Index: cmake/config-ix.cmake
===================================================================
--- cmake/config-ix.cmake
+++ cmake/config-ix.cmake
@@ -159,6 +159,7 @@
 set(ALL_CFI_SUPPORTED_ARCH ${X86} ${X86_64} ${MIPS64})
 set(ALL_ESAN_SUPPORTED_ARCH ${X86_64})
 set(ALL_SCUDO_SUPPORTED_ARCH ${X86_64})
+set(ALL_CSI_SUPPORTED_ARCH ${X86_64})
 
 if(APPLE)
   include(CompilerRTDarwinUtils)
@@ -348,6 +349,9 @@
   list_intersect(SCUDO_SUPPORTED_ARCH
     ALL_SCUDO_SUPPORTED_ARCH
     SANITIZER_COMMON_SUPPORTED_ARCH)
+  list_intersect(CSI_SUPPORTED_ARCH
+    ALL_CSI_SUPPORTED_ARCH
+    SANITIZER_COMMON_SUPPORTED_ARCH)
 else()
   # Architectures supported by compiler-rt libraries.
   filter_available_targets(SANITIZER_COMMON_SUPPORTED_ARCH
@@ -371,6 +375,7 @@
   filter_available_targets(ESAN_SUPPORTED_ARCH ${ALL_ESAN_SUPPORTED_ARCH})
   filter_available_targets(SCUDO_SUPPORTED_ARCH
     ${ALL_SCUDO_SUPPORTED_ARCH})
+  filter_available_targets(CSI_SUPPORTED_ARCH ${ALL_CSI_SUPPORTED_ARCH})
 endif()
 
 if (MSVC)
@@ -491,3 +496,9 @@
   set(COMPILER_RT_HAS_SCUDO FALSE)
 endif()
 
+if (COMPILER_RT_HAS_SANITIZER_COMMON AND CSI_SUPPORTED_ARCH AND
+    OS_NAME MATCHES "Linux")
+  set(COMPILER_RT_HAS_CSI TRUE)
+else()
+  set(COMPILER_RT_HAS_CSI FALSE)
+endif()
Index: lib/CMakeLists.txt
===================================================================
--- lib/CMakeLists.txt
+++ lib/CMakeLists.txt
@@ -56,4 +56,8 @@
   if(COMPILER_RT_HAS_SCUDO)
     add_subdirectory(scudo)
   endif()
+  
+  if(COMPILER_RT_HAS_CSI)
+    add_subdirectory(csi)
+  endif()
 endif()
Index: lib/csi/CMakeLists.txt
===================================================================
--- /dev/null
+++ lib/csi/CMakeLists.txt
@@ -0,0 +1,26 @@
+# Build for the ComprehensiveStaticInstrumentation runtime support library.
+
+add_custom_target(csi)
+
+set(CSI_RTL_CFLAGS ${SANITIZER_COMMON_CFLAGS} -std=c11)
+append_rtti_flag(OFF CSI_RTL_CFLAGS)
+
+include_directories(..)
+
+set(CSI_SOURCES csirt.c)
+
+foreach (arch ${CSI_SUPPORTED_ARCH})
+  add_compiler_rt_runtime(clang_rt.csi
+    STATIC
+    ARCHS ${arch}
+    SOURCES ${CSI_SOURCES}
+    CFLAGS ${CSI_RTL_CFLAGS})
+  add_dependencies(csi
+    clang_rt.csi-${arch})
+endforeach()
+
+add_dependencies(compiler-rt csi)
+
+if (COMPILER_RT_INCLUDE_TESTS)
+  # TODO(bruening): add tests via add_subdirectory(tests)
+endif()
Index: lib/csi/csi.h
===================================================================
--- /dev/null
+++ lib/csi/csi.h
@@ -0,0 +1,100 @@
+#ifndef __CSI_H__
+#define __CSI_H__
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+#define EXTERN_C extern "C" {
+#define EXTERN_C_END }
+#else
+#define EXTERN_C
+#define EXTERN_C_END
+#include <stdbool.h> // for C99 bool type
+#endif
+
+#define WEAK __attribute__((weak))
+
+// API function signatures
+EXTERN_C
+
+/**
+ * Unless a type requires bitwise operations (e.g., property lists), we use
+ * signed integers. We don't need the extra bit of data, and using unsigned
+ * integers can lead to subtle bugs. See
+ * http://www.soundsoftware.ac.uk/c-pitfall-unsigned
+ */
+
+typedef int64_t csi_id_t;
+
+#define UNKNOWN_CSI_ID ((csi_id_t)-1)
+
+typedef struct {
+  csi_id_t num_bb;
+  csi_id_t num_callsite;
+  csi_id_t num_func;
+  csi_id_t num_func_exit;
+  csi_id_t num_load;
+  csi_id_t num_store;
+} instrumentation_counts_t;
+
+WEAK void __csi_init();
+
+WEAK void __csi_unit_init(const char * const file_name,
+                          const instrumentation_counts_t counts);
+
+WEAK void __csi_func_entry(const csi_id_t func_id);
+
+WEAK void __csi_func_exit(const csi_id_t func_exit_id,
+                          const csi_id_t func_id);
+
+WEAK void __csi_bb_entry(const csi_id_t bb_id);
+
+WEAK void __csi_bb_exit(const csi_id_t bb_id);
+
+WEAK void __csi_before_call(const csi_id_t call_id, const csi_id_t func_id);
+
+WEAK void __csi_after_call(const csi_id_t call_id, const csi_id_t func_id);
+
+WEAK void __csi_before_load(const csi_id_t load_id,
+                            const void *addr,
+                            const int32_t num_bytes,
+                            const uint64_t prop);
+
+WEAK void __csi_after_load(const csi_id_t load_id,
+                           const void *addr,
+                           const int32_t num_bytes,
+                           const uint64_t prop);
+
+WEAK void __csi_before_store(const csi_id_t store_id,
+                             const void *addr,
+                             const int32_t num_bytes,
+                             const uint64_t prop);
+
+WEAK void __csi_after_store(const csi_id_t store_id,
+                            const void *addr,
+                            const int32_t num_bytes,
+                            const uint64_t prop);
+
+typedef struct {
+    // TODO(ddoucet): Why is this 32 bits?
+    int32_t line_number;
+    char *filename;
+} source_loc_t;
+
+// Front-end data (FED) table accessors.
+source_loc_t const * __csi_get_func_source_loc(const csi_id_t func_id);
+source_loc_t const * __csi_get_func_exit_source_loc(const csi_id_t func_exit_id);
+source_loc_t const * __csi_get_bb_source_loc(const csi_id_t bb_id);
+source_loc_t const * __csi_get_callsite_source_loc(const csi_id_t call_id);
+source_loc_t const * __csi_get_load_source_loc(const csi_id_t load_id);
+source_loc_t const * __csi_get_store_source_loc(const csi_id_t store_id);
+
+// Property bitmasks.
+
+// Load property: the load is a read-before-write on the address in
+// the same basic block.
+#define CSI_PROP_LOAD_READ_BEFORE_WRITE_IN_BB 0x1
+
+EXTERN_C_END
+
+#endif
Index: lib/csi/csirt.c
===================================================================
--- /dev/null
+++ lib/csi/csirt.c
@@ -0,0 +1,189 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <assert.h>
+
+#include "csi.h"
+
+#define CSIRT_API __attribute__((visibility("default")))
+
+// ------------------------------------------------------------------------
+// Front end data (FED) table structures.
+// ------------------------------------------------------------------------
+
+// A FED table is a flat list of FED entries, indexed by a CSI
+// ID. Each FED table has its own private ID space.
+typedef struct {
+    int64_t num_entries;
+    source_loc_t *entries;
+} fed_table_t;
+
+// Types of FED tables that we maintain across all units.
+typedef enum {
+    FED_TYPE_BASICBLOCK,
+    FED_TYPE_FUNCTIONS,
+    FED_TYPE_FUNCTION_EXIT,
+    FED_TYPE_CALLSITE,
+    FED_TYPE_LOAD,
+    FED_TYPE_STORE,
+    NUM_FED_TYPES // Must be last
+} fed_type_t;
+
+// ------------------------------------------------------------------------
+// Globals
+// ------------------------------------------------------------------------
+
+// The list of FED tables. This is indexed by a value of
+// 'fed_type_t'.
+static fed_table_t *fed_tables = NULL;
+
+// Initially false, set to true once the first unit is initialized,
+// which results in the FED list being initialized.
+static bool fed_tables_initialized = false;
+
+// Initially false, set to true once the first unit is initialized,
+// which results in the __csi_init() function being called.
+static bool csi_init_called = false;
+
+// ------------------------------------------------------------------------
+// Private function definitions
+// ------------------------------------------------------------------------
+
+// Initialize the FED tables list, indexed by a value of type
+// fed_type_t. This is called once, by the first unit to load.
+static void initialize_fed_tables() {
+    fed_tables = (fed_table_t *)malloc(NUM_FED_TYPES * sizeof(fed_table_t));
+    assert(fed_tables != NULL);
+    for (unsigned i = 0; i < NUM_FED_TYPES; i++) {
+        fed_table_t table;
+        table.num_entries = 0;
+        table.entries = NULL;
+        fed_tables[i] = table;
+    }
+    fed_tables_initialized = true;
+}
+
+// Ensure that the FED table of the given type has enough memory
+// allocated to add a new unit's entries.
+static void ensure_fed_table_capacity(fed_type_t fed_type, int64_t num_new_entries) {
+    if (!fed_tables_initialized) {
+        initialize_fed_tables();
+    }
+    fed_table_t *table = &fed_tables[fed_type];
+    int64_t total_num_entries = table->num_entries + num_new_entries;
+    if (total_num_entries > 0) {
+        table->entries = (source_loc_t *)realloc(table->entries,
+                                                 total_num_entries * sizeof(source_loc_t));
+        table->num_entries = total_num_entries;
+        assert(table->entries != NULL);
+    }
+}
+
+// Add a new FED table of the given type.
+static inline void add_fed_table(fed_type_t fed_type, int64_t num_entries, source_loc_t const * fed_entries) {
+    ensure_fed_table_capacity(fed_type, num_entries);
+    fed_table_t *table = &fed_tables[fed_type];
+    csi_id_t base = table->num_entries - num_entries;
+    for (csi_id_t i = 0; i < num_entries; i++) {
+        table->entries[base + i] = fed_entries[i];
+    }
+}
+
+// The unit-local counter pointed to by 'fed_id_base' keeps track of
+// that unit's "base" ID value of the given type (recall that there is
+// a private ID space per FED type). The "base" ID value is the global
+// ID that corresponds to the unit's local ID 0. This function stores
+// the correct value into a unit's base ID.
+static inline void update_ids(fed_type_t fed_type, int64_t num_entries, csi_id_t *fed_id_base) {
+    fed_table_t *table = &fed_tables[fed_type];
+    // The base ID is the current number of FED entries before adding
+    // the new FED table.
+    *fed_id_base = table->num_entries - num_entries;
+}
+
+// Return the FED entry of the given type, corresponding to the given
+// CSI ID.
+static inline source_loc_t const * get_fed_entry(fed_type_t fed_type, const csi_id_t csi_id) {
+    // TODO(ddoucet): threadsafety
+    fed_table_t *table = &fed_tables[fed_type];
+    if (csi_id < table->num_entries) {
+        assert(table->entries != NULL);
+        return &table->entries[csi_id];
+    } else {
+        return NULL;
+    }
+}
+
+// ------------------------------------------------------------------------
+// External function definitions, including CSIRT API functions.
+// ------------------------------------------------------------------------
+
+EXTERN_C
+
+typedef struct {
+    int64_t num_entries;
+    csi_id_t *id_base;
+    source_loc_t const * entries;
+} unit_fed_table_t;
+
+// Function signature for the function (generated by the CSI compiler
+// pass) that updates the callsite to function ID mappings.
+typedef void (*__csi_init_callsite_to_functions)();
+
+static inline instrumentation_counts_t compute_inst_counts(unit_fed_table_t *unit_fed_tables) {
+    instrumentation_counts_t counts;
+    int64_t *base = (int64_t *)&counts;
+    for (unsigned i = 0; i < NUM_FED_TYPES; i++)
+        *(base + i) = unit_fed_tables[i].num_entries;
+    return counts;
+}
+
+// A call to this is inserted by the CSI compiler pass, and occurs
+// before main().
+CSIRT_API void __csirt_unit_init(const char * const name,
+                       unit_fed_table_t *unit_fed_tables,
+                       __csi_init_callsite_to_functions callsite_to_func_init) {
+    // TODO(ddoucet): threadsafety
+    if (!csi_init_called) {
+        __csi_init();
+        csi_init_called = true;
+    }
+
+    // Add all FED tables from the new unit
+    for (unsigned i = 0; i < NUM_FED_TYPES; i++) {
+        add_fed_table(i, unit_fed_tables[i].num_entries, unit_fed_tables[i].entries);
+        update_ids(i, unit_fed_tables[i].num_entries, unit_fed_tables[i].id_base);
+    }
+
+    // Initialize the callsite -> function mappings. This must happen
+    // after the base IDs have been updated.
+    callsite_to_func_init();
+
+    // Call into the tool implementation.
+    __csi_unit_init(name, compute_inst_counts(unit_fed_tables));
+}
+
+CSIRT_API source_loc_t const * __csi_get_func_source_loc(const csi_id_t func_id) {
+    return get_fed_entry(FED_TYPE_FUNCTIONS, func_id);
+}
+
+CSIRT_API source_loc_t const * __csi_get_func_exit_source_loc(const csi_id_t func_exit_id) {
+    return get_fed_entry(FED_TYPE_FUNCTION_EXIT, func_exit_id);
+}
+
+CSIRT_API source_loc_t const * __csi_get_bb_source_loc(const csi_id_t bb_id) {
+    return get_fed_entry(FED_TYPE_BASICBLOCK, bb_id);
+}
+
+CSIRT_API source_loc_t const * __csi_get_callsite_source_loc(const csi_id_t callsite_id) {
+    return get_fed_entry(FED_TYPE_CALLSITE, callsite_id);
+}
+
+CSIRT_API source_loc_t const * __csi_get_load_source_loc(const csi_id_t load_id) {
+    return get_fed_entry(FED_TYPE_LOAD, load_id);
+}
+
+CSIRT_API source_loc_t const * __csi_get_store_source_loc(const csi_id_t store_id) {
+    return get_fed_entry(FED_TYPE_STORE, store_id);
+}
+
+EXTERN_C_END
Index: test/CMakeLists.txt
===================================================================
--- test/CMakeLists.txt
+++ test/CMakeLists.txt
@@ -76,6 +76,9 @@
   if(COMPILER_RT_HAS_SCUDO)
     add_subdirectory(scudo)
   endif()
+  if(COMPILER_RT_HAS_CSI)
+    add_subdirectory(csi)
+  endif()
 endif()
 
 if(COMPILER_RT_STANDALONE_BUILD)
Index: test/csi/CMakeLists.txt
===================================================================
--- /dev/null
+++ test/csi/CMakeLists.txt
@@ -0,0 +1,36 @@
+set(CSI_TEST_DEPS ${SANITIZER_COMMON_LIT_TEST_DEPS})
+
+if(NOT COMPILER_RT_STANDALONE_BUILD)
+  list(APPEND CSI_TEST_DEPS csi)
+endif()
+
+# Add a dependency on the LTO plugin.
+if(LLVM_BINUTILS_INCDIR)
+  list(APPEND CSI_TEST_DEPS LLVMgold)
+endif()
+
+set(CSI_TESTSUITES)
+
+set(CSI_TEST_ARCH ${CSI_SUPPORTED_ARCH})
+
+set(CSI_LIT_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR})
+
+foreach(arch ${CSI_TEST_ARCH})
+  set(CSI_TEST_TARGET_ARCH ${arch})
+  string(TOLOWER "-${arch}" CSI_TEST_CONFIG_SUFFIX)
+  get_target_flags_for_arch(${arch} CSI_TEST_TARGET_CFLAGS)
+  string(REPLACE ";" " " CSI_TEST_TARGET_CFLAGS "${CSI_TEST_TARGET_CFLAGS}")
+
+  string(TOUPPER ${arch} ARCH_UPPER_CASE)
+  set(CONFIG_NAME ${ARCH_UPPER_CASE}Config)
+
+  configure_lit_site_cfg(
+    ${CMAKE_CURRENT_SOURCE_DIR}/lit.site.cfg.in
+    ${CMAKE_CURRENT_BINARY_DIR}/${CONFIG_NAME}/lit.site.cfg)
+  list(APPEND CSI_TESTSUITES ${CMAKE_CURRENT_BINARY_DIR}/${CONFIG_NAME})
+endforeach()
+
+add_lit_testsuite(check-csi "Running ComprehensiveStaticInstrumentation tests"
+  ${CSI_TESTSUITES}
+  DEPENDS ${CSI_TEST_DEPS})
+set_target_properties(check-csi PROPERTIES FOLDER "Csi tests")
Index: test/csi/fed-test.c
===================================================================
--- /dev/null
+++ test/csi/fed-test.c
@@ -0,0 +1,20 @@
+// RUN: %clang_csi_toolc %tooldir/null-tool.c -o %t-null-tool.o
+// RUN: %clang_csi_toolc %tooldir/fed-test-tool.c -o %t-tool.o
+// RUN: %link_csi %t-tool.o %t-null-tool.o -o %t-tool.o
+// RUN: %clang_csi_c %s -o %t.o
+// RUN: %clang_csi %t.o %t-tool.o %csirtlib -o %t
+// RUN: %run %t | FileCheck %s
+
+#include <stdio.h>
+
+static void foo() {
+  printf("In foo.\n");
+}
+
+int main(int argc, char **argv) {
+  printf("In main.\n");
+  foo();
+  // CHECK: Enter function 0 [{{.*}}fed-test.c:14]
+  // CHECK: Enter function 1 [{{.*}}fed-test.c:10]
+  return 0;
+}
Index: test/csi/function-call-count.c
===================================================================
--- /dev/null
+++ test/csi/function-call-count.c
@@ -0,0 +1,15 @@
+// RUN: %clang_csi_toolc %tooldir/null-tool.c -o %t-null-tool.o
+// RUN: %clang_csi_toolc %tooldir/function-call-count-tool.c -o %t-tool.o
+// RUN: %link_csi %t-tool.o %t-null-tool.o -o %t-tool.o
+// RUN: %clang_csi_c %s -o %t.o
+// RUN: %clang_csi %t.o %t-tool.o %csirtlib -o %t
+// RUN: %run %t | FileCheck %s
+
+#include <stdio.h>
+
+int main(int argc, char **argv) {
+  printf("One call.\n");
+  printf("Two calls.\n");
+  // CHECK: num_function_calls = 2
+  return 0;
+}
Index: test/csi/lit.cfg
===================================================================
--- /dev/null
+++ test/csi/lit.cfg
@@ -0,0 +1,51 @@
+# -*- Python -*-
+
+import glob
+import os
+
+# Setup config name.
+config.name = 'ComprehensiveStaticInstrumentation' + config.name_suffix
+
+# Setup source root.
+config.test_source_root = os.path.dirname(__file__)
+
+# Setup default compiler flags used with -fcsi option.
+base_cflags = ([config.target_cflags] + config.debug_info_flags)
+base_cxxflags = config.cxx_mode_flags + base_cflags
+
+llvm_link = os.path.join(config.llvm_tools_dir, "llvm-link")
+
+csi_libdir = os.path.join(config.test_source_root, "..", "..", "lib", "csi")
+csi_rt_lib = os.path.join(config.compiler_rt_libdir, "libclang_rt.csi-%s.a" % config.target_arch)
+csi_testtoolsdir = os.path.join(config.test_source_root, "tools")
+csi_testsupportdir = os.path.join(config.test_source_root, "support")
+
+csi_tool_cflags = (["-g", "-O0", "-c", "-emit-llvm", "-I" + csi_libdir] + base_cflags)
+csi_compile_cflags = (["-g", "-O0", "-c", "-fcsi", "-emit-llvm", "-I" + csi_libdir] + base_cflags)
+csi_cflags = (["-g", "-O0", "-flto", "-fuse-ld=gold"] + base_cflags)
+
+def build_invocation(compile_flags):
+  return " " + " ".join([config.clang] + compile_flags) + " "
+
+config.substitutions.append(("%clang_csi ",
+                             build_invocation(csi_cflags)))
+config.substitutions.append(("%link_csi ",
+                             llvm_link + " "))
+config.substitutions.append(("%clang_csi_c ",
+                             build_invocation(csi_compile_cflags)))
+config.substitutions.append(("%clang_csi_toolc ",
+                             build_invocation(csi_tool_cflags)))
+config.substitutions.append(("%tooldir", csi_testtoolsdir))
+config.substitutions.append(("%supportdir", csi_testsupportdir))
+config.substitutions.append(("%csirtlib", csi_rt_lib))
+
+# Default test suffixes.
+config.suffixes = ['.c', '.cpp']
+
+# Ignore 'tools- and 'support'
+config.excludes.update(map(os.path.basename, glob.glob(os.path.join(csi_testtoolsdir, "*"))))
+config.excludes.update(map(os.path.basename, glob.glob(os.path.join(csi_testsupportdir, "*"))))
+
+# CSI tests are currently supported on Linux x86-64 only.
+if config.host_os not in ['Linux'] or config.target_arch != 'x86_64':
+  config.unsupported = True
Index: test/csi/lit.site.cfg.in
===================================================================
--- /dev/null
+++ test/csi/lit.site.cfg.in
@@ -0,0 +1,14 @@
+## Autogenerated by LLVM/Clang configuration.
+# Do not edit!
+
+# Tool-specific config options.
+config.name_suffix = "@CSI_TEST_CONFIG_SUFFIX@"
+config.csi_lit_source_dir = "@CSI_LIT_SOURCE_DIR@"
+config.target_cflags = "@CSI_TEST_TARGET_CFLAGS@"
+config.target_arch = "@CSI_TEST_TARGET_ARCH@"
+
+# Load common config for all compiler-rt lit tests.
+lit_config.load_config(config, "@COMPILER_RT_BINARY_DIR@/test/lit.common.configured")
+
+# Load tool-specific config that would do the real work.
+lit_config.load_config(config, "@CSI_LIT_SOURCE_DIR@/lit.cfg")
Index: test/csi/load-property-test.c
===================================================================
--- /dev/null
+++ test/csi/load-property-test.c
@@ -0,0 +1,22 @@
+// RUN: %clang_csi_toolc %tooldir/null-tool.c -o %t-null-tool.o
+// RUN: %clang_csi_toolc %tooldir/load-property-test-tool.c -o %t-tool.o
+// RUN: %link_csi %t-tool.o %t-null-tool.o -o %t-tool.o
+// RUN: %clang_csi_c %s -o %t.o
+// RUN: %clang_csi %t.o %t-tool.o %csirtlib -o %t
+// RUN: %run %t | FileCheck %s
+
+#include <stdio.h>
+
+static int global = 0;
+
+int main(int argc, char **argv) {
+  int x = global + 1;               // Read-before-write on global
+  printf("x is %d\n", x);           // Read-before-write on x
+  global = 1;                       // Write on global
+  x = global + 1;                   // Read on global; write on x
+  printf("x is %d\n", x);           // Read on x
+  printf("global is %d\n", global); // Read on global
+  // CHECK: num_loads = 5
+  // CHECK: num_read_before_writes = 2
+  return 0;
+}
Index: test/csi/multiple-units-function-call-count.c
===================================================================
--- /dev/null
+++ test/csi/multiple-units-function-call-count.c
@@ -0,0 +1,21 @@
+// RUN: %clang_csi_toolc %tooldir/null-tool.c -o %t-null-tool.o
+// RUN: %clang_csi_toolc %tooldir/function-call-count-tool.c -o %t-tool.o
+// RUN: %link_csi %t-tool.o %t-null-tool.o -o %t-tool.o
+// RUN: %clang_csi_c %s -o %t.o
+// RUN: %clang_csi_c %supportdir/a.c -o %t.a.o
+// RUN: %clang_csi_c %supportdir/b.c -o %t.b.o
+// RUN: %clang_csi %t.o %t.a.o %t.b.o %t-tool.o %csirtlib -o %t
+// RUN: %run %t | FileCheck %s
+
+#include <stdio.h>
+
+#include "support/a.h"
+
+int main(int argc, char **argv) {
+  printf("One call.\n");
+  printf("Two calls.\n");
+  a();
+  // Calls are: main + a + b + one printf each.
+  // CHECK: num_function_calls = 6
+  return 0;
+}
Index: test/csi/shobj-function-call-count.c
===================================================================
--- /dev/null
+++ test/csi/shobj-function-call-count.c
@@ -0,0 +1,19 @@
+// RUN: %clang_csi_toolc %tooldir/null-tool.c -o %t-null-tool.o
+// RUN: %clang_csi_toolc %tooldir/function-call-count-tool.c -o %t-tool.o
+// RUN: %link_csi %t-tool.o %t-null-tool.o -o %t-tool.o
+// RUN: %clang_csi_c -fPIC %supportdir/libtest.c -o %t-libtest.o
+// RUN: %clang_csi -Wl,-soname,libtest.so -shared %t-libtest.o %t-tool.o -o %t-libtest.so
+// RUN: %clang_csi_c %s -o %t.o
+// RUN: %clang_csi -Wl,-rpath,%T -L %T %t.o %t-tool.o -ltest %csirtlib -o %t
+// RUN: %run %t | FileCheck %s
+
+#include <stdio.h>
+#include "support/libtest.h"
+
+int main(int argc, char **argv) {
+  printf("One call.\n");
+  printf("Two calls.\n");
+  libtest();
+  // CHECK: num_function_calls = 4
+  return 0;
+}
Index: test/csi/support/a.h
===================================================================
--- /dev/null
+++ test/csi/support/a.h
@@ -0,0 +1 @@
+void a();
Index: test/csi/support/a.c
===================================================================
--- /dev/null
+++ test/csi/support/a.c
@@ -0,0 +1,7 @@
+#include <stdio.h>
+#include "b.h"
+
+void a() {
+  printf("In a.\n");
+  b();
+}
Index: test/csi/support/b.h
===================================================================
--- /dev/null
+++ test/csi/support/b.h
@@ -0,0 +1 @@
+void b();
Index: test/csi/support/b.c
===================================================================
--- /dev/null
+++ test/csi/support/b.c
@@ -0,0 +1,5 @@
+#include <stdio.h>
+
+void b() {
+  printf("In b.\n");
+}
Index: test/csi/support/libtest.h
===================================================================
--- /dev/null
+++ test/csi/support/libtest.h
@@ -0,0 +1 @@
+void libtest();
Index: test/csi/support/libtest.c
===================================================================
--- /dev/null
+++ test/csi/support/libtest.c
@@ -0,0 +1,5 @@
+#include <stdio.h>
+
+void libtest() {
+  printf("In libtest.\n");
+}
Index: test/csi/tools/fed-test-tool.c
===================================================================
--- /dev/null
+++ test/csi/tools/fed-test-tool.c
@@ -0,0 +1,9 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include "csi.h"
+
+void __csi_func_entry(const csi_id_t func_id) {
+    printf("Enter function %ld [%s:%d]\n", func_id,
+           __csi_get_func_source_loc(func_id)->filename,
+           __csi_get_func_source_loc(func_id)->line_number);
+}
Index: test/csi/tools/function-call-count-tool.c
===================================================================
--- /dev/null
+++ test/csi/tools/function-call-count-tool.c
@@ -0,0 +1,18 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include "csi.h"
+
+static int num_function_calls = 0;
+
+void report() {
+    printf("num_function_calls = %d\n", num_function_calls);
+}
+
+void __csi_init() {
+    num_function_calls = 0;
+    atexit(report);
+}
+
+void __csi_before_call(const csi_id_t call_id, const csi_id_t func_id) {
+    num_function_calls++;
+}
Index: test/csi/tools/load-property-test-tool.c
===================================================================
--- /dev/null
+++ test/csi/tools/load-property-test-tool.c
@@ -0,0 +1,21 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include "csi.h"
+
+static int num_loads = 0, num_read_before_writes = 0;
+
+void report() {
+    printf("num_loads = %d\n", num_loads);
+    printf("num_read_before_writes = %d\n", num_read_before_writes);
+}
+
+void __csi_init() {
+    num_loads = num_read_before_writes = 0;
+    atexit(report);
+}
+
+void __csi_before_load(const csi_id_t load_id, const void *addr,
+                       const int32_t num_bytes, const uint64_t prop) {
+    num_loads++;
+    if (prop & CSI_PROP_LOAD_READ_BEFORE_WRITE_IN_BB) num_read_before_writes++;
+}
Index: test/csi/tools/null-tool.c
===================================================================
--- /dev/null
+++ test/csi/tools/null-tool.c
@@ -0,0 +1,39 @@
+#include "csi.h"
+
+WEAK void __csi_init() {}
+
+WEAK void __csi_unit_init(const char * const file_name,
+                          const instrumentation_counts_t counts) {}
+
+WEAK void __csi_before_load(const csi_id_t load_id,
+                            const void *addr,
+                            const int32_t num_bytes,
+                            const uint64_t prop) {}
+
+WEAK void __csi_after_load(const csi_id_t load_id,
+                           const void *addr,
+                           const int32_t num_bytes,
+                           const uint64_t prop) {}
+
+WEAK void __csi_before_store(const csi_id_t store_id,
+                             const void *addr,
+                             const int32_t num_bytes,
+                             const uint64_t prop) {}
+
+WEAK void __csi_after_store(const csi_id_t store_id,
+                            const void *addr,
+                            const int32_t num_bytes,
+                            const uint64_t prop) {}
+
+WEAK void __csi_func_entry(const csi_id_t func_id) {}
+
+WEAK void __csi_func_exit(const csi_id_t func_exit_id,
+                          const csi_id_t func_id) {}
+
+WEAK void __csi_bb_entry(const csi_id_t bb_id) {}
+
+WEAK void __csi_bb_exit(const csi_id_t bb_id) {}
+
+WEAK void __csi_before_call(csi_id_t callsite_id, csi_id_t func_id) {}
+
+WEAK void __csi_after_call(csi_id_t callsite_id, csi_id_t func_id) {}
Index: test/csi/tools/unknown-function-call-count-tool.c
===================================================================
--- /dev/null
+++ test/csi/tools/unknown-function-call-count-tool.c
@@ -0,0 +1,20 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include "csi.h"
+
+static int num_function_calls = 0, num_unknown_function_calls = 0;
+
+void report() {
+    printf("num_function_calls = %d\n", num_function_calls);
+    printf("num_unknown_function_calls = %d\n", num_unknown_function_calls);
+}
+
+void __csi_init() {
+    num_function_calls = num_unknown_function_calls = 0;
+    atexit(report);
+}
+
+void __csi_before_call(const csi_id_t call_id, const csi_id_t func_id) {
+    num_function_calls++;
+    if (func_id == UNKNOWN_CSI_ID) num_unknown_function_calls++;
+}
Index: test/csi/unknown-function-call-count.c
===================================================================
--- /dev/null
+++ test/csi/unknown-function-call-count.c
@@ -0,0 +1,21 @@
+// RUN: %clang_csi_toolc %tooldir/null-tool.c -o %t-null-tool.o
+// RUN: %clang_csi_toolc %tooldir/unknown-function-call-count-tool.c -o %t-tool.o
+// RUN: %link_csi %t-tool.o %t-null-tool.o -o %t-tool.o
+// RUN: %clang_csi_c %s -o %t.o
+// RUN: %clang_csi %t.o %t-tool.o %csirtlib -o %t
+// RUN: %run %t | FileCheck %s
+
+#include <stdio.h>
+
+static void foo() {
+    printf("In foo.\n");
+}
+
+int main(int argc, char **argv) {
+  printf("One call.\n");
+  printf("Two calls.\n");
+  foo();
+  // CHECK: num_function_calls = 4
+  // CHECK: num_unknown_function_calls = 3
+  return 0;
+}