Rewrite tool (#34)

* Initial version of the checked-c conversion tool. Current features:

 - Processes single C files or multiple C files (up to whole programs)
 - Infers "ptr-ness" for local variables used in those programs.
 - Re-write many source files
 - Supports many aspects of the C grammar
 - Contains unit tests

Current weaknesses:

 - Macro support is limited
 - Casting support is limited, needs structural type equality checks
 - No inherent support for standard library functions.
 - Doesn't honor existing checked C types

Author: Andrew Ruef

test/CheckedCRewriter/lit.local.cfg

@@ -0,0 +1 @@
+config.suffixes = ['.c']

test/CheckedCRewriter/simple_locals.c

@@ -0,0 +1,152 @@
+// Tests for Checked C rewriter tool.
+//
+// Checks very simple inference properties for local variables.
+//
+// RUN: checked-c-convert %s -- | FileCheck %s
+// RUN: checked-c-convert %s -- | %clang_cc1 -verify -fcheckedc-extension -x c -
+// expected-no-diagnostics
+
+void f1() {
+    int b = 0;
+    int *a = &b;
+    *a = 1;
+}
+// CHECK: void f1() {
+// CHECK-NEXT: int b = 0;
+// CHECK-NEXT: ptr<int> a = &b;
+
+void f2() {
+    char b = 'a';
+    char *a = &b;
+    *a = 'b';
+}
+//CHECK: void f2() {
+//CHECK-NEXT: char b = 'a';
+//CHECK-NEXT: ptr<char> a = &b;
+
+typedef struct _BarRec {
+  int a;
+  int b;
+  int c;
+  int *d;
+} BarRec;
+
+void upd(BarRec *P, int a) {
+  P->a = a;
+}
+//CHECK: void upd(ptr<BarRec> P, int a) {
+//CHECK-NEXT: P->a = a;
+//CHECK-NEXT: }
+
+void canthelp(int *a, int b, int c) {
+  *(a + b) = c;
+}
+//CHECK: void canthelp(int *a, int b, int c) {
+//CHECK-NEXT:  *(a + b) = c;
+//CHECK-NEXT: }
+
+void partialhelp(int *a, int b, int c) {
+  int *d = a;
+  *d = 0;
+  *(a + b) = c;
+}
+//CHECK: void partialhelp(int *a, int b, int c) {
+//CHECK-NEXT: ptr<int> d = a;
+//CHECK-NEXT: *d = 0;
+//CHECK-NEXT:  *(a + b) = c;
+//CHECK-NEXT: }
+
+void g(void) {
+    int a = 0, *b = &a;
+    *b = 1;
+}
+//CHECK: void g(void) {
+//CHECK-NEXT: int a = 0;
+//CHECK-NEXT: ptr<int> b = &a;
+
+void gg(void) {
+  int a = 0, *b = &a, **c = &b;
+
+  *b = 1;
+  **c = 2;
+}
+//CHECK: void gg(void) {
+//CHECK-NEXT: int a = 0;
+//CHECK-NEXT: ptr<int> b = &a;
+//CHECK-NEXT: ptr<ptr<int> > c = &b;
+
+#define ONE 1
+
+int goo(int *, int);
+//CHECK: int goo(ptr<int>, int);
+
+struct blah {
+  int a;
+  int b;
+  struct blah *c;
+};
+
+int bar(int, int);
+
+int foo(int a, int b) {
+  int tmp = a + ONE;
+  int *tmp2 = &tmp;
+  return tmp + b + *tmp2;
+}
+//CHECK: int foo(int a, int b) {
+//CHECK-NEXT: int tmp = a + ONE;
+//CHECK-NEXT: ptr<int> tmp2 = &tmp;
+//CHECK-NEXT: return tmp + b + *tmp2;
+//CHECK-NEXT: }
+
+int bar(int a, int b) {
+  return a + b;
+}
+//CHECK: int bar(int a, int b) {
+//CHECK-NEXT: return a + b;
+//CHECK-NEXT: }
+
+int baz(int *a, int b, int c) {
+  int tmp = b + c;
+  int *aa = a;
+  *aa = tmp;
+  return tmp;
+}
+//CHECK: int baz(ptr<int> a, int b, int c) {
+//CHECK-NEXT: int tmp = b + c;
+//CHECK-NEXT: ptr<int> aa = a;
+//CHECK-NEXT: *aa = tmp;
+//CHECK-NEXT: return tmp;
+
+int arrcheck(int *a, int b) {
+  return a[b];
+}
+//CHECK: int arrcheck(int *a, int b) {
+//CHECK-NEXT: return a[b];
+//CHECK-NEXT: }
+
+int badcall(int *a, int b) {
+  return arrcheck(a, b);
+}
+//CHECK: int badcall(int *a, int b) {
+//CHECK-NEXT: return arrcheck(a, b); 
+//CHECK-NEXT: }
+
+void pullit(char *base, char *out, int *index) {
+  char tmp = base[*index];
+  *out = tmp;
+  *index = *index + 1;
+
+  return;
+}
+//CHECK: void pullit(char* base, ptr<char> out, ptr<int> index) {
+
+void driver() {
+  char buf[10] = { 0 };
+  int index = 0;
+  char v;
+
+  pullit(buf, &v, &index);
+  pullit(buf, &v, &index);
+  pullit(buf, &v, &index);
+}

tools/CMakeLists.txt

@@ -5,6 +5,7 @@ add_clang_subdirectory(driver)
 add_clang_subdirectory(clang-format)
 add_clang_subdirectory(clang-format-vs)
 add_clang_subdirectory(clang-fuzzer)
+add_clang_subdirectory(checked-c-convert)
 
 add_clang_subdirectory(c-index-test)
 

tools/checked-c-convert/CMakeLists.txt

@@ -0,0 +1,28 @@
+set( LLVM_LINK_COMPONENTS
+  ${LLVM_TARGETS_TO_BUILD}
+  Option
+  Support
+  )
+
+add_clang_executable(checked-c-convert
+  CheckedCConvert.cpp
+  NewTyp.cpp
+  ProgramInfo.cpp
+  MappingVisitor.cpp
+  ConstraintBuilder.cpp
+  PersistentSourceLoc.cpp
+  Constraints.cpp
+  )
+
+target_link_libraries(checked-c-convert
+  clangAST
+  clangBasic
+  clangDriver
+  clangFrontend
+  clangRewriteFrontend
+  clangStaticAnalyzerFrontend
+  clangTooling
+  )
+
+install(TARGETS checked-c-convert
+  RUNTIME DESTINATION bin)