From: Julian Seward <jseward@acm.org>
Date: Wed, 24 Jul 2002 09:33:52 +0000 (+0000)
Subject: Assume PUTF modifies %EFLAGS in a completely arbitrary manner, and so
X-Git-Tag: svn/VALGRIND_1_0_1~6
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=51c33c4afd73815f191957f6f50131e99c774c21;p=thirdparty%2Fvalgrind.git

Assume PUTF modifies %EFLAGS in a completely arbitrary manner, and so
be completely pessimistic if it is encountered during the redundant-flag-
save/restore-elimination pass.  This fixes the following mysterious
failure:

 insane instruction
           27: PUTFL     %ecx

 valgrind: vg_from_ucode.c:2600 (vgPlain_emit_code): Assertion `sane' failed.


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@516
---

diff --git a/coregrind/vg_translate.c b/coregrind/vg_translate.c
index 0a806944ec..27a02754cf 100644
--- a/coregrind/vg_translate.c
+++ b/coregrind/vg_translate.c
@@ -1458,6 +1458,15 @@ static void vg_improve ( UCodeBlock* cb )
          continue;
       } 
 
+      /* PUTF modifies the %EFLAGS in essentially unpredictable ways.
+         For example people try to mess with bit 21 to see if CPUID
+         works.  The setting may or may not actually take hold.  So we
+         play safe here. */
+      if (u->opcode == PUTF) {
+         future_dead_flags = FlagsEmpty;
+         continue;
+      } 
+
       /* We can annul the flags written by this insn if it writes a
          subset (or eq) of the set of flags known to be dead after
          this insn.  If not, just record the flags also written by
diff --git a/vg_translate.c b/vg_translate.c
index 0a806944ec..27a02754cf 100644
--- a/vg_translate.c
+++ b/vg_translate.c
@@ -1458,6 +1458,15 @@ static void vg_improve ( UCodeBlock* cb )
          continue;
       } 
 
+      /* PUTF modifies the %EFLAGS in essentially unpredictable ways.
+         For example people try to mess with bit 21 to see if CPUID
+         works.  The setting may or may not actually take hold.  So we
+         play safe here. */
+      if (u->opcode == PUTF) {
+         future_dead_flags = FlagsEmpty;
+         continue;
+      } 
+
       /* We can annul the flags written by this insn if it writes a
          subset (or eq) of the set of flags known to be dead after
          this insn.  If not, just record the flags also written by