From 049d79eff7782e8dc678bc8def4427fe5ab343eb Mon Sep 17 00:00:00 2001
From: Sylvestre Ledru <sylvestre@debian.org>
Date: Mon, 5 Sep 2016 06:59:12 +0000
Subject: [PATCH] Fix asan with libc6 >= 2.24 (asan-glibc-2.24.diff, backport
 of 269633) Many thanks to Michael Stapelberg for the great bug report.
 (Closes: 836723)

---
 debian/changelog                    |  8 +++
 debian/patches/asan-glibc-2.24.diff | 81 +++++++++++++++++++++++++++++
 debian/patches/series               |  1 +
 3 files changed, 90 insertions(+)
 create mode 100644 debian/patches/asan-glibc-2.24.diff

diff --git a/debian/changelog b/debian/changelog
index 887d525e..11797cd4 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,11 @@
+llvm-toolchain-3.8 (1:3.8.1-11) UNRELEASED; urgency=medium
+
+  * Fix asan with libc6 >= 2.24 (asan-glibc-2.24.diff, backport of 269633)
+    Many thanks to Michael Stapelberg for the great bug report.
+    (Closes: 836723)
+
+ -- Sylvestre Ledru <sylvestre@debian.org>  Mon, 05 Sep 2016 08:57:48 +0200
+
 llvm-toolchain-3.8 (1:3.8.1-10) unstable; urgency=medium
 
   * Fix the usage of jsoncpp in polly. Thanks to James Clarke for the patch
diff --git a/debian/patches/asan-glibc-2.24.diff b/debian/patches/asan-glibc-2.24.diff
new file mode 100644
index 00000000..133406d7
--- /dev/null
+++ b/debian/patches/asan-glibc-2.24.diff
@@ -0,0 +1,81 @@
+Index: llvm-toolchain-3.8-3.8.1/compiler-rt/lib/asan/asan_malloc_linux.cc
+===================================================================
+--- llvm-toolchain-3.8-3.8.1.orig/compiler-rt/lib/asan/asan_malloc_linux.cc
++++ llvm-toolchain-3.8-3.8.1/compiler-rt/lib/asan/asan_malloc_linux.cc
+@@ -26,52 +26,58 @@
+ // ---------------------- Replacement functions ---------------- {{{1
+ using namespace __asan;  // NOLINT
+ 
+-static const uptr kCallocPoolSize = 1024;
+-static uptr calloc_memory_for_dlsym[kCallocPoolSize];
++static uptr allocated_for_dlsym;
++static const uptr kDlsymAllocPoolSize = 1024;
++static uptr alloc_memory_for_dlsym[kDlsymAllocPoolSize];
++
++static bool IsInDlsymAllocPool(const void *ptr) {
++  uptr off = (uptr)ptr - (uptr)alloc_memory_for_dlsym;
++  return off < sizeof(alloc_memory_for_dlsym);
++}
+ 
+-static bool IsInCallocPool(const void *ptr) {
+-  sptr off = (sptr)ptr - (sptr)calloc_memory_for_dlsym;
+-  return 0 <= off && off < (sptr)kCallocPoolSize;
++static void *AllocateFromLocalPool(uptr size_in_bytes) {
++  uptr size_in_words = RoundUpTo(size_in_bytes, kWordSize) / kWordSize;
++  void *mem = (void*)&alloc_memory_for_dlsym[allocated_for_dlsym];
++  allocated_for_dlsym += size_in_words;
++  CHECK_LT(allocated_for_dlsym, kDlsymAllocPoolSize);
++  return mem;
+ }
+ 
+ INTERCEPTOR(void, free, void *ptr) {
+   GET_STACK_TRACE_FREE;
+-  if (UNLIKELY(IsInCallocPool(ptr)))
++  if (UNLIKELY(IsInDlsymAllocPool(ptr)))
+     return;
+   asan_free(ptr, &stack, FROM_MALLOC);
+ }
+ 
+ INTERCEPTOR(void, cfree, void *ptr) {
+   GET_STACK_TRACE_FREE;
+-  if (UNLIKELY(IsInCallocPool(ptr)))
++  if (UNLIKELY(IsInDlsymAllocPool(ptr)))
+     return;
+   asan_free(ptr, &stack, FROM_MALLOC);
+ }
+ 
+ INTERCEPTOR(void*, malloc, uptr size) {
++  if (UNLIKELY(!asan_inited))
++    // Hack: dlsym calls malloc before REAL(malloc) is retrieved from dlsym.
++    return AllocateFromLocalPool(size);
+   GET_STACK_TRACE_MALLOC;
+   return asan_malloc(size, &stack);
+ }
+ 
+ INTERCEPTOR(void*, calloc, uptr nmemb, uptr size) {
+-  if (UNLIKELY(!asan_inited)) {
++  if (UNLIKELY(!asan_inited))
+     // Hack: dlsym calls calloc before REAL(calloc) is retrieved from dlsym.
+-    static uptr allocated;
+-    uptr size_in_words = ((nmemb * size) + kWordSize - 1) / kWordSize;
+-    void *mem = (void*)&calloc_memory_for_dlsym[allocated];
+-    allocated += size_in_words;
+-    CHECK(allocated < kCallocPoolSize);
+-    return mem;
+-  }
++    return AllocateFromLocalPool(nmemb * size);
+   GET_STACK_TRACE_MALLOC;
+   return asan_calloc(nmemb, size, &stack);
+ }
+ 
+ INTERCEPTOR(void*, realloc, void *ptr, uptr size) {
+   GET_STACK_TRACE_MALLOC;
+-  if (UNLIKELY(IsInCallocPool(ptr))) {
+-    uptr offset = (uptr)ptr - (uptr)calloc_memory_for_dlsym;
+-    uptr copy_size = Min(size, kCallocPoolSize - offset);
++  if (UNLIKELY(IsInDlsymAllocPool(ptr))) {
++    uptr offset = (uptr)ptr - (uptr)alloc_memory_for_dlsym;
++    uptr copy_size = Min(size, kDlsymAllocPoolSize - offset);
+     void *new_ptr = asan_malloc(size, &stack);
+     internal_memcpy(new_ptr, ptr, copy_size);
+     return new_ptr;
diff --git a/debian/patches/series b/debian/patches/series
index c80f4ef6..763936d6 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -45,3 +45,4 @@ lldb-link-atomic-cmake.patch
 D17567-PR23529-Sema-part-of-attrbute-abi_tag-support.diff
 D18035-PR23529-Mangler-part-of-attrbute-abi_tag-support.diff
 kfreebsd-support.diff
+asan-glibc-2.24.diff