Mark helper regs defined in final_tidyup before freeres_wrapper call.

In final_tidyup we setup the guest to call the freeres_wrapper, which
will (possibly) call __gnu_cxx::__freeres() and/or __libc_freeres().

In a couple of cases (ppc64be, ppc64le and mips32) this involves setting
up one or more helper registers. Since we setup these guest registers
we should make sure to mark them as fully defined. Otherwise we might
see spurious warnings about undefined value usage if the guest register
happened to not be fully defined before.

This fixes PR402006.

diff --git a/NEWS b/NEWS
index 562291fa6c70c953af6ac0b3210d9677ecc77d41..d2a42073b5b2dcddf170cefaa7cdc8c18135ee33 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -70,6 +70,7 @@ where XXXXXX is the bug number as listed below.
 401578  drd: crashes sometimes on fork()
 401627  memcheck errors with glibc avx2 optimized wcsncmp
 401822  none/tests/ppc64/jm-vmx fails and produces assembler warnings
+402006  mark helper regs defined in final_tidyup before freeres_wrapper call
 
 Release 3.14.0 (9 October 2018)
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

diff --git a/coregrind/m_main.c b/coregrind/m_main.c
index 00702fc225fcf43d83e802237c8078b51b39d1c9..22872a25a0b60b13c59d96db6cadf8e3f5bba4ba 100644 (file)
--- a/coregrind/m_main.c
+++ b/coregrind/m_main.c
@@ -2304,22 +2304,35 @@ static void final_tidyup(ThreadId tid)
                    "Caught __NR_exit; running %s wrapper\n", msgs[to_run - 1]);
    }
       
-   /* set thread context to point to freeres_wrapper */
-   /* ppc64be-linux note: freeres_wrapper gives us the real
+   /* Set thread context to point to freeres_wrapper.
+      ppc64be-linux note: freeres_wrapper gives us the real
       function entry point, not a fn descriptor, so can use it
       directly.  However, we need to set R2 (the toc pointer)
       appropriately. */
    VG_(set_IP)(tid, freeres_wrapper);
+
 #  if defined(VGP_ppc64be_linux)
    VG_(threads)[tid].arch.vex.guest_GPR2 = r2;
+   VG_TRACK(post_reg_write, Vg_CoreClientReq, tid,
+            offsetof(VexGuestPPC64State, guest_GPR2),
+            sizeof(VG_(threads)[tid].arch.vex.guest_GPR2));
 #  elif  defined(VGP_ppc64le_linux)
    /* setting GPR2 but not really needed, GPR12 is needed */
    VG_(threads)[tid].arch.vex.guest_GPR2  = freeres_wrapper;
+   VG_TRACK(post_reg_write, Vg_CoreClientReq, tid,
+            offsetof(VexGuestPPC64State, guest_GPR2),
+            sizeof(VG_(threads)[tid].arch.vex.guest_GPR2));
    VG_(threads)[tid].arch.vex.guest_GPR12 = freeres_wrapper;
+   VG_TRACK(post_reg_write, Vg_CoreClientReq, tid,
+            offsetof(VexGuestPPC64State, guest_GPR12),
+            sizeof(VG_(threads)[tid].arch.vex.guest_GPR12));
 #  endif
    /* mips-linux note: we need to set t9 */
 #  if defined(VGP_mips32_linux) || defined(VGP_mips64_linux)
    VG_(threads)[tid].arch.vex.guest_r25 = freeres_wrapper;
+   VG_TRACK(post_reg_write, Vg_CoreClientReq, tid,
+            offsetof(VexGuestMIPS32State, guest_r25),
+            sizeof(VG_(threads)[tid].arch.vex.guest_r25));
 #  endif
 
    /* Pass a parameter to freeres_wrapper(). */