Hello Jakub: 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/rs6000/rs6000-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 parameter. (init_cumulative_args): Check for hidden parameter in fortran routine and set the flag hidden_string_length and actual parameter passed excluding hidden unused DECLS. * config/rs6000/rs6000.h (rs6000_args): Add new field hidden_string_length and actual_parm_length. --- gcc/config/rs6000/rs6000-call.cc | 40 ++++++++++++++++++++++++++++++-- gcc/config/rs6000/rs6000.h | 8 +++++++ 2 files changed, 46 insertions(+), 2 deletions(-) diff --git a/gcc/config/rs6000/rs6000-call.cc b/gcc/config/rs6000/rs6000-call.cc index 1f8f93a2ee7..2620ce16943 100644 --- a/gcc/config/rs6000/rs6000-call.cc +++ b/gcc/config/rs6000/rs6000-call.cc @@ -64,7 +64,7 @@ #include "ppc-auxv.h" #include "targhooks.h" #include "opts.h" - +#include "tree-dfa.h" #include "rs6000-internal.h" #ifndef TARGET_PROFILE_KERNEL @@ -584,6 +584,33 @@ init_cumulative_args (CUMULATIVE_ARGS *cum, tree fntype, if (incoming || cum->prototype) cum->nargs_prototype = n_named_args; + /* 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. */ + unsigned int num_args = 0; + unsigned int hidden_length = 0; + + 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)) + { + cum->hidden_string_length = 1; + hidden_length++; + } + } + } + + cum->actual_parm_length = num_args - hidden_length; + /* Check for a longcall attribute. */ if ((!fntype && rs6000_default_long_calls) || (fntype @@ -1857,7 +1884,16 @@ 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 + || (cum->hidden_string_length + && cum->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/config/rs6000/rs6000.h b/gcc/config/rs6000/rs6000.h index 68bc45d65ba..a1d3ed00b14 100644 --- a/gcc/config/rs6000/rs6000.h +++ b/gcc/config/rs6000/rs6000.h @@ -1490,6 +1490,14 @@ typedef struct rs6000_args int named; /* false for varargs params */ int escapes; /* if function visible outside tu */ int libcall; /* If this is a compiler generated call. */ + /* 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; + /* 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; } CUMULATIVE_ARGS; /* Initialize a variable CUM of type CUMULATIVE_ARGS -- 2.39.3