Commit 843390c5 authored by Adrian Prantl's avatar Adrian Prantl
Browse files

Apply proper source location to fallthrough switch cases. 

This fixes a bug in clang where, when clang sees a switch with a
fallthrough to a default like this:

static void funcA(void) {}
static void funcB(void) {}

int main(int argc, char **argv) {

switch (argc) {
    case 0:
        funcA();
        break;
    case 10:
    default:
        funcB();
        break;
}
}

It does not add a proper debug location for that switch case, such as
case 10: above.

Patch by Shubham Rastogi!

Differential Revision: https://reviews.llvm.org/D109940
parent 9ff848c5

clang/lib/CodeGen/CGStmt.cpp

+6 −0
Original line number Diff line number Diff line
@@ -1521,6 +1521,12 @@ void CodeGenFunction::EmitCaseStmt(const CaseStmt &S, 
    NextCase = dyn_cast<CaseStmt>(CurCase->getSubStmt());

  }



  // Generate a stop point for debug info if the case statement is

  // followed by a default statement. A fallthrough case before a

  // default case gets its own branch target.

  if (CurCase->getSubStmt()->getStmtClass() == Stmt::DefaultStmtClass)

    EmitStopPoint(CurCase);



  // Normal default recursion for non-cases.

  EmitStmt(CurCase->getSubStmt());

}

clang/test/CodeGen/debug-info-switch-fallthrough.c

0 → 100644
+17 −0
Original line number Diff line number Diff line 
// RUN:  %clang_cc1 -triple x86_64-apple-macosx11.0.0 -debug-info-kind=standalone -emit-llvm %s -o - | FileCheck %s

// CHECK: ], !dbg !{{[0-9]+}}

// CHECK-EMPTY:

// CHECK-NEXT: {{.+}}

// CHECK-NEXT: br {{.+}}, !dbg !{{[0-9+]}}

// CHECK-EMPTY:

// CHECK-NEXT: {{.+}}

// CHECK-NEXT: br {{.+}}, !dbg ![[LOC:[0-9]+]]

void test(int num) {

  switch (num) {

  case 0:

    break;

  case 10: // CHECK: ![[LOC]] = !DILocation(line: [[@LINE]], column:{{.+}}, scope: {{.+}})

  default:

    break;

  }

}