cross-project-tests/debuginfo-tests/dexter-tests/memvars/loop.c

   1 // XFAIL: *
   2 //// Suboptimal coverage, see below.
   3
   4 // REQUIRES: lldb
   5 // UNSUPPORTED: system-windows
   6 // RUN: %clang -std=gnu11 -O3 -glldb %s -o %t
   7 // RUN: %dexter --fail-lt 1.0 -w --debugger lldb --binary %t -- %s
   8
   9 //// Check that escaped local 'param' in function 'fun' has sensible debug info
  10 //// after the escaping function 'use' gets arg promotion (int* -> int). Currently
  11 //// we lose track of param after the loop header.
  12
  13 int g = 0;
  14 //// A no-inline, read-only function with internal linkage is a good candidate
  15 //// for arg promotion.
  16 __attribute__((__noinline__))
  17 static void use(const int* p) {
  18   //// Promoted args would be a good candidate for an DW_OP_implicit_pointer.
  19   //// This desirable behaviour is checked for in the test implicit-ptr.c.
  20   g = *p;
  21 }
  22
  23 __attribute__((__noinline__))
  24 void do_thing(int x) {
  25   g *= x;
  26 }
  27
  28 __attribute__((__noinline__))
  29 int fun(int param) {
  30   do_thing(0);                        // DexLabel('s2')
  31   for (int i = 0; i < param; ++i) {
  32     use(&param);
  33   }
  34
  35   //// x86 loop body looks like this, with param in ebx:
  36   //// 4004b0: mov    edi,ebx
  37   //// 4004b2: call   4004d0 <_ZL3usePKi>
  38   //// 4004b7: add    ebp,0xffffffff
  39   //// 4004ba: jne    4004b0 <_Z3funi+0x20>
  40
  41   //// But we lose track of param's location before the loop:
  42   //// DW_TAG_formal_parameter
  43   //// DW_AT_location   (0x00000039:
  44   ////    [0x0000000000400490, 0x0000000000400495): DW_OP_reg5 RDI
  45   ////    [0x0000000000400495, 0x00000000004004a2): DW_OP_reg3 RBX)
  46   //// DW_AT_name       ("param")
  47
  48   return g;                           // DexLabel('s3')
  49 }
  50
  51 int main() {
  52   return fun(5);
  53 }
  54
  55 // DexExpectWatchValue('*p', 5, 5, 5, 5, 5, on_line=ref('s1'))
  56 // DexExpectWatchValue('param', 5, from_line=ref('s2'), to_line=ref('s3'))