| Message ID | ZtH9V6KLPGFxiE/G@arm.com |
|---|---|
| State | New |
| Headers | show |
| Series | gdbhooks: Handle references to vec* in VecPrinter | expand |
On 30/08/2024 18:11, Alex Coplan wrote: > Hi, > > vec.h has this method: > > template<typename T, typename A> > inline T * > vec_safe_push (vec<T, A, vl_embed> *&v, const T &obj CXX_MEM_STAT_INFO) > > where v is a reference to a pointer to vec. This matches the regex for > VecPrinter, so gdbhooks.py attempts to print it but chokes on the reference. > I see the following: > > #1 0x0000000002b84b7b in vec_safe_push<edge_def*, va_gc> (v=Traceback (most > recent call last): > File "$SRC/gcc/gcc/gdbhooks.py", line 486, in to_string > return '0x%x' % intptr(self.gdbval) > File "$SRC/gcc/gcc/gdbhooks.py", line 168, in intptr > return long(gdbval) if sys.version_info.major == 2 else int(gdbval) > gdb.error: Cannot convert value to long. > > This patch makes VecPrinter handle such references by stripping them > (dereferencing) at the top of the relevant functions. > > I thought about trying to make VecPrinter.{to_string,children} robust > against non-pointer values (i.e. actual vec structs) as the current > calls to intptr will fail on those. However, I then realised that the > current regex only matches pointer types: > > pp.add_printer_for_regex(r'vec<(\S+), (\S+), (\S+)> \*', > 'vec', > VecPrinter) > > That is somewhat at odds with the (pre-existing) code in > VecPrinter.children which appears to attempt to handle non-pointer > types. ISTM either we should drop the handling for non-pointer types > (since the regex requires a pointer) or (perhaps more usefully) relax > the regex to allow matching a plain vec<...> struct and fix the member > functions to handle those properly. > > Any thoughts on that, Dave? Is the current patch OK as an intermediate > step (manually tested by verifying both a vec*& and vec* print OK)? Gentle ping on this. > > Thanks, > Alex > > gcc/ChangeLog: > > * gdbhooks.py (strip_ref): New. Use it ... > (VecPrinter.to_string): ... here, > (VecPrinter.children): ... and here. > diff --git a/gcc/gdbhooks.py b/gcc/gdbhooks.py > index 904ee28423a..a91e5fd2a83 100644 > --- a/gcc/gdbhooks.py > +++ b/gcc/gdbhooks.py > @@ -472,6 +472,11 @@ def get_vec_kind(val): > else: > assert False, f"unexpected vec kind {kind}" > > +def strip_ref(gdbval): > + if gdbval.type.code == gdb.TYPE_CODE_REF: > + return gdbval.referenced_value () > + return gdbval > + > class VecPrinter: > # -ex "up" -ex "p bb->preds" > def __init__(self, gdbval): > @@ -483,10 +488,10 @@ class VecPrinter: > def to_string (self): > # A trivial implementation; prettyprinting the contents is done > # by gdb calling the "children" method below. > - return '0x%x' % intptr(self.gdbval) > + return '0x%x' % intptr(strip_ref(self.gdbval)) > > def children (self): > - val = self.gdbval > + val = strip_ref(self.gdbval) > if intptr(val) != 0 and get_vec_kind(val) == VEC_KIND_PTR: > val = val['m_vec'] >
On 9/23/24 4:33 AM, Alex Coplan wrote: > On 30/08/2024 18:11, Alex Coplan wrote: >> Hi, >> >> vec.h has this method: >> >> template<typename T, typename A> >> inline T * >> vec_safe_push (vec<T, A, vl_embed> *&v, const T &obj CXX_MEM_STAT_INFO) >> >> where v is a reference to a pointer to vec. This matches the regex for >> VecPrinter, so gdbhooks.py attempts to print it but chokes on the reference. >> I see the following: >> >> #1 0x0000000002b84b7b in vec_safe_push<edge_def*, va_gc> (v=Traceback (most >> recent call last): >> File "$SRC/gcc/gcc/gdbhooks.py", line 486, in to_string >> return '0x%x' % intptr(self.gdbval) >> File "$SRC/gcc/gcc/gdbhooks.py", line 168, in intptr >> return long(gdbval) if sys.version_info.major == 2 else int(gdbval) >> gdb.error: Cannot convert value to long. >> >> This patch makes VecPrinter handle such references by stripping them >> (dereferencing) at the top of the relevant functions. >> >> I thought about trying to make VecPrinter.{to_string,children} robust >> against non-pointer values (i.e. actual vec structs) as the current >> calls to intptr will fail on those. However, I then realised that the >> current regex only matches pointer types: >> >> pp.add_printer_for_regex(r'vec<(\S+), (\S+), (\S+)> \*', >> 'vec', >> VecPrinter) >> >> That is somewhat at odds with the (pre-existing) code in >> VecPrinter.children which appears to attempt to handle non-pointer >> types. ISTM either we should drop the handling for non-pointer types >> (since the regex requires a pointer) or (perhaps more usefully) relax >> the regex to allow matching a plain vec<...> struct and fix the member >> functions to handle those properly. >> >> Any thoughts on that, Dave? Is the current patch OK as an intermediate >> step (manually tested by verifying both a vec*& and vec* print OK)? > > Gentle ping on this. OK Jeff
diff --git a/gcc/gdbhooks.py b/gcc/gdbhooks.py index 904ee28423a..a91e5fd2a83 100644 --- a/gcc/gdbhooks.py +++ b/gcc/gdbhooks.py @@ -472,6 +472,11 @@ def get_vec_kind(val): else: assert False, f"unexpected vec kind {kind}" +def strip_ref(gdbval): + if gdbval.type.code == gdb.TYPE_CODE_REF: + return gdbval.referenced_value () + return gdbval + class VecPrinter: # -ex "up" -ex "p bb->preds" def __init__(self, gdbval): @@ -483,10 +488,10 @@ class VecPrinter: def to_string (self): # A trivial implementation; prettyprinting the contents is done # by gdb calling the "children" method below. - return '0x%x' % intptr(self.gdbval) + return '0x%x' % intptr(strip_ref(self.gdbval)) def children (self): - val = self.gdbval + val = strip_ref(self.gdbval) if intptr(val) != 0 and get_vec_kind(val) == VEC_KIND_PTR: val = val['m_vec']
Hi, vec.h has this method: template<typename T, typename A> inline T * vec_safe_push (vec<T, A, vl_embed> *&v, const T &obj CXX_MEM_STAT_INFO) where v is a reference to a pointer to vec. This matches the regex for VecPrinter, so gdbhooks.py attempts to print it but chokes on the reference. I see the following: #1 0x0000000002b84b7b in vec_safe_push<edge_def*, va_gc> (v=Traceback (most recent call last): File "$SRC/gcc/gcc/gdbhooks.py", line 486, in to_string return '0x%x' % intptr(self.gdbval) File "$SRC/gcc/gcc/gdbhooks.py", line 168, in intptr return long(gdbval) if sys.version_info.major == 2 else int(gdbval) gdb.error: Cannot convert value to long. This patch makes VecPrinter handle such references by stripping them (dereferencing) at the top of the relevant functions. I thought about trying to make VecPrinter.{to_string,children} robust against non-pointer values (i.e. actual vec structs) as the current calls to intptr will fail on those. However, I then realised that the current regex only matches pointer types: pp.add_printer_for_regex(r'vec<(\S+), (\S+), (\S+)> \*', 'vec', VecPrinter) That is somewhat at odds with the (pre-existing) code in VecPrinter.children which appears to attempt to handle non-pointer types. ISTM either we should drop the handling for non-pointer types (since the regex requires a pointer) or (perhaps more usefully) relax the regex to allow matching a plain vec<...> struct and fix the member functions to handle those properly. Any thoughts on that, Dave? Is the current patch OK as an intermediate step (manually tested by verifying both a vec*& and vec* print OK)? Thanks, Alex gcc/ChangeLog: * gdbhooks.py (strip_ref): New. Use it ... (VecPrinter.to_string): ... here, (VecPrinter.children): ... and here.