The attached changes implement the detection of past-the-end reads
by stpcpy due to unterminated arguments.
PR tree-optimization/86552 - missing warning for reading past the end of non-string arrays
gcc/ChangeLog:
* builtins.c (unterminated_array): Handle ARRAY_REF.
(expand_builtin_stpcpy_1): Detect unterminated char arrays.
* builtins.h (unterminated_array): Declare extern.
* gimple-fold.c (gimple_fold_builtin_stpcpy): Detect unterminated
arrays.
(gimple_fold_builtin_sprintf): Propagate NO_WARNING to transformed
calls.
gcc/testsuite/ChangeLog:
* gcc.dg/warn-stpcpy-no-nul.c: New test.
diff --git a/gcc/builtins.c b/gcc/builtins.c
index a77f25c..2f493d3 100644
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -584,7 +584,7 @@ warn_string_no_nul (location_t loc, tree exp, tree fndecl, tree nonstr)
the declaration of the object of which the array is a member or
element. Otherwise return null. */
-static tree
+tree
unterminated_array (tree exp)
{
if (TREE_CODE (exp) == SSA_NAME)
@@ -595,7 +595,10 @@ unterminated_array (tree exp)
tree rhs1 = gimple_assign_rhs1 (stmt);
tree_code code = gimple_assign_rhs_code (stmt);
- if (code != POINTER_PLUS_EXPR)
+ if (code == ADDR_EXPR
+ && TREE_CODE (TREE_OPERAND (rhs1, 0)) == ARRAY_REF)
+ rhs1 = rhs1;
+ else if (code != POINTER_PLUS_EXPR)
return NULL_TREE;
exp = rhs1;
@@ -4004,9 +4007,14 @@ expand_builtin_stpcpy_1 (tree exp, rtx target, machine_mode mode)
compile-time, not an expression containing a string. This is
because the latter will potentially produce pessimized code
when used to produce the return value. */
- if (! c_getstr (src) || ! (len = c_strlen (src, 0)))
+ tree nonstr = NULL_TREE;
+ if (!c_getstr (src, NULL, &nonstr)
+ || !(len = c_strlen (src, 0, &nonstr)))
return expand_movstr (dst, src, target, /*endp=*/2);
+ if (nonstr && !TREE_NO_WARNING (exp))
+ warn_string_no_nul (EXPR_LOCATION (exp), exp, NULL_TREE, nonstr);
+
lenp1 = size_binop_loc (loc, PLUS_EXPR, len, ssize_int (1));
ret = expand_builtin_mempcpy_args (dst, src, lenp1,
target, exp, /*endp=*/2);
diff --git a/gcc/builtins.h b/gcc/builtins.h
index 73b0b0b..f722dd8 100644
--- a/gcc/builtins.h
+++ b/gcc/builtins.h
@@ -103,6 +103,7 @@ extern bool target_char_cst_p (tree t, char *p);
extern internal_fn associated_internal_fn (tree);
extern internal_fn replacement_internal_fn (gcall *);
+extern tree unterminated_array (tree);
extern void warn_string_no_nul (location_t, tree, tree, tree);
extern tree max_object_size ();
diff --git a/gcc/gimple-fold.c b/gcc/gimple-fold.c
index 3fb8d85..70cb4ef 100644
--- a/gcc/gimple-fold.c
+++ b/gcc/gimple-fold.c
@@ -2787,7 +2787,7 @@ gimple_fold_builtin_stpcpy (gimple_stmt_iterator *gsi)
location_t loc = gimple_location (stmt);
tree dest = gimple_call_arg (stmt, 0);
tree src = gimple_call_arg (stmt, 1);
- tree fn, len, lenp1;
+ tree fn, lenp1;
/* If the result is unused, replace stpcpy with strcpy. */
if (gimple_call_lhs (stmt) == NULL_TREE)
@@ -2800,10 +2800,25 @@ gimple_fold_builtin_stpcpy (gimple_stmt_iterator *gsi)
return true;
}
- len = c_strlen (src, 1);
+ /* Set to non-null if ARG refers to an unterminated array. */
+ tree nonstr;
+ tree len = c_strlen (src, 1, &nonstr);
if (!len
|| TREE_CODE (len) != INTEGER_CST)
- return false;
+ {
+ nonstr = unterminated_array (src);
+ if (!nonstr)
+ return false;
+ }
+
+ if (nonstr)
+ {
+ /* Avoid folding calls with unterminated arrays. */
+ if (!gimple_no_warning_p (stmt))
+ warn_string_no_nul (loc, NULL_TREE, gimple_call_fndecl (stmt), nonstr);
+ gimple_set_no_warning (stmt, true);
+ return false;
+ }
if (optimize_function_for_size_p (cfun)
/* If length is zero it's small enough. */
@@ -3066,6 +3081,12 @@ gimple_fold_builtin_sprintf (gimple_stmt_iterator *gsi)
'format' is known to contain no % formats. */
gimple_seq stmts = NULL;
gimple *repl = gimple_build_call (fn, 2, dest, fmt);
+
+ /* Propagate the NO_WARNING bit to avoid issuing the same
+ warning more than once. */
+ if (gimple_no_warning_p (stmt))
+ gimple_set_no_warning (repl, true);
+
gimple_seq_add_stmt_without_update (&stmts, repl);
if (gimple_call_lhs (stmt))
{
@@ -3114,6 +3135,12 @@ gimple_fold_builtin_sprintf (gimple_stmt_iterator *gsi)
/* Convert sprintf (str1, "%s", str2) into strcpy (str1, str2). */
gimple_seq stmts = NULL;
gimple *repl = gimple_build_call (fn, 2, dest, orig);
+
+ /* Propagate the NO_WARNING bit to avoid issuing the same
+ warning more than once. */
+ if (gimple_no_warning_p (stmt))
+ gimple_set_no_warning (repl, true);
+
gimple_seq_add_stmt_without_update (&stmts, repl);
if (gimple_call_lhs (stmt))
{
diff --git a/gcc/testsuite/gcc.dg/warn-stpcpy-no-nul.c b/gcc/testsuite/gcc.dg/warn-stpcpy-no-nul.c
new file mode 100644
index 0000000..78c4a7f
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/warn-stpcpy-no-nul.c
@@ -0,0 +1,324 @@
+/* PR tree-optimization/86552 - missing warning for reading past the end
+ of non-string arrays
+ { dg-do compile }
+ { dg-options "-O2 -Wall -Wno-array-bounds -ftrack-macro-expansion=0" } */
+
+extern char* stpcpy (char*, const char*);
+
+const char a[5] = "12345"; /* { dg-message "declared here" } */
+
+int v0 = 0;
+int v1 = 1;
+int v2 = 1;
+int v3 = 1;
+
+void sink (char*, ...);
+
+#define T(str) sink (stpcpy (d, str))
+
+void test_one_dim_array (char *d)
+{
+ T (a); /* { dg-warning "argument missing terminating nul" } */
+ T (&a[0]); /* { dg-warning "nul" } */
+ T (&a[0] + 1); /* { dg-warning "nul" } */
+ T (&a[1]); /* { dg-warning "nul" } */
+
+ int i0 = 0;
+ int i1 = i0 + 1;
+
+ T (&a[i0]); /* { dg-warning "nul" } */
+ T (&a[i0] + 1); /* { dg-warning "nul" } */
+ T (&a[i1]); /* { dg-warning "nul" } */
+
+ T (&a[v0]); /* { dg-warning "nul" } */
+ T (&a[v0] + 1); /* { dg-warning "nul" } */
+ T (&a[v0] + v1); /* { dg-warning "nul" } */
+}
+
+const char b[][5] = { /* { dg-message "declared here" } */
+ "12", "123", "1234", "54321"
+};
+
+void test_two_dim_array (char *d)
+{
+ int i0 = 0;
+ int i1 = i0 + 1;
+ int i2 = i1 + 1;
+ int i3 = i2 + 1;
+
+ T (b[0]);
+ T (b[1]);
+ T (b[2]);
+ T (b[3]); /* { dg-warning "nul" } */
+ T (b[i0]);
+ T (b[i1]);
+ T (b[i2]);
+ T (b[i3]); /* { dg-warning "nul" } */
+ T (b[v0]);
+ T (b[v3]);
+
+ T (&b[2][1]);
+ T (&b[2][1] + 1);
+ T (&b[2][v0]);
+ T (&b[2][1] + v0);
+
+ T (&b[i2][i1]);
+ T (&b[i2][i1] + i1);
+ T (&b[i2][v0]);
+ T (&b[i2][i1] + v0);
+
+ T (&b[3][1]); /* { dg-warning "nul" } */
+ T (&b[3][1] + 1); /* { dg-warning "nul" } */
+ T (&b[3][v0]); /* { dg-warning "nul" } */
+ T (&b[3][1] + v0); /* { dg-warning "nul" } */
+ T (&b[3][v0] + v1); /* { dg-warning "nul" "bug ???" { xfail *-*-* } } */
+
+ T (&b[i3][i1]); /* { dg-warning "nul" } */
+ T (&b[i3][i1] + i1); /* { dg-warning "nul" } */
+ T (&b[i3][v0]); /* { dg-warning "nul" } */
+ T (&b[i3][i1] + v0); /* { dg-warning "nul" } */
+ T (&b[i3][v0] + v1); /* { dg-warning "nul" "bug ???" { xfail *-*-* } } */
+
+ T (v0 ? "" : b[0]);
+ T (v0 ? "" : b[1]);
+ T (v0 ? "" : b[2]);
+ T (v0 ? "" : b[3]); /* { dg-warning "nul" "bug ???" { xfail *-*-* } } */
+ T (v0 ? b[0] : "");
+ T (v0 ? b[1] : "");
+ T (v0 ? b[2] : "");
+ T (v0 ? b[3] : ""); /* { dg-warning "nul" "bug ???" { xfail *-*-* } } */
+
+ T (v0 ? "1234" : b[3]); /* { dg-warning "nul" "bug ???" { xfail *-*-* } } */
+ T (v0 ? b[3] : "1234"); /* { dg-warning "nul" "bug ???" { xfail *-*-* } } */
+
+ T (v0 ? a : b[3]); /* { dg-warning "nul" "bug ???" { xfail *-*-* } } */
+ T (v0 ? b[0] : b[2]);
+ T (v0 ? b[2] : b[3]); /* { dg-warning "nul" "bug ???" { xfail *-*-* } } */
+ T (v0 ? b[3] : b[2]); /* { dg-warning "nul" "bug ???" { xfail *-*-* } } */
+
+ T (v0 ? b[0] : &b[3][0] + 1); /* { dg-warning "nul" "bug ???" { xfail *-*-* } } */
+ T (v0 ? b[1] : &b[3][1] + v0); /* { dg-warning "nul" "bug ???" { xfail *-*-* } } */
+
+ /* It's possible to detect the missing nul in the following two
+ expressions but GCC doesn't do it yet. */
+ T (v0 ? &b[3][1] + v0 : b[2]); /* { dg-warning "nul" "bug ???" { xfail *-*-* } } */
+ T (v0 ? &b[3][v0] : &b[3][v1]); /* { dg-warning "nul" "bug ???" { xfail *-*-* } } */
+}
+
+struct A { char a[5], b[5]; };
+
+const struct A s = { "1234", "12345" };
+
+void test_struct_member (char *d)
+{
+ int i0 = 0;
+ int i1 = i0 + 1;
+
+ T (s.a);
+ T (&s.a[0]);
+ T (&s.a[0] + 1);
+ T (&s.a[0] + i0);
+ T (&s.a[1]);
+ T (&s.a[1] + 1);
+ T (&s.a[1] + i0);
+
+ T (&s.a[i0]);
+ T (&s.a[i0] + 1);
+ T (&s.a[i0] + v0);
+ T (&s.a[i1]);
+ T (&s.a[i1] + 1);
+ T (&s.a[i1] + v0);
+
+ T (s.a);
+ T (&s.a[0]);
+ T (&s.a[0] + 1);
+ T (&s.a[0] + v0);
+ T (&s.a[1]);
+ T (&s.a[1] + 1);
+ T (&s.a[1] + v0);
+
+ T (&s.a[i0]);
+ T (&s.a[i0] + 1);
+ T (&s.a[i0] + v0);
+ T (&s.a[i1]);
+ T (&s.a[i1] + 1);
+ T (&s.a[i1] + v0);
+
+ T (&s.a[v0]);
+ T (&s.a[v0] + 1);
+ T (&s.a[v0] + v0);
+ T (&s.a[v1]);
+ T (&s.a[v1] + 1);
+ T (&s.a[v1] + v0);
+
+ T (s.b); /* { dg-warning "nul" } */
+ T (&s.b[0]); /* { dg-warning "nul" } */
+ T (&s.b[0] + 1); /* { dg-warning "nul" } */
+ T (&s.b[0] + i0); /* { dg-warning "nul" } */
+ T (&s.b[1]); /* { dg-warning "nul" } */
+ T (&s.b[1] + 1); /* { dg-warning "nul" } */
+ T (&s.b[1] + i0); /* { dg-warning "nul" } */
+
+ T (s.b); /* { dg-warning "nul" } */
+ T (&s.b[0]); /* { dg-warning "nul" } */
+ T (&s.b[0] + 1); /* { dg-warning "nul" } */
+ T (&s.b[0] + v0); /* { dg-warning "nul" } */
+ T (&s.b[1]); /* { dg-warning "nul" } */
+ T (&s.b[1] + 1); /* { dg-warning "nul" } */
+ T (&s.b[1] + v0); /* { dg-warning "nul" } */
+
+ T (s.b); /* { dg-warning "nul" } */
+ T (&s.b[v0]); /* { dg-warning "nul" "bug ???" { xfail *-*-* } } */
+ T (&s.b[v0] + 1); /* { dg-warning "nul" "bug ???" { xfail *-*-* } } */
+ T (&s.b[v0] + v0); /* { dg-warning "nul" "bug ???" { xfail *-*-* } } */
+ T (&s.b[v1]); /* { dg-warning "nul" "bug ???" { xfail *-*-* } } */
+ T (&s.b[v1] + 1); /* { dg-warning "nul" "bug ???" { xfail *-*-* } } */
+ T (&s.b[v1] + v0); /* { dg-warning "nul" "bug ???" { xfail *-*-* } } */
+}
+
+struct B { struct A a[2]; };
+
+const struct B ba[] = {
+ { { { "123", "12345" }, { "12345", "123" } } },
+ { { { "12345", "123" }, { "123", "12345" } } },
+ { { { "1", "12" }, { "123", "1234" } } },
+ { { { "123", "1234" }, { "12345", "12" } } }
+};
+
+void test_array_of_structs (char *d)
+{
+ T (ba[0].a[0].a);
+ T (&ba[0].a[0].a[0]);
+ T (&ba[0].a[0].a[0] + 1);
+ T (&ba[0].a[0].a[0] + v0);
+ T (&ba[0].a[0].a[1]);
+ T (&ba[0].a[0].a[1] + 1);
+ T (&ba[0].a[0].a[1] + v0);
+
+ T (ba[0].a[0].b); /* { dg-warning "nul" } */
+ T (&ba[0].a[0].b[0]); /* { dg-warning "nul" } */
+ T (&ba[0].a[0].b[0] + 1); /* { dg-warning "nul" } */
+ T (&ba[0].a[0].b[0] + v0); /* { dg-warning "nul" } */
+ T (&ba[0].a[0].b[1]); /* { dg-warning "nul" } */
+ T (&ba[0].a[0].b[1] + 1); /* { dg-warning "nul" } */
+ T (&ba[0].a[0].b[1] + v0); /* { dg-warning "nul" } */
+
+ T (ba[0].a[1].a); /* { dg-warning "nul" } */
+ T (&ba[0].a[1].a[0]); /* { dg-warning "nul" } */
+ T (&ba[0].a[1].a[0] + 1); /* { dg-warning "nul" } */
+ T (&ba[0].a[1].a[0] + v0); /* { dg-warning "nul" } */
+ T (&ba[0].a[1].a[1]); /* { dg-warning "nul" } */
+ T (&ba[0].a[1].a[1] + 1); /* { dg-warning "nul" } */
+ T (&ba[0].a[1].a[1] + v0); /* { dg-warning "nul" } */
+
+ T (ba[0].a[1].b);
+ T (&ba[0].a[1].b[0]);
+ T (&ba[0].a[1].b[0] + 1);
+ T (&ba[0].a[1].b[0] + v0);
+ T (&ba[0].a[1].b[1]);
+ T (&ba[0].a[1].b[1] + 1);
+ T (&ba[0].a[1].b[1] + v0);
+
+
+ T (ba[1].a[0].a); /* { dg-warning "nul" } */
+ T (&ba[1].a[0].a[0]); /* { dg-warning "nul" } */
+ T (&ba[1].a[0].a[0] + 1); /* { dg-warning "nul" } */
+ T (&ba[1].a[0].a[0] + v0); /* { dg-warning "nul" } */
+ T (&ba[1].a[0].a[1]); /* { dg-warning "nul" } */
+ T (&ba[1].a[0].a[1] + 1); /* { dg-warning "nul" } */
+ T (&ba[1].a[0].a[1] + v0); /* { dg-warning "nul" } */
+
+ T (ba[1].a[0].b);
+ T (&ba[1].a[0].b[0]);
+ T (&ba[1].a[0].b[0] + 1);
+ T (&ba[1].a[0].b[0] + v0);
+ T (&ba[1].a[0].b[1]);
+ T (&ba[1].a[0].b[1] + 1);
+ T (&ba[1].a[0].b[1] + v0);
+
+ T (ba[1].a[1].a);
+ T (&ba[1].a[1].a[0]);
+ T (&ba[1].a[1].a[0] + 1);
+ T (&ba[1].a[1].a[0] + v0);
+ T (&ba[1].a[1].a[1]);
+ T (&ba[1].a[1].a[1] + 1);
+ T (&ba[1].a[1].a[1] + v0);
+
+ T (ba[1].a[1].b); /* { dg-warning "nul" } */
+ T (&ba[1].a[1].b[0]); /* { dg-warning "nul" } */
+ T (&ba[1].a[1].b[0] + 1); /* { dg-warning "nul" } */
+ T (&ba[1].a[1].b[0] + v0); /* { dg-warning "nul" } */
+ T (&ba[1].a[1].b[1]); /* { dg-warning "nul" } */
+ T (&ba[1].a[1].b[1] + 1); /* { dg-warning "nul" } */
+ T (&ba[1].a[1].b[1] + v0); /* { dg-warning "nul" } */
+
+
+ T (ba[2].a[0].a);
+ T (&ba[2].a[0].a[0]);
+ T (&ba[2].a[0].a[0] + 1);
+ T (&ba[2].a[0].a[0] + v0);
+ T (&ba[2].a[0].a[1]);
+ T (&ba[2].a[0].a[1] + 1);
+ T (&ba[2].a[0].a[1] + v0);
+
+ T (ba[2].a[0].b);
+ T (&ba[2].a[0].b[0]);
+ T (&ba[2].a[0].b[0] + 1);
+ T (&ba[2].a[0].b[0] + v0);
+ T (&ba[2].a[0].b[1]);
+ T (&ba[2].a[0].b[1] + 1);
+ T (&ba[2].a[0].b[1] + v0);
+
+ T (ba[2].a[1].a);
+ T (&ba[2].a[1].a[0]);
+ T (&ba[2].a[1].a[0] + 1);
+ T (&ba[2].a[1].a[0] + v0);
+ T (&ba[2].a[1].a[1]);
+ T (&ba[2].a[1].a[1] + 1);
+ T (&ba[2].a[1].a[1] + v0);
+
+
+ T (ba[3].a[0].a);
+ T (&ba[3].a[0].a[0]);
+ T (&ba[3].a[0].a[0] + 1);
+ T (&ba[3].a[0].a[0] + v0);
+ T (&ba[3].a[0].a[1]);
+ T (&ba[3].a[0].a[1] + 1);
+ T (&ba[3].a[0].a[1] + v0);
+
+ T (ba[3].a[0].b);
+ T (&ba[3].a[0].b[0]);
+ T (&ba[3].a[0].b[0] + 1);
+ T (&ba[3].a[0].b[0] + v0);
+ T (&ba[3].a[0].b[1]);
+ T (&ba[3].a[0].b[1] + 1);
+ T (&ba[3].a[0].b[1] + v0);
+
+ T (ba[3].a[1].a); /* { dg-warning "nul" } */
+ T (&ba[3].a[1].a[0]); /* { dg-warning "nul" } */
+ T (&ba[3].a[1].a[0] + 1); /* { dg-warning "nul" } */
+ T (&ba[3].a[1].a[0] + v0); /* { dg-warning "nul" } */
+ T (&ba[3].a[1].a[1]); /* { dg-warning "nul" } */
+ T (&ba[3].a[1].a[1] + 1); /* { dg-warning "nul" } */
+ T (&ba[3].a[1].a[1] + v0); /* { dg-warning "nul" } */
+
+ T (ba[3].a[1].b);
+ T (&ba[3].a[1].b[0]);
+ T (&ba[3].a[1].b[0] + 1);
+ T (&ba[3].a[1].b[0] + v0);
+ T (&ba[3].a[1].b[1]);
+ T (&ba[3].a[1].b[1] + 1);
+ T (&ba[3].a[1].b[1] + v0);
+
+
+ T (v0 ? ba[0].a[0].a : ba[0].a[0].b); /* { dg-warning "nul" "bug ???" { xfail *-*-* } } */
+ T (v0 ? ba[0].a[0].a : ba[0].a[0].b); /* { dg-warning "nul" "bug ???" { xfail *-*-* } } */
+
+ T (v0 ? &ba[0].a[0].a[0] : &ba[3].a[1].a[0]); /* { dg-warning "nul" "bug ???" { xfail *-*-* } } */
+ T (v0 ? &ba[3].a[1].a[1] : ba[0].a[0].a); /* { dg-warning "nul" "bug ???" { xfail *-*-* } } */
+
+ T (v0 ? ba[0].a[0].a : ba[0].a[1].b);
+ T (v0 ? ba[0].a[1].b : ba[0].a[0].a);
+}
+
+/* { dg-prune-output " reading \[1-9\]\[0-9\]? bytes from a region " } */
