From 42d3ec99172aa644044923678943a70a8c31955c Mon Sep 17 00:00:00 2001
From: whitequark <whitequark@whitequark.org>
Date: Mon, 1 Aug 2016 05:19:21 +0000
Subject: [PATCH] CMake: finish Clang sanitizer support.

This makes ENABLE_SANITIZERS a proper cached variable, removes some
spurious failures and configures asan/ubsan to die on an error.
---
 .travis/build-debian.sh |  6 ++++--
 CMakeLists.txt          | 14 ++++++++++----
 src/resource.cpp        | 14 +++++++++-----
 3 files changed, 23 insertions(+), 11 deletions(-)

diff --git a/.travis/build-debian.sh b/.travis/build-debian.sh
index 2b6db43..e88bd9a 100755
--- a/.travis/build-debian.sh
+++ b/.travis/build-debian.sh
@@ -4,6 +4,8 @@ if echo $TRAVIS_TAG | grep ^v; then BUILD_TYPE=RelWithDebInfo; else BUILD_TYPE=D
 
 mkdir build
 cd build
-cmake -DCMAKE_C_COMPILER=gcc-5 -DCMAKE_CXX_COMPILER=g++-5 \
-  -DCMAKE_BUILD_TYPE=$BUILD_TYPE -DENABLE_COVERAGE=ON ..
+cmake .. -DCMAKE_C_COMPILER=gcc-5 -DCMAKE_CXX_COMPILER=g++-5 \
+  -DCMAKE_BUILD_TYPE=$BUILD_TYPE \
+  -DENABLE_COVERAGE=ON \
+  -DENABLE_SANITIZERS=ON
 make VERBOSE=1
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 15f2365..baa3c16 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -27,10 +27,12 @@ set(solvespace_VERSION_MAJOR 3)
 set(solvespace_VERSION_MINOR 0)
 string(SUBSTRING "${GIT_COMMIT_HASH}" 0 8 solvespace_GIT_HASH)
 
-set(ENABLE_TESTS    ON  CACHE BOOL
+set(ENABLE_TESTS      ON  CACHE BOOL
     "Whether the test suite will be built and run")
-set(ENABLE_COVERAGE OFF CACHE BOOL
+set(ENABLE_COVERAGE   OFF CACHE BOOL
     "Whether code coverage information will be collected")
+set(ENABLE_SANITIZERS OFF CACHE BOOL
+    "Whether to enable Clang's AddressSanitizer and UndefinedBehaviorSanitizer")
 
 if(NOT WIN32 AND NOT APPLE)
     set(GUI gtk2 CACHE STRING "GUI toolkit to use (one of: gtk2 gtk3)")
@@ -58,12 +60,16 @@ if(CMAKE_SYSTEM_NAME STREQUAL "Linux" OR CMAKE_SYSTEM_NAME STREQUAL "FreeBSD")
     set(CMAKE_EXE_LINKER_FLAGS "-Wl,--as-needed ${CMAKE_EXE_LINKER_FLAGS}")
 endif()
 
-if(SANITIZE)
+if(ENABLE_SANITIZE)
     if(NOT (CMAKE_C_COMPILER_ID MATCHES "Clang" AND CMAKE_CXX_COMPILER_ID MATCHES "Clang"))
-        message(ERROR "Sanitizers are only available in Clang/Clang++")
+        message(FATAL_ERROR "Sanitizers are only available when using Clang/Clang++")
     endif()
     set(SANITIZE_FLAGS  "-O1 -fno-omit-frame-pointer -fno-optimize-sibling-calls")
     set(SANITIZE_FLAGS  "${SANITIZE_FLAGS} -fsanitize=address,undefined,integer")
+    set(SANITIZE_FLAGS  "${SANITIZE_FLAGS} -fno-sanitize-recover=undefined,integer")
+    # We assume IEEE floats, which means DIV/0 is defined; but ubsan doesn't do so by default.
+    set(SANITIZE_FLAGS  "${SANITIZE_FLAGS} -fno-sanitize=float-divide-by-zero")
+
     set(CMAKE_C_FLAGS   "${CMAKE_C_FLAGS} ${SANITIZE_FLAGS}")
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${SANITIZE_FLAGS}")
 endif()
diff --git a/src/resource.cpp b/src/resource.cpp
index 3393e16..7980b57 100644
--- a/src/resource.cpp
+++ b/src/resource.cpp
@@ -21,8 +21,8 @@ std::string LoadString(const std::string &name) {
 }
 
 std::string LoadStringFromGzip(const std::string &name) {
-    size_t size;
-    const void *data = LoadResource(name, &size);
+    size_t deflatedSize;
+    const void *data = LoadResource(name, &deflatedSize);
 
     z_stream stream;
     stream.zalloc = Z_NULL;
@@ -33,11 +33,15 @@ std::string LoadStringFromGzip(const std::string &name) {
 
     // Extract length mod 2**32 from the gzip trailer.
     std::string result;
-    ssassert(size >= 4, "Resource too small to have gzip trailer");
-    result.resize(*(uint32_t *)((uintptr_t)data + size - 4));
+    ssassert(deflatedSize >= 4, "Resource too small to have gzip trailer");
+
+    // *(uint32_t *) may perform an unaligned access, so do a memcpy.
+    uint32_t inflatedSize;
+    memcpy(&inflatedSize, (uint32_t *)((uintptr_t)data + deflatedSize - 4), sizeof(uint32_t));
+    result.resize(inflatedSize);
 
     stream.next_in = (Bytef *)data;
-    stream.avail_in = size;
+    stream.avail_in = deflatedSize;
     stream.next_out = (Bytef *)&result[0];
     stream.avail_out = result.length();
     ssassert(inflate(&stream, Z_NO_FLUSH) == Z_STREAM_END, "Cannot inflate resource");