LLVMbugs] [Bug 17491] New: Incorrect line number for 'return' in clang

[bugzilla-daemon at llvm.org]

http://llvm.org/bugs/show_bug.cgi?id=17491

            Bug ID: 17491
           Summary: Incorrect line number for 'return' in clang
           Product: clang
           Version: trunk
          Hardware: Macintosh
                OS: MacOS X
            Status: NEW
          Severity: normal
          Priority: P
         Component: Frontend
          Assignee: unassignedclangbugs at nondot.org
          Reporter: olga.a.chupina at gmail.com
                CC: llvmbugs at cs.uiuc.edu
    Classification: Unclassified

Clang produces bad line number for 'return' when variable-length array presents
in the test.

Example: 
--- test.c ---
#include <stdio.h>

int main(int argc) {
    char str[argc];
    scanf("%s", str);
    return str[0];
}
--------------
Compilation line: clang -g -S -emit-llvm -o test.bc test.c

test.bc:

; Function Attrs: nounwind ssp uwtable
define i32 @main(i32 %argc) #0 {
entry:
  %retval = alloca i32, align 4
  %argc.addr = alloca i32, align 4
  %saved_stack = alloca i8*
  %cleanup.dest.slot = alloca i32
  store i32 0, i32* %retval
  store i32 %argc, i32* %argc.addr, align 4
  call void @llvm.dbg.declare(metadata !{i32* %argc.addr}, metadata !10), !dbg
!11
  %0 = load i32* %argc.addr, align 4, !dbg !12
  %1 = zext i32 %0 to i64, !dbg !12
  %2 = call i8* @llvm.stacksave(), !dbg !12
  store i8* %2, i8** %saved_stack, !dbg !12
  %vla = alloca i8, i64 %1, align 16, !dbg !12
  call void @llvm.dbg.declare(metadata !{i8* %vla}, metadata !13), !dbg !12
  %call = call i32 (i8*, ...)* @scanf(i8* getelementptr inbounds ([3 x i8]*
@.str, i32 0, i32 0), i8* %vla), !dbg !18
  %arrayidx = getelementptr inbounds i8* %vla, i64 0, !dbg !19
  %3 = load i8* %arrayidx, align 1, !dbg !19
  %conv = sext i8 %3 to i32, !dbg !19
  store i32 %conv, i32* %retval, !dbg !19
  store i32 1, i32* %cleanup.dest.slot
  %4 = load i8** %saved_stack, !dbg !20
  call void @llvm.stackrestore(i8* %4), !dbg !20
  %5 = load i32* %retval, !dbg !20
  ret i32 %5, !dbg !20
}

!llvm.dbg.cu = !{!0}  
!llvm.module.flags = !{!9}

!0 = metadata !{i32 786449, metadata !1, i32 12, metadata !"clang version 3.4
(trunk 191815)", i1 false, metadata !"", i32 0, metadata !2, metadata !2,
metadata !3, metadata !2, metadata !2, metadata !""} ; [ DW_TAG_compile_unit ]
[test.c] [DW_LANG_C99]
...
!18 = metadata !{i32 5, i32 0, metadata !4, null}
!19 = metadata !{i32 6, i32 0, metadata !4, null}
!20 = metadata !{i32 7, i32 0, metadata !4, null}

'Return' should be at line 6. 


Olga Chupina
---
Software Engineer
Intel Compiler Team
Intel Corp.

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