| Message ID | 1443891054-24079-1-git-send-email-compnerd@compnerd.org |
|---|---|
| State | New |
| Headers | show |
Saleem Abdulrasool <compnerd@compnerd.org> writes: > For ARM EHABI _Unwind_{G,S}setIP are macros rather than proper functions as they > are extensions to the EHABI specification (though they are part of the Level 1 > interface). Quote the macro parameters, as otherwise, a complex parameter may > be ambiguously mis-expanded. > --- > libgcc/config/arm/unwind-arm.h | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/libgcc/config/arm/unwind-arm.h b/libgcc/config/arm/unwind-arm.h > index f1f789c..3821c08 100644 > --- a/libgcc/config/arm/unwind-arm.h > +++ b/libgcc/config/arm/unwind-arm.h > @@ -74,10 +74,10 @@ extern "C" { > } > /* Return the address of the instruction, not the actual IP value. */ > #define _Unwind_GetIP(context) \ > - (_Unwind_GetGR (context, 15) & ~(_Unwind_Word)1) > + (_Unwind_GetGR ((context), 15) & ~(_Unwind_Word)1) How can that get mis-expanded (other than cheating with a macro that expands to a comma)? Andreas.
Saleem Abdulrasool <compnerd@compnerd.org> writes: > On Saturday, October 3, 2015, Andreas Schwab <schwab@linux-m68k.org> wrote: > >> Saleem Abdulrasool <compnerd@compnerd.org <javascript:;>> writes: >> >> > For ARM EHABI _Unwind_{G,S}setIP are macros rather than proper functions >> as they >> > are extensions to the EHABI specification (though they are part of the >> Level 1 >> > interface). Quote the macro parameters, as otherwise, a complex >> parameter may >> > be ambiguously mis-expanded. >> > --- >> > libgcc/config/arm/unwind-arm.h | 4 ++-- >> > 1 file changed, 2 insertions(+), 2 deletions(-) >> > >> > diff --git a/libgcc/config/arm/unwind-arm.h >> b/libgcc/config/arm/unwind-arm.h >> > index f1f789c..3821c08 100644 >> > --- a/libgcc/config/arm/unwind-arm.h >> > +++ b/libgcc/config/arm/unwind-arm.h >> > @@ -74,10 +74,10 @@ extern "C" { >> > } >> > /* Return the address of the instruction, not the actual IP value. */ >> > #define _Unwind_GetIP(context) \ >> > - (_Unwind_GetGR (context, 15) & ~(_Unwind_Word)1) >> > + (_Unwind_GetGR ((context), 15) & ~(_Unwind_Word)1) >> >> How can that get mis-expanded (other than cheating with a macro that >> expands to a comma)? >> > > Poor choice of words on my part. It won't mis-expand, it may expand into > an "ambiguous" statement (which will be diagnosed with a warning) if the > argument is an expression in the sense of: > > a + b | 1 That cannot happen here, unless the caller already passes such an expression. Andreas.
diff --git a/libgcc/config/arm/unwind-arm.h b/libgcc/config/arm/unwind-arm.h index f1f789c..3821c08 100644 --- a/libgcc/config/arm/unwind-arm.h +++ b/libgcc/config/arm/unwind-arm.h @@ -74,10 +74,10 @@ extern "C" { } /* Return the address of the instruction, not the actual IP value. */ #define _Unwind_GetIP(context) \ - (_Unwind_GetGR (context, 15) & ~(_Unwind_Word)1) + (_Unwind_GetGR ((context), 15) & ~(_Unwind_Word)1) #define _Unwind_SetIP(context, val) \ - _Unwind_SetGR (context, 15, val | (_Unwind_GetGR (context, 15) & 1)) + _Unwind_SetGR ((context), 15, (val) | (_Unwind_GetGR ((context), 15) & 1)) #ifdef __cplusplus } /* extern "C" */
For ARM EHABI _Unwind_{G,S}setIP are macros rather than proper functions as they are extensions to the EHABI specification (though they are part of the Level 1 interface). Quote the macro parameters, as otherwise, a complex parameter may be ambiguously mis-expanded. --- libgcc/config/arm/unwind-arm.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)