[committed] hppa: Fix handling of large arguments passed by value

[committed] hppa: Fix handling of large arguments passed by value

[John David Anglin]

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This change revises pa_function_arg_size to return values that fit
in an int.  For a number of reasons, updating pa_function_arg,
pa_arg_partial_bytes, etc, to handle handle HOST_WIDE_INT values
didn't seem useful.  Currently, gcc limits the size of arguments
passed by value to 1 GB.  The PA prologue/epilogue code only handles
32-bit frame offsets and 1 GB is the maximum frame size that can be
recorded in the HPUX unwind descriptor.  Thus, limiting argument
sizes to 1 GB is enough.

Tested on hppa64-hp-hpux11.11 and hppa-unknown-linux-gnu.  Committed
to trunk.

Dave
---

Fix handling of large arguments passed by value.

2023-04-15  John David Anglin  <danglin@gcc.gnu.org>

gcc/ChangeLog:

	PR target/109478
	* config/pa/pa-protos.h (pa_function_arg_size): Update prototype.
	* config/pa/pa.cc (pa_function_arg): Return NULL_RTX if argument
	size is zero.
	(pa_arg_partial_bytes): Don't call pa_function_arg_size twice.
	(pa_function_arg_size): Change return type to int.  Return zero
	for arguments larger than 1 GB.  Update comments.

diff --git a/gcc/config/pa/pa-protos.h b/gcc/config/pa/pa-protos.h
index c0a61ea89c3..b4b1310a52d 100644
--- a/gcc/config/pa/pa-protos.h
+++ b/gcc/config/pa/pa-protos.h
@@ -106,7 +106,7 @@ extern void pa_asm_output_aligned_local (FILE *, const char *,
 					 unsigned int);
 extern void pa_hpux_asm_output_external (FILE *, tree, const char *);
 extern HOST_WIDE_INT pa_initial_elimination_offset (int, int);
-extern HOST_WIDE_INT pa_function_arg_size (machine_mode, const_tree);
+extern int pa_function_arg_size (machine_mode, const_tree);
 extern void pa_output_function_label (FILE *);
 extern void hppa_profile_hook (int);
 
diff --git a/gcc/config/pa/pa.cc b/gcc/config/pa/pa.cc
index 3f91ebce603..db633b275e5 100644
--- a/gcc/config/pa/pa.cc
+++ b/gcc/config/pa/pa.cc
@@ -9784,6 +9784,8 @@ pa_function_arg (cumulative_args_t cum_v, const function_arg_info &arg)
     return NULL_RTX;
 
   arg_size = pa_function_arg_size (mode, type);
+  if (!arg_size)
+    return NULL_RTX;
 
   /* If this arg would be passed partially or totally on the stack, then
      this routine should return zero.  pa_arg_partial_bytes will
@@ -9985,15 +9987,16 @@ pa_arg_partial_bytes (cumulative_args_t cum_v, const function_arg_info &arg)
   CUMULATIVE_ARGS *cum = get_cumulative_args (cum_v);
   unsigned int max_arg_words = 8;
   unsigned int offset = 0;
+  int arg_size;
 
   if (!TARGET_64BIT)
     return 0;
 
-  if (pa_function_arg_size (arg.mode, arg.type) > 1 && (cum->words & 1))
+  arg_size = pa_function_arg_size (arg.mode, arg.type);
+  if (arg_size > 1 && (cum->words & 1))
     offset = 1;
 
-  if (cum->words + offset + pa_function_arg_size (arg.mode, arg.type)
-      <= max_arg_words)
+  if (cum->words + offset + arg_size <= max_arg_words)
     /* Arg fits fully into registers.  */
     return 0;
   else if (cum->words + offset >= max_arg_words)
@@ -11067,17 +11070,25 @@ pa_starting_frame_offset (void)
   return 8;
 }
 
-/* Figure out the size in words of the function argument.  The size
-   returned by this function should always be greater than zero because
-   we pass variable and zero sized objects by reference.  */
+/* Figure out the size in words of the function argument.  */
 
-HOST_WIDE_INT
+int
 pa_function_arg_size (machine_mode mode, const_tree type)
 {
   HOST_WIDE_INT size;
 
   size = mode != BLKmode ? GET_MODE_SIZE (mode) : int_size_in_bytes (type); 
-  return CEIL (size, UNITS_PER_WORD);
+
+  /* The 64-bit runtime does not restrict the size of stack frames,
+     but the gcc calling conventions limit argument sizes to 1G.  Our
+     prologue/epilogue code limits frame sizes to just under 32 bits.
+     1G is also the maximum frame size that can be handled by the HPUX
+     unwind descriptor.  Since very large TYPE_SIZE_UNIT values can
+     occur for (parallel:BLK []), we need to ignore large arguments
+     passed by value.  */
+  if (size >= (1 << (HOST_BITS_PER_INT - 2)))
+    size = 0;
+  return (int) CEIL (size, UNITS_PER_WORD);
 }
 
 #include "gt-pa.h"


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