[PATCH, arm] Backport -- Fix ICE during thunk generation with -mlong-calls

[Mihail Ionescu]

Hi All,

This is a backport from trunk for GCC 8 and 7.

SVN revision: r264595.

Regression tested on arm-none-eabi.


gcc/ChangeLog

2018-11-02  Mihail Ionescu  <mihail.ione...@arm.com>

        Backport from mainiline
        2018-09-26  Eric Botcazou  <ebotca...@adacore.com>

        * config/arm/arm.c (arm_reorg): Skip Thumb reorg pass for thunks.
        (arm32_output_mi_thunk): Deal with long calls.

gcc/testsuite/ChangeLog

2018-11-02  Mihail Ionescu  <mihail.ione...@arm.com>

        Backport from mainiline
        2018-09-17  Eric Botcazou  <ebotca...@adacore.com>

        * g++.dg/other/thunk2a.C: New test.
        * g++.dg/other/thunk2b.C: Likewise.


If everything is ok, could someone commit it on my behalf?

Best regards,
   Mihail

diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index 
2ece668219f3ca34883cd882431b0a3c390d4d3c..c68311e0fa192c350d03eb2dd37eca92ae7b3cfa
 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -17663,7 +17663,11 @@ arm_reorg (void)
 
   if (use_cmse)
     cmse_nonsecure_call_clear_caller_saved ();
-  if (TARGET_THUMB1)
+
+  /* We cannot run the Thumb passes for thunks because there is no CFG.  */
+  if (cfun->is_thunk)
+    ;
+  else if (TARGET_THUMB1)
     thumb1_reorg ();
   else if (TARGET_THUMB2)
     thumb2_reorg ();
@@ -26737,6 +26741,8 @@ static void
 arm32_output_mi_thunk (FILE *file, tree, HOST_WIDE_INT delta,
                       HOST_WIDE_INT vcall_offset, tree function)
 {
+  const bool long_call_p = arm_is_long_call_p (function);
+
   /* On ARM, this_regno is R0 or R1 depending on
      whether the function returns an aggregate or not.
   */
@@ -26774,9 +26780,22 @@ arm32_output_mi_thunk (FILE *file, tree, HOST_WIDE_INT 
delta,
       TREE_USED (function) = 1;
     }
   rtx funexp = XEXP (DECL_RTL (function), 0);
+  if (long_call_p)
+    {
+      emit_move_insn (temp, funexp);
+      funexp = temp;
+    }
   funexp = gen_rtx_MEM (FUNCTION_MODE, funexp);
-  rtx_insn * insn = emit_call_insn (gen_sibcall (funexp, const0_rtx, 
NULL_RTX));
+  rtx_insn *insn = emit_call_insn (gen_sibcall (funexp, const0_rtx, NULL_RTX));
   SIBLING_CALL_P (insn) = 1;
+  emit_barrier ();
+
+  /* Indirect calls require a bit of fixup in PIC mode.  */
+  if (long_call_p)
+    {
+      split_all_insns_noflow ();
+      arm_reorg ();
+    }
 
   insn = get_insns ();
   shorten_branches (insn);
diff --git a/gcc/testsuite/g++.dg/other/thunk2a.C 
b/gcc/testsuite/g++.dg/other/thunk2a.C
new file mode 100644
index 
0000000000000000000000000000000000000000..8e5ebd4960df758fa77ff08b019e104870f36b45
--- /dev/null
+++ b/gcc/testsuite/g++.dg/other/thunk2a.C
@@ -0,0 +1,15 @@
+// { dg-do compile { target arm*-*-* } }
+// { dg-options "-mlong-calls -ffunction-sections" }
+
+class a {
+public:
+  virtual ~a();
+};
+
+class b : virtual a {};
+
+class c : b {
+  ~c();
+};
+
+c::~c() {}
diff --git a/gcc/testsuite/g++.dg/other/thunk2b.C 
b/gcc/testsuite/g++.dg/other/thunk2b.C
new file mode 100644
index 
0000000000000000000000000000000000000000..c8f4570923d8bde71547dd343de45edc0efeb2c7
--- /dev/null
+++ b/gcc/testsuite/g++.dg/other/thunk2b.C
@@ -0,0 +1,16 @@
+// { dg-do compile { target arm*-*-* } }
+// { dg-options "-mlong-calls -ffunction-sections" }
+// { dg-additional-options "-fPIC" { target fpic } }
+
+class a {
+public:
+  virtual ~a();
+};
+
+class b : virtual a {};
+
+class c : b {
+  ~c();
+};
+
+c::~c() {}
diff --git a/gcc/testsuite/g++.dg/other/vthunk1.C 
b/gcc/testsuite/g++.dg/other/thunk1.C
similarity index 100%
rename from gcc/testsuite/g++.dg/other/vthunk1.C
rename to gcc/testsuite/g++.dg/other/thunk1.C