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
