From: Tom Hughes <tom@compton.nu>
Date: Thu, 2 Jul 2009 13:02:12 +0000 (+0000)
Subject: Replace strlen on amd64-linux with a simple version that doesn't
X-Git-Tag: svn/VALGRIND_3_5_0~444
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=3ddeb03e5b3e2f109f78a14fe272968173a8167f;p=thirdparty%2Fvalgrind.git

Replace strlen on amd64-linux with a simple version that doesn't
generate false positives.

Patch from Jakub Jelinek <jakub@redhat.com>. Fixes #190429.


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@10402
---

diff --git a/coregrind/m_redir.c b/coregrind/m_redir.c
index d824a79a42..570d996ce5 100644
--- a/coregrind/m_redir.c
+++ b/coregrind/m_redir.c
@@ -879,6 +879,20 @@ void VG_(redir_initialise) ( void )
       (Addr)&VG_(amd64_linux_REDIR_FOR_vtime) 
    );
 
+   /* If we're using memcheck, use these intercepts right from
+      the start, otherwise ld.so makes a lot of noise. */
+   if (0==VG_(strcmp)("Memcheck", VG_(details).name)) {
+
+      static const HChar croakage[]
+        = "Possible fix: install glibc's debuginfo package on this machine.";
+
+      /* this is mandatory - can't sanely continue without it */
+      add_hardwired_spec(
+         "ld-linux-x86-64.so.2", "strlen",
+         (Addr)&VG_(amd64_linux_REDIR_FOR_strlen),
+         croakage
+      );   
+   }
 #  elif defined(VGP_ppc32_linux)
    {
    static const HChar croakage[]
diff --git a/coregrind/m_trampoline.S b/coregrind/m_trampoline.S
index 8b3487ef9f..256666bdf4 100644
--- a/coregrind/m_trampoline.S
+++ b/coregrind/m_trampoline.S
@@ -168,7 +168,29 @@ VG_(amd64_linux_REDIR_FOR_vtime):
 .LfnE3:
 .size VG_(amd64_linux_REDIR_FOR_vtime), .-.LfnB3
 
-/* A CIE for the above two functions, followed by their FDEs */
+/* There's no particular reason that this needs to be handwritten
+   assembly, but since that's what this file contains, here's a
+   simple strlen implementation (written in C and compiled by gcc.)
+*/
+.global VG_(amd64_linux_REDIR_FOR_strlen)
+.type   VG_(amd64_linux_REDIR_FOR_strlen), @function
+VG_(amd64_linux_REDIR_FOR_strlen):
+.LfnB4:
+	xorl	%eax, %eax
+	cmpb	$0, (%rdi)
+	movq	%rdi, %rdx
+	je	.L41
+.L40:	addq	$1, %rdx
+	cmpb	$0, (%rdx)
+	jne	.L40
+	movq	%rdx, %rax
+	subq	%rdi, %rax
+.L41:	ret
+.LfnE4:
+.size VG_(amd64_linux_REDIR_FOR_strlen), .-VG_(amd64_linux_REDIR_FOR_strlen)
+
+
+/* A CIE for the above three functions, followed by their FDEs */
 	.section .eh_frame,"a",@progbits
 .Lframe1:
         .long   .LEcie1-.LScie1
@@ -206,6 +228,15 @@ VG_(amd64_linux_REDIR_FOR_vtime):
         .uleb128 0x0
         .align 8
 .LEfde3:
+.LSfde4:
+        .long   .LEfde4-.LASfde4
+.LASfde4:
+        .long   .LASfde4-.Lframe1
+        .long   .LfnB4
+        .long   .LfnE4-.LfnB4
+        .uleb128 0x0
+        .align 8
+.LEfde4:
 	.previous
 
 .global VG_(trampoline_stuff_end)
diff --git a/coregrind/pub_core_trampoline.h b/coregrind/pub_core_trampoline.h
index c8c6520744..31c591cb94 100644
--- a/coregrind/pub_core_trampoline.h
+++ b/coregrind/pub_core_trampoline.h
@@ -66,6 +66,7 @@ extern Char* VG_(x86_linux_REDIR_FOR_index) ( const Char*, Int );
 extern void VG_(amd64_linux_SUBST_FOR_rt_sigreturn);
 extern void VG_(amd64_linux_REDIR_FOR_vgettimeofday);
 extern void VG_(amd64_linux_REDIR_FOR_vtime);
+extern UInt VG_(amd64_linux_REDIR_FOR_strlen)( void* );
 #endif
 
 #if defined(VGP_ppc32_linux)