add noexec stack note and relevant tests; fixes #21 and #22

templates/stack_alignment_check.s.jinja

@@ -1,6 +1,6 @@
 {# macros #}
 {% set arg_operands=["%edi", "%esi", "%edx", "%ecx", "%r8d", "%r9d", "16(%rbp)", "24(%rbp)"] %}
-{% macro alignment_check(fn_name, arg_count) %}
+{% macro alignment_check(fn_name, arg_count) -%}
     {% set fn_label=id_prefix~fn_name %}
     .globl {{fn_label}}
 {{fn_label}}:
@@ -30,9 +30,10 @@
     call    {{id_prefix}}exit{{plt_suffix}}
     popq    %rbp
     retq
-{% endmacro %}
+{%- endmacro %}
 {# actual program starts here #}
     # generated from templates/{{ self._TemplateReference__context.name }}
     .text
 {{alignment_check("even_arguments", 8)}}
-{{alignment_check("odd_arguments", 7)}}
+{{alignment_check("odd_arguments", 7)}}
+{{execstack_note}}

test_framework/test_tests/test_programs.py

@@ -66,6 +66,14 @@ def compile_and_run_sanitized(self, source_file: Path) -> None:
             "-O3",
             "-fsanitize=undefined",
         ]
+        if not basic.IS_OSX:
+            subproc_args.extend(
+                [
+                    # Linux only: executable stack should produce linker error (this catches missing execstack note in assembly test files)
+                    "-Xlinker",
+                    "--error-execstack",
+                ]
+            )
         subproc_args.extend(build_compiler_args(source_file))
 
         # compile it

tests/chapter_12/valid/type_specifiers/unsigned_type_specifiers.c

@@ -30,7 +30,8 @@ int main(void) {
     }
 
     /* use unsigned type specifier in for loop
-     * we'll iterate through this loop 11 times before dropping below 0 and wrapping around
+     * we'll iterate through this loop 11 times before dropping below 0 and
+     * wrapping around
      */
     int counter = 0;
     for (unsigned int index = 10; index < 4294967295U; index = index - 1) {
@@ -43,4 +44,3 @@ int main(void) {
 
     return 0;
 }
-

tests/chapter_15/valid/initialization/automatic_nested.c

@@ -2,7 +2,7 @@
 
 /* A fully initialized array of constants */
 int test_simple(void) {
-    int arr[3][3] = { { 1, 2, 3 }, { 4, 5, 6 }, { 7, 8, 9 } };
+    int arr[3][3] = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};
 
     // check the value of each element
     for (int i = 0; i < 3; i = i + 1) {
@@ -13,28 +13,27 @@ int test_simple(void) {
         }
     }
 
-    return 1; // success
+    return 1;  // success
 }
 
 /* A partially initialized array of constants.
  * Elements that aren't explicitly initialized
  * (including nested arrays) should be zeroed out.
  * */
 int test_partial(void) {
-
     // explicitly initialize only the first half of each array,
     // at each dimension
     int first_half_only[4][2][6] = {
-        {{1, 2, 3}},
-        {{4, 5, 6}}
+        {{1, 2, 3}},  // first_half_only[0][0][0-2]
+        {{4, 5, 6}}   // first_half_only[1][0][0-2]
     };
 
     int expected = 1;
     for (int i = 0; i < 4; i = i + 1) {
         for (int j = 0; j < 2; j = j + 1) {
             for (int k = 0; k < 6; k = k + 1) {
                 int val = first_half_only[i][j][k];
-                if (i > 1 || j > 0 || k > 2 ) {
+                if (i > 1 || j > 0 || k > 2) {
                     // this wasn't explicitly initialized, should be zero
                     if (val) {
                         return 0;
@@ -49,15 +48,13 @@ int test_partial(void) {
         }
     }
 
-    return 1; // success
+    return 1;  // success
 }
 
-
 /* elements in a compound initializer may include non-constant expressions
  * and expressions of other types, which are converted to the right type
  * as if by assignment */
 int test_non_constant_and_type_conversion(void) {
-
     // first let's define some value (that can't be copy propagated
     // or constant-folded away in Part III)
     extern unsigned int three(void);
@@ -66,8 +63,8 @@ int test_non_constant_and_type_conversion(void) {
     int *ptr = &negative_four;
 
     double arr[3][2] = {
-        { x, x / *ptr },
-        { three() }
+        {x, x / *ptr},
+        {three()},
     };
 
     if (arr[0][0] != 2000.0 || arr[0][1] != -500.0 || arr[1][0] != 3.0) {
@@ -78,7 +75,7 @@ int test_non_constant_and_type_conversion(void) {
         return 0;
     }
 
-    return 1; // success
+    return 1;  // success
 }
 
 // helper function for previous test
@@ -89,20 +86,18 @@ unsigned int three(void) {
 /* Initializing an array must not corrupt other objects on the stack. */
 long one = 1l;
 int test_preserve_stack(void) {
-
     int i = -1;
 
     /* Initialize with expressions of long type - make sure they're truncated
      * before being copied into the array.
      * Also use an array of < 16 bytes so it's not 16-byte aligned, so there are
      * eightbytes that include both array elements and other values.
-     * Also leave last element uninitialized; in assembly, we should set it to zero without
-     * overwriting what follows
+     * Also leave last element uninitialized; in assembly, we should set it to
+     * zero without overwriting what follows
      */
-    int arr[3][1] = { {one * 2l}, {one + three()} };
+    int arr[3][1] = {{one * 2l}, {one + three()}};
     unsigned int u = 2684366905;
 
-
     if (i != -1) {
         return 0;
     }
@@ -111,11 +106,11 @@ int test_preserve_stack(void) {
         return 0;
     }
 
-    if ( arr[0][0] != 2 || arr[1][0] != 4 || arr[2][0] != 0 ) {
+    if (arr[0][0] != 2 || arr[1][0] != 4 || arr[2][0] != 0) {
         return 0;
     }
 
-    return 1; // success
+    return 1;  // success
 }
 
 int main(void) {
@@ -135,6 +130,5 @@ int main(void) {
         return 4;
     }
 
-    return 0; // success
+    return 0;  // success
 }
-

tests/chapter_4/valid/multi_short_circuit.c

@@ -1,5 +1,7 @@
 #ifdef SUPPRESS_WARNINGS
-#ifndef __clang__
+#ifdef __clang__
+#pragma clang diagnostic ignored "-Wlogical-op-parentheses"
+#else
 #pragma GCC diagnostic ignored "-Wparentheses"
 #endif
 #endif

tests/chapter_4/valid/precedence.c

@@ -1,6 +1,7 @@
 #ifdef SUPPRESS_WARNINGS
 #ifdef __clang__
 #pragma clang diagnostic ignored "-Wconstant-logical-operand"
+#pragma clang diagnostic ignored "-Wlogical-op-parentheses"
 #else
 #pragma GCC diagnostic ignored "-Wparentheses"
 #endif

tests/chapter_9/valid/stack_arguments/stack_alignment_check_linux.s

@@ -40,7 +40,6 @@ even_arguments:
     call    exit@PLT
     popq    %rbp
     retq
-
     .globl odd_arguments
 odd_arguments:
     pushq   %rbp
@@ -79,3 +78,4 @@ odd_arguments:
     call    exit@PLT
     popq    %rbp
     retq
+	.section	".note.GNU-stack","",@progbits

tests/chapter_9/valid/stack_arguments/stack_alignment_check_osx.s

@@ -40,7 +40,6 @@ Lfail_even_arguments:
     call    _exit
     popq    %rbp
     retq
-
     .globl _odd_arguments
 _odd_arguments:
     pushq   %rbp