debug locations that extend beyond their enclosing scope

Anyone seen these/have interest in fixing them - maybe even making the DWARF verifier diagnose them?


$ cat scope.cpp
attribute((const)) int f1(int);

attribute((always_inline)) int f2(int a) {
return f1(a);

int func(bool b, int a){
if (b)
return f2(a);
return f2(a);
$ clang+±tot scope.cpp -g -O3 -c && llvm-dwarfdump-tot scope.o

DW_AT_abstract_origin (0x00000047 “_Z2f2i”)
DW_AT_low_pc (0x0000000000000012)
DW_AT_high_pc (0x0000000000000017)

DW_AT_location (0x0000007c
[0x0000000000000010, 0x0000000000000012): DW_OP_reg4 RSI
[0x0000000000000012, 0x0000000000000017): DW_OP_reg5 RDI)

That first part of the location description looks like it’s completely unnecessary/unusable & once that’s removed, then the second location covers the entire range of the enclosing scope and could use a direct location description rather than indirecting through debug_loc/loclists.

It looks like in this case not only extended range is the problem.
That line :
[0x0000000000000012, 0x0000000000000017): DW_OP_reg5 RDI)
looks wrong since "a" is in the %rsi in fact.

27.09.2019 21:13, David Blaikie пишет: