Hi,
Functions using PC-relative addressing do not use a TOC, so there is no need for
a global entry point for TOC setup. Ensure we never generate a global entry
point, and use a .localentry directive that sets the upper st_other bits to 1.
Also change a function name for clarity, and move a var decl off of paths
where it will not be executed, per previous comments by Segher.
Bootstrapped and tested on powerpc64le-unknown-linux-gnu with no regressions.
Is this okay for trunk?
Thanks!
Bill
[gcc]
2019-05-23 Bill Schmidt <wschm...@linux.ibm.com>
* config/rs6000/rs6000.c (rs6000_global_entry_point_needed_p):
Rename to rs6000_global_entry_point_prologue_needed_p. Return
false for PC-relative functions.
(rs6000_output_function_prologue): Change called function name to
rs6000_global_entry_point_prologue_needed_p. Emit ".localentry
name,1" for PC-relative functions.
(rs6000_elf_declare_function_name): Change called function name to
rs6000_global_entry_point_prologue_needed_p.
[gcc/testsuite]
2019-05-23 Bill Schmidt <wschm...@linux.ibm.com>
* gcc.target/powerpc/localentry-1.c: New file.
diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 7a2e43fd72a..3d5cf9e4ece 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -26180,7 +26180,7 @@ split_stack_arg_pointer_used_p (void)
/* Return whether we need to emit an ELFv2 global entry point prologue. */
static bool
-rs6000_global_entry_point_needed_p (void)
+rs6000_global_entry_point_prologue_needed_p (void)
{
/* Only needed for the ELFv2 ABI. */
if (DEFAULT_ABI != ABI_ELFv2)
@@ -26191,6 +26191,10 @@ rs6000_global_entry_point_needed_p (void)
if (TARGET_SINGLE_PIC_BASE)
return false;
+ /* PC-relative functions never generate a global entry point prologue. */
+ if (rs6000_pcrel_p (cfun))
+ return false;
+
/* Ensure we have a global entry point for thunks. ??? We could
avoid that if the target routine doesn't need a global entry point,
but we do not know whether this is the case at this point. */
@@ -27547,10 +27551,9 @@ rs6000_output_function_prologue (FILE *file)
/* ELFv2 ABI r2 setup code and local entry point. This must follow
immediately after the global entry point label. */
- if (rs6000_global_entry_point_needed_p ())
+ if (rs6000_global_entry_point_prologue_needed_p ())
{
const char *name = XSTR (XEXP (DECL_RTL (current_function_decl), 0), 0);
-
(*targetm.asm_out.internal_label) (file, "LCF", rs6000_pic_labelno);
if (TARGET_CMODEL != CMODEL_LARGE)
@@ -27601,6 +27604,19 @@ rs6000_output_function_prologue (FILE *file)
fputs ("\n", file);
}
+ else if (rs6000_pcrel_p (cfun))
+ {
+ const char *name = XSTR (XEXP (DECL_RTL (current_function_decl), 0), 0);
+ /* All functions compiled to use PC-relative addressing will
+ have a .localentry value of 0 or 1. For now we set it to
+ 1 all the time, indicating that the function may clobber
+ the TOC register r2. Later we may optimize this by setting
+ it to 0 if the function is a leaf and does not clobber r2. */
+ fputs ("\t.localentry\t", file);
+ assemble_name (file, name);
+ fputs (",1\n", file);
+ }
+
/* Output -mprofile-kernel code. This needs to be done here instead of
in output_function_profile since it must go after the ELFv2 ABI
local entry point. */
@@ -33335,7 +33351,8 @@ rs6000_elf_declare_function_name (FILE *file, const
char *name, tree decl)
ASM_OUTPUT_TYPE_DIRECTIVE (file, name, "function");
ASM_DECLARE_RESULT (file, DECL_RESULT (decl));
- if (TARGET_CMODEL == CMODEL_LARGE && rs6000_global_entry_point_needed_p ())
+ if (TARGET_CMODEL == CMODEL_LARGE
+ && rs6000_global_entry_point_prologue_needed_p ())
{
char buf[256];
diff --git a/gcc/testsuite/gcc.target/powerpc/localentry-1.c
b/gcc/testsuite/gcc.target/powerpc/localentry-1.c
new file mode 100644
index 00000000000..ce687a7f6ec
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/localentry-1.c
@@ -0,0 +1,18 @@
+/* { dg-do compile } */
+/* { dg-options "-mdejagnu-cpu=future -O2" } */
+/* { dg-require-effective-target powerpc_elfv2 } */
+
+/* Ensure we generate ".localentry fn,1" for both leaf and non-leaf
+ functions. */
+
+extern int y (int);
+
+int x (void)
+{
+ return y (5);
+}
+
+void z (void) { };
+
+/* { dg-final { scan-assembler {\.localentry\t\mx,1\M} } } */
+/* { dg-final { scan-assembler {\.localentry\t\mz,1\M} } } */
