On 9/16/18 1:58 PM, Bernd Edlinger wrote:
> Hi,
>
> this is a cleanup of the recently added strlen/strcpy/stpcpy
> no nul warning code.
>
> Most importantly it moves the SSA_NAME handling from
> unterminated_array to string_constant, thereby fixing
> another round of xfails in the strlen and stpcpy test cases.
>
> I need to say that the fix for bug 86622 is relying in
> type info on the pointer which is probably not safe in
> GIMPLE in the light of the recent discussion.
>
> I had to add two further exceptions, which should
> be safe in general: that is a pointer arithmentic on a string
> literal is okay, and arithmetic on a string constant
> that is exactly the size of the whole DECL, cannot
> access an adjacent member.
>
>
> Bootstrapped and reg-tested on x86_64-pc-linux-gnu.
> Is it OK for trunk?
>
>
> Thanks
> Bernd.
>
>
> patch-cleanup-no-nul.diff
>
> gcc:
> 2018-09-16 Bernd Edlinger <bernd.edlin...@hotmail.de>
>
> * builtins.h (unterminated_array): Remove prototype.
> * builtins.c (unterminated_array): Simplify. Make static.
> (expand_builtin_strcpy_args): Don't use TREE_NO_WARNING here.
> (expand_builtin_stpcpy_1): Remove warn_string_no_nul without effect.
> * expr.c (string_constant): Handle SSA_NAME. Add more exceptions
> where pointer arithmetic is safe.
> * gimple-fold.c (get_range_strlen): Handle nonstr like in c_strlen.
> (get_max_strlen): Remove the unnecessary mynonstr handling.
> (gimple_fold_builtin_strcpy): Simplify.
> (gimple_fold_builtin_stpcpy): Simplify.
> (gimple_fold_builtin_sprintf): Remove NO_WARNING propagation
> without effect.
> (gimple_fold_builtin_strlen): Simplify.
>
> testsuite:
> 2018-09-16 Bernd Edlinger <bernd.edlin...@hotmail.de>
>
> * gcc.dg/warn-stpcpy-no-nul.c: Remove xfails.
> * gcc.dg/warn-strlen-no-nul.c: Remove xfails.
I extracted the unterminated_array simplifications and the changes to
string_constant and committed them to the trunk.
I left unterminated_array with external scope as a patch from Martin
wants to call it from outside builtins.c.
jeff
commit c1451dd20f9064084df7b45c4635c1bcb57a712d
Author: Jeff Law <l...@torsion.usersys.redhat.com>
Date: Mon Sep 17 14:09:55 2018 -0400
PR c/87387
* builtins.c (unterminated_array): Simplify.
* expr.c (string_constant): Handle SSA_NAME. Add more exceptions
where pointer arithmetic is safe.
* gcc.dg/warn-stpcpy-no-nul.c: Drop unnecessary xfails.
* gcc.dg/warn-stplen-no-nul.c: Likewise.
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 6be143e9f18..8ff607e4d23 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2018-09-25 Bernd Edlinger <bernd.edlin...@hotmail.de>
+
+ PR c/87387
+ * builtins.c (unterminated_array): Simplify.
+ * expr.c (string_constant): Handle SSA_NAME. Add more exceptions
+ where pointer arithmetic is safe.
+
2018-09-25 Richard Biener <rguent...@suse.de>
PR debug/83941
diff --git a/gcc/builtins.c b/gcc/builtins.c
index 1d4de099726..5f00208ff09 100644
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -570,28 +570,9 @@ warn_string_no_nul (location_t loc, const char *fn, tree
arg, tree decl)
tree
unterminated_array (tree exp)
{
- if (TREE_CODE (exp) == SSA_NAME)
- {
- gimple *stmt = SSA_NAME_DEF_STMT (exp);
- if (!is_gimple_assign (stmt))
- return NULL_TREE;
-
- tree rhs1 = gimple_assign_rhs1 (stmt);
- tree_code code = gimple_assign_rhs_code (stmt);
- 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;
- }
-
tree nonstr = NULL;
- if (c_strlen (exp, 1, &nonstr, 1) == NULL && nonstr)
- return nonstr;
-
- return NULL_TREE;
+ c_strlen (exp, 1, &nonstr);
+ return nonstr;
}
/* Compute the length of a null-terminated character string or wide
diff --git a/gcc/expr.c b/gcc/expr.c
index b8782b9b133..583c7f008ff 100644
--- a/gcc/expr.c
+++ b/gcc/expr.c
@@ -11372,7 +11372,10 @@ string_constant (tree arg, tree *ptr_offset, tree
*mem_size, tree *decl)
/* Avoid pointers to arrays (see bug 86622). */
if (POINTER_TYPE_P (TREE_TYPE (arg))
&& TREE_CODE (TREE_TYPE (TREE_TYPE (arg))) == ARRAY_TYPE
- && TREE_CODE (TREE_OPERAND (arg0, 0)) == ARRAY_REF)
+ && !(decl && !*decl)
+ && !(decl && tree_fits_uhwi_p (DECL_SIZE_UNIT (*decl))
+ && mem_size && tree_fits_uhwi_p (*mem_size)
+ && tree_int_cst_equal (*mem_size, DECL_SIZE_UNIT (*decl))))
return NULL_TREE;
tree type = TREE_TYPE (arg1);
@@ -11381,6 +11384,38 @@ string_constant (tree arg, tree *ptr_offset, tree
*mem_size, tree *decl)
}
return NULL_TREE;
}
+ else if (TREE_CODE (arg) == SSA_NAME)
+ {
+ gimple *stmt = SSA_NAME_DEF_STMT (arg);
+ if (!is_gimple_assign (stmt))
+ return NULL_TREE;
+
+ tree rhs1 = gimple_assign_rhs1 (stmt);
+ tree_code code = gimple_assign_rhs_code (stmt);
+ if (code == ADDR_EXPR)
+ return string_constant (rhs1, ptr_offset, mem_size, decl);
+ else if (code != POINTER_PLUS_EXPR)
+ return NULL_TREE;
+
+ tree offset;
+ if (tree str = string_constant (rhs1, &offset, mem_size, decl))
+ {
+ /* Avoid pointers to arrays (see bug 86622). */
+ if (POINTER_TYPE_P (TREE_TYPE (rhs1))
+ && TREE_CODE (TREE_TYPE (TREE_TYPE (rhs1))) == ARRAY_TYPE
+ && !(decl && !*decl)
+ && !(decl && tree_fits_uhwi_p (DECL_SIZE_UNIT (*decl))
+ && mem_size && tree_fits_uhwi_p (*mem_size)
+ && tree_int_cst_equal (*mem_size, DECL_SIZE_UNIT (*decl))))
+ return NULL_TREE;
+
+ tree rhs2 = gimple_assign_rhs2 (stmt);
+ tree type = TREE_TYPE (rhs2);
+ *ptr_offset = fold_build2 (PLUS_EXPR, type, offset, rhs2);
+ return str;
+ }
+ return NULL_TREE;
+ }
else if (DECL_P (arg))
array = arg;
else
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 05dbb0d40ea..7b26b894b15 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2018-09-25 Jeff Law <l...@redhat.com>
+
+ * gcc.dg/warn-stpcpy-no-nul.c: Drop unnecessary xfails.
+ * gcc.dg/warn-stplen-no-nul.c: Likewise.
+
2018-09-25 Alexandre Oliva <ol...@adacore.com>
* gnat.dg/dinst.adb: Adjust for locviews.
diff --git a/gcc/testsuite/gcc.dg/warn-stpcpy-no-nul.c
b/gcc/testsuite/gcc.dg/warn-stpcpy-no-nul.c
index 78c4a7f9286..e718010ec2a 100644
--- a/gcc/testsuite/gcc.dg/warn-stpcpy-no-nul.c
+++ b/gcc/testsuite/gcc.dg/warn-stpcpy-no-nul.c
@@ -71,13 +71,13 @@ void test_two_dim_array (char *d)
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[3][v0] + v1); /* { dg-warning "nul" } */
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 (&b[i3][v0] + v1); /* { dg-warning "nul" } */
T (v0 ? "" : b[0]);
T (v0 ? "" : b[1]);
diff --git a/gcc/testsuite/gcc.dg/warn-strlen-no-nul.c
b/gcc/testsuite/gcc.dg/warn-strlen-no-nul.c
index 997dfc3540f..b716aa44770 100644
--- a/gcc/testsuite/gcc.dg/warn-strlen-no-nul.c
+++ b/gcc/testsuite/gcc.dg/warn-strlen-no-nul.c
@@ -71,9 +71,9 @@ T (&b[3][v0] + v1); /* { dg-warning "nul" } */
T (&b[i3][i1]); /* { dg-warning "nul" } */
T (&b[i3][i1] + 1); /* { dg-warning "nul" } */
T (&b[i3][i1] + i1); /* { dg-warning "nul" } */
-T (&b[i3][v0]); /* { dg-warning "nul" "pr86919" { xfail *-*-* } } */
-T (&b[i3][i1] + v0); /* { dg-warning "nul" "pr86919" { xfail *-*-* } } */
-T (&b[i3][v0] + v1); /* { dg-warning "nul" "pr86919" { xfail *-*-* } } */
+T (&b[i3][v0]); /* { dg-warning "nul" } */
+T (&b[i3][i1] + v0); /* { dg-warning "nul" } */
+T (&b[i3][v0] + v1); /* { dg-warning "nul" } */
T (v0 ? "" : b[0]);
T (v0 ? "" : b[1]);
@@ -152,10 +152,10 @@ T (&s.b[1] + v0); /* { dg-warning "nul" } */
T (&s.b[i0]); /* { dg-warning "nul" } */
T (&s.b[i0] + i1); /* { dg-warning "nul" } */
-T (&s.b[i0] + v0); /* { dg-warning "nul" "pr86919" { xfail *-*-* } } */
+T (&s.b[i0] + v0); /* { dg-warning "nul" } */
T (&s.b[i1]); /* { dg-warning "nul" } */
T (&s.b[i1] + i1); /* { dg-warning "nul" } */
-T (&s.b[i1] + v0); /* { dg-warning "nul" "pr86919" { xfail *-*-* } } */
+T (&s.b[i1] + v0); /* { dg-warning "nul" } */
struct B { struct A a[2]; };
