Hello All:
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. Bootstrapped and regtested on powerpc64-linux-gnu. Thanks & Regards Ajit rs6000: Stackoverflow in optimized code on PPC (PR100799) 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. 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 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. * function.h: Add new field hidden_string_length and actual_parm_length in function structure. --- gcc/config/rs6000/rs6000-call.cc | 11 ++++++++++- gcc/function.cc | 26 ++++++++++++++++++++++++++ gcc/function.h | 10 ++++++++++ 3 files changed, 46 insertions(+), 1 deletion(-) diff --git a/gcc/config/rs6000/rs6000-call.cc b/gcc/config/rs6000/rs6000-call.cc index 1f8f93a2ee7..8e6e3de6804 100644 --- 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