From: Pedro Alves <palves@redhat.com>
Date: Sun, 20 Jun 2010 22:23:36 +0000 (+0000)
Subject: 2010-06-20  Ian Lance Taylor  <iant@google.com>
X-Git-Tag: gdb_7_2-branchpoint~185
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9e4344e5eae3650abd27c0a7b384604c4b32c37b;p=thirdparty%2Fbinutils-gdb.git

2010-06-20  Ian Lance Taylor  <iant@google.com>
	    Pedro Alves  <pedro@codesourcery.com>

	* linux-x86-low.c (always_true): Delete.
	(EMIT_ASM, EMIT_ASM32): Use an uncondition asm jmp instead of
	trying to fool the compiler with always_true.
---

diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index f25e40980f4..99aacba1886 100644
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,3 +1,10 @@
+2010-06-20  Ian Lance Taylor  <iant@google.com>
+	    Pedro Alves  <pedro@codesourcery.com>
+
+	* linux-x86-low.c (always_true): Delete.
+	(EMIT_ASM, EMIT_ASM32): Use an uncondition asm jmp instead of
+	trying to fool the compiler with always_true.
+
 2010-06-20  Pedro Alves  <pedro@codesourcery.com>
 
 	* tracepoint.c (condition_true_at_tracepoint): Don't run compiled
diff --git a/gdb/gdbserver/linux-x86-low.c b/gdb/gdbserver/linux-x86-low.c
index 772aaa31535..1e0d684f8e4 100644
--- a/gdb/gdbserver/linux-x86-low.c
+++ b/gdb/gdbserver/linux-x86-low.c
@@ -1484,41 +1484,37 @@ add_insns (unsigned char *start, int len)
   current_insn_ptr = buildaddr;
 }
 
-/* A function used to trick optimizers.  */
-
-int
-always_true (void)
-{
-  return 1;
-}
-
 /* Our general strategy for emitting code is to avoid specifying raw
    bytes whenever possible, and instead copy a block of inline asm
    that is embedded in the function.  This is a little messy, because
    we need to keep the compiler from discarding what looks like dead
    code, plus suppress various warnings.  */
 
-#define EMIT_ASM(NAME,INSNS)						\
-  { extern unsigned char start_ ## NAME, end_ ## NAME;			\
-    add_insns (&start_ ## NAME, &end_ ## NAME - &start_ ## NAME);	\
-    if (always_true ())						\
-      goto skipover ## NAME;						\
-    __asm__ ("start_" #NAME ":\n\t" INSNS "\n\tend_" #NAME ":\n\t");	\
-    skipover ## NAME:							\
-    ; }
-
+#define EMIT_ASM(NAME, INSNS)						\
+  do									\
+    {									\
+      extern unsigned char start_ ## NAME, end_ ## NAME;		\
+      add_insns (&start_ ## NAME, &end_ ## NAME - &start_ ## NAME);	\
+      __asm__ ("jmp end_" #NAME "\n"				\
+	       "\t" "start_" #NAME ":"					\
+	       "\t" INSNS "\n"						\
+	       "\t" "end_" #NAME ":");					\
+    } while (0)
 
 #ifdef __x86_64__
 
 #define EMIT_ASM32(NAME,INSNS)						\
-  { extern unsigned char start_ ## NAME, end_ ## NAME;			\
-    add_insns (&start_ ## NAME, &end_ ## NAME - &start_ ## NAME);	\
-    if (always_true ())						\
-      goto skipover ## NAME;						\
-    __asm__ (".code32\n\tstart_" #NAME ":\n\t" INSNS "\n\tend_" #NAME ":\n" \
-	     "\t.code64\n\t");						\
-    skipover ## NAME:							\
-    ; }
+  do									\
+    {									\
+      extern unsigned char start_ ## NAME, end_ ## NAME;		\
+      add_insns (&start_ ## NAME, &end_ ## NAME - &start_ ## NAME);	\
+      __asm__ (".code32\n"						\
+	       "\t" "jmp end_" #NAME "\n"				\
+	       "\t" "start_" #NAME ":\n"				\
+	       "\t" INSNS "\n"						\
+	       "\t" "end_" #NAME ":\n"					\
+	       ".code64\n");						\
+    } while (0)
 
 #else