On Fri, Mar 22, 2024 at 01:00:21PM +0530, Ajit Agarwal wrote: > When using FlexiBLAS with OpenBLAS we noticed corruption of > the parameters passed to OpenBLAS functions. FlexiBLAS > basically provides a BLAS interface where each function > is a stub that forwards the arguments to a real BLAS lib, > like OpenBLAS. > > Fixes the corruption of caller frame checking number of > arguments is less than equal to GP_ARG_NUM_REG (8) > excluding hidden unused DECLS.
Thanks for working on this. > 2024-03-22 Ajit Kumar Agarwal <aagar...@linux.ibm.com> > > gcc/ChangeLog: > > PR rtk-optimization/100799 > * config/rs600/rs600-calls.cc (rs6000_function_arg): Don't These 2 lines are 8 space indented rather than tab. > generate parameter save area if number of arguments passed > less than equal to GP_ARG_NUM_REG (8) excluding hidden > paramter. > * function.cc (assign_parms_initialize_all): Check for hidden > parameter in fortran code and set the flag hidden_string_length > and actual paramter passed excluding hidden unused DECLS. s/paramter/parameter/ > * function.h: Add new field hidden_string_length and > actual_parm_length in function structure. Why do you need to change generic code for something that will only be used by a single target? I mean, why don't you add the extra members in rs6000.h (struct rs6000_args) and initialize them in rs6000-call.cc (init_cumulative_args) - the function.cc function you've modified is the only one which uses INIT_CUMULATIVE_INCOMING_ARGS and in that case init_cumulative_args is called with incoming == true, so move the stuff from function.cc there. > --- a/gcc/config/rs6000/rs6000-call.cc > +++ b/gcc/config/rs6000/rs6000-call.cc > @@ -1857,7 +1857,16 @@ rs6000_function_arg (cumulative_args_t cum_v, const > function_arg_info &arg) > > return rs6000_finish_function_arg (mode, rvec, k); > } > - else if (align_words < GP_ARG_NUM_REG) > + /* Workaround buggy C/C++ wrappers around Fortran routines with > + character(len=constant) arguments if the hidden string length arguments > + are passed on the stack; if the callers forget to pass those arguments, > + attempting to tail call in such routines leads to stack corruption. > + Avoid return stack space for parameters <= 8 excluding hidden string > + length argument is passed (partially or fully) on the stack in the > + caller and the callee needs to pass any arguments on the stack. */ > + else if (align_words < GP_ARG_NUM_REG > + || (cfun->hidden_string_length > + && cfun->actual_parm_length <= GP_ARG_NUM_REG)) > { > if (TARGET_32BIT && TARGET_POWERPC64) > return rs6000_mixed_function_arg (mode, type, align_words); > diff --git a/gcc/function.cc b/gcc/function.cc > index 3cef6c17bce..1318564b466 100644 > --- a/gcc/function.cc > +++ b/gcc/function.cc > @@ -2326,6 +2326,32 @@ assign_parms_initialize_all (struct > assign_parm_data_all *all) > #endif > all->args_so_far = pack_cumulative_args (&all->args_so_far_v); > > + unsigned int num_args = 0; > + unsigned int hidden_length = 0; > + > + /* Workaround buggy C/C++ wrappers around Fortran routines with > + character(len=constant) arguments if the hidden string length arguments > + are passed on the stack; if the callers forget to pass those arguments, > + attempting to tail call in such routines leads to stack corruption. > + Avoid return stack space for parameters <= 8 excluding hidden string > + length argument is passed (partially or fully) on the stack in the > + caller and the callee needs to pass any arguments on the stack. */ > + for (tree arg = DECL_ARGUMENTS (current_function_decl); > + arg; arg = DECL_CHAIN (arg)) > + { > + num_args++; > + if (DECL_HIDDEN_STRING_LENGTH (arg)) > + { > + tree parmdef = ssa_default_def (cfun, arg); > + if (parmdef == NULL || has_zero_uses (parmdef)) > + { > + cfun->hidden_string_length = 1; > + hidden_length++; > + } > + } > + } > + > + cfun->actual_parm_length = num_args - hidden_length; > #ifdef INCOMING_REG_PARM_STACK_SPACE > all->reg_parm_stack_space > = INCOMING_REG_PARM_STACK_SPACE (current_function_decl); > diff --git a/gcc/function.h b/gcc/function.h > index 19e15bd63b0..5984f0007c2 100644 > --- a/gcc/function.h > +++ b/gcc/function.h > @@ -346,6 +346,11 @@ struct GTY(()) function { > /* Last assigned dependence info clique. */ > unsigned short last_clique; > > + /* Actual parameter length ignoring hidden paramter. > + This is done to C++ wrapper calling fortran module > + which has hidden parameter that are not used. */ > + unsigned int actual_parm_length; > + > /* Collected bit flags. */ > > /* Number of units of general registers that need saving in stdarg > @@ -442,6 +447,11 @@ struct GTY(()) function { > /* Set for artificial function created for [[assume (cond)]]. > These should be GIMPLE optimized, but not expanded to RTL. */ > unsigned int assume_function : 1; > + > + /* Hidden parameters while calling C++ wrapper to fortran > + module. Set if there is hidden parameter in fortran > + module while called C++ wrapper. */ > + unsigned int hidden_string_length : 1; > }; > > /* Add the decl D to the local_decls list of FUN. */ > -- > 2.39.3 Jakub