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
