[Qemu-devel] [PATCH 3/5] (PPC) Fix in-between branch returns

[Alexander Graf]

Thanks to the branch detection I found several places where op.o
contained branch returns somewhere not at the end of the function. This
did not happen on other platforms for me, but I may be wrong.

This patch adds FORCE_RET at the end of those functions, to force gcc to
use a jump to the end and not return from it. The idea and most of the
debugging for this comes from Michael Matz.

Index: qemu-snapshot-2008-01-15_05/target-i386/op.c
===================================================================
--- qemu-snapshot-2008-01-15_05.orig/target-i386/op.c
+++ qemu-snapshot-2008-01-15_05/target-i386/op.c
@@ -291,6 +291,7 @@ void OPPROTO op_imull_EAX_T0(void)
     EDX = (uint32_t)(res >> 32);
     CC_DST = res;
     CC_SRC = (res != (int32_t)res);
+    FORCE_RET();
 }
 
 void OPPROTO op_imulw_T0_T1(void)
@@ -300,6 +301,7 @@ void OPPROTO op_imulw_T0_T1(void)
     T0 = res;
     CC_DST = res;
     CC_SRC = (res != (int16_t)res);
+    FORCE_RET();
 }
 
 void OPPROTO op_imull_T0_T1(void)
@@ -309,6 +311,7 @@ void OPPROTO op_imull_T0_T1(void)
     T0 = res;
     CC_DST = res;
     CC_SRC = (res != (int32_t)res);
+    FORCE_RET();
 }
 
 #ifdef TARGET_X86_64
Index: qemu-snapshot-2008-01-15_05/target-i386/ops_template.h
===================================================================
--- qemu-snapshot-2008-01-15_05.orig/target-i386/ops_template.h
+++ qemu-snapshot-2008-01-15_05/target-i386/ops_template.h
@@ -467,6 +467,7 @@ void OPPROTO glue(glue(op_bt, SUFFIX), _
     int count;
     count = T1 & SHIFT_MASK;
     CC_SRC = T0 >> count;
+    FORCE_RET();
 }
 
 void OPPROTO glue(glue(op_bts, SUFFIX), _T0_T1_cc)(void)