https://bugs.kde.org/show_bug.cgi?id=359733
Bug ID: 359733
Summary: amd64 implement strchr/index override to avoid need
for suppression and redirection like x86
Product: valgrind
Version: unspecified
Platform: Other
OS: Linux
Status: UNCONFIRMED
Severity: normal
Priority: NOR
Component: general
Assignee: jsew...@acm.org
Reporter: m...@redhat.com
This was suggested about a year ago in the Fosdem easy hacks presentation:
https://archive.fosdem.org/2015/schedule/event/valgrind_easy_hack/attachments/slides/731/export/events/attachments/valgrind_easy_hack/slides/731/valgrind_easy_hacks.html#slide16
The suppression and redirection isn't needed for x86. When testing a newer
glibc or calling the ld.so through an alternative path neither the suppression
(doesn't match path/name) nor the redirection (triggers too late) works. Since
there is already an hardwire override for strlen in amd64 ld.so it makes sense
to also hardware index (it is always called when ld.so loads the preload
images)
Reproducible: Always
Suggested patch:
diff --git a/coregrind/m_redir.c b/coregrind/m_redir.c
index dcf1fb4..dae47f1 100644
--- a/coregrind/m_redir.c
+++ b/coregrind/m_redir.c
@@ -1353,6 +1353,9 @@ void VG_(redir_initialise) ( void )
if (0==VG_(strcmp)("Memcheck", VG_(details).name)) {
add_hardwired_spec(
+ "ld-linux-x86-64.so.2", "index",
+ (Addr)&VG_(amd64_linux_REDIR_FOR_index), NULL);
+ add_hardwired_spec(
"ld-linux-x86-64.so.2", "strlen",
(Addr)&VG_(amd64_linux_REDIR_FOR_strlen),
# ifndef GLIBC_MANDATORY_STRLEN_REDIRECT
diff --git a/coregrind/m_trampoline.S b/coregrind/m_trampoline.S
index cac2288..176ea66 100644
--- a/coregrind/m_trampoline.S
+++ b/coregrind/m_trampoline.S
@@ -220,6 +220,30 @@ VG_(amd64_linux_REDIR_FOR_strlen):
.LfnE5:
.size VG_(amd64_linux_REDIR_FOR_strlen), .-VG_(amd64_linux_REDIR_FOR_strlen)
+.global VG_(amd64_linux_REDIR_FOR_index)
+.type VG_(amd64_linux_REDIR_FOR_index), @function
+VG_(amd64_linux_REDIR_FOR_index):
+ movzbl (%rdi), %eax
+ movl %esi, %edx
+ cmpb %sil, %al
+ jne .L4
+ jmp .L5
+.L10:
+ addq $1, %rdi
+ movzbl (%rdi), %eax
+ cmpb %dl, %al
+ je .L5
+.L4:
+ testb %al, %al
+ jne .L10
+ xorl %eax, %eax
+ ret
+.L5:
+ movq %rdi, %rax
+ ret
+.size VG_(amd64_linux_REDIR_FOR_index), .-VG_(amd64_linux_REDIR_FOR_index)
+
+
/* A CIE for the above four functions, followed by their FDEs */
.section .eh_frame,"a",@progbits
diff --git a/coregrind/pub_core_trampoline.h b/coregrind/pub_core_trampoline.h
index eda5ec6..1396519 100644
--- a/coregrind/pub_core_trampoline.h
+++ b/coregrind/pub_core_trampoline.h
@@ -71,6 +71,7 @@ extern Addr VG_(amd64_linux_REDIR_FOR_vgettimeofday);
extern Addr VG_(amd64_linux_REDIR_FOR_vtime);
extern Addr VG_(amd64_linux_REDIR_FOR_vgetcpu);
extern UInt VG_(amd64_linux_REDIR_FOR_strlen)( void* );
+extern Char* VG_(amd64_linux_REDIR_FOR_index) ( const Char*, Int );
#endif
#if defined(VGP_ppc32_linux)
diff --git a/shared/vg_replace_strmem.c b/shared/vg_replace_strmem.c
index 005b679..8de085a 100644
--- a/shared/vg_replace_strmem.c
+++ b/shared/vg_replace_strmem.c
@@ -247,7 +247,7 @@ static inline void my_exit ( int x )
STRCHR(VG_Z_LIBC_SONAME, __strchr_sse2)
STRCHR(VG_Z_LIBC_SONAME, __strchr_sse2_no_bsf)
STRCHR(VG_Z_LIBC_SONAME, index)
-# if !defined(VGP_x86_linux)
+# if !defined(VGP_x86_linux) && !defined(VGP_amd64_linux)
STRCHR(VG_Z_LD_LINUX_SO_2, strchr)
STRCHR(VG_Z_LD_LINUX_SO_2, index)
STRCHR(VG_Z_LD_LINUX_X86_64_SO_2, strchr)
--
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