x86_64: Fix up -fpic -mcmodel=large -fno-plt [PR98063]

On the following testcase with -fpic -mcmodel=large -fno-plt we emit
call puts@GOTPCREL(%rip)
but that is not really appropriate for CM_LARGE_PIC, the .text can be larger
than 2GB in that case and the .got slot further away from %rip than what can
fit into the signed 32-bit immediate.

The following patch computes the address of the .got slot the way it is
computed for that model for function pointer loads, and calls that.

2020-12-01  Jakub Jelinek  <jakub@redhat.com>

	PR target/98063
	* config/i386/i386-expand.c (ix86_expand_call): Handle non-plt
	CM_LARGE_PIC calls.

	* gcc.target/i386/pr98063.c: New test.

diff --git a/gcc/config/i386/i386-expand.c b/gcc/config/i386/i386-expand.c
index 408cd9baa7897ab274e059818937feb36d94ac2d..bf775a38fc3c2deeaa86f6779f949a5e94b64dba 100644 (file)
--- a/gcc/config/i386/i386-expand.c
+++ b/gcc/config/i386/i386-expand.c
@@ -8063,7 +8063,17 @@ ix86_expand_call (rtx retval, rtx fnaddr, rtx callarg1,
            }
          else if (!TARGET_PECOFF && !TARGET_MACHO)
            {
-             if (TARGET_64BIT)
+             if (TARGET_64BIT
+                 && ix86_cmodel == CM_LARGE_PIC
+                 && DEFAULT_ABI != MS_ABI)
+               {
+                 fnaddr = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, addr),
+                                          UNSPEC_GOT);
+                 fnaddr = gen_rtx_CONST (Pmode, fnaddr);
+                 fnaddr = force_reg (Pmode, fnaddr);
+                 fnaddr = gen_rtx_PLUS (Pmode, pic_offset_table_rtx, fnaddr);
+               }
+             else if (TARGET_64BIT)
                {
                  fnaddr = gen_rtx_UNSPEC (Pmode,
                                           gen_rtvec (1, addr),

diff --git a/gcc/testsuite/gcc.target/i386/pr98063.c b/gcc/testsuite/gcc.target/i386/pr98063.c
new file mode 100644 (file)
index 0000000..f76435a
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr98063.c
@@ -0,0 +1,13 @@
+/* PR target/98063 */
+/* { dg-do run { target { i?86-*-linux* x86_64-*-linux* } } } */
+/* { dg-require-effective-target lp64 } */
+/* { dg-require-effective-target fpic } */
+/* { dg-options "-O2 -fpic -mcmodel=large -fno-plt -save-temps" } */
+/* { dg-final { scan-assembler-not "puts@GOTPCREL" } } */
+
+int
+main ()
+{
+  __builtin_puts ("Hello, world!");
+  return 0;
+}