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[PATCH] PR middle-end/67220: GCC fails to properly handle libcall symbol visibility of built functions
- From: "H.J. Lu" <hongjiu dot lu at intel dot com>
- To: gcc-patches at gcc dot gnu dot org
- Date: Wed, 14 Oct 2015 09:21:46 -0700
- Subject: [PATCH] PR middle-end/67220: GCC fails to properly handle libcall symbol visibility of built functions
- Authentication-results: sourceware.org; auth=none
- Reply-to: "H.J. Lu" <hjl dot tools at gmail dot com>
By default, there is no visibility on builtin functions. When there is
explicitly declared visibility on the C library function which a builtin
function fall back on, we should honor the explicit visibility on the
the C library function.
There are 2 issues:
1. We never update visibility of the fall back C library function.
2. init_block_move_fn and init_block_clear_fn used to implement builtin
memcpy and memset generate the library call to memcpy and memset
directly without checking if there is explicitly declared visibility on
them.
This patch updates builtin function with explicit visibility and checks
visibility on builtin memcpy/memset when generating library call.
Tested on Linux/x86-64 without regressions. OK for trunk?
H.J.
---
gcc/c/
PR middle-end/67220
* c-decl.c (diagnose_mismatched_decls): Copy explicit visibility
to builtin function.
gcc/
PR middle-end/67220
* expr.c (init_block_move_fn): Copy visibility from the builtin
memcpy.
(init_block_clear_fn): Copy visibility from the builtin memset.
gcc/testsuite/
PR middle-end/67220
* gcc.target/i386/pr67220-1.c: New test.
* gcc.target/i386/pr67220-2.c: Likewise.
* gcc.target/i386/pr67220-3.c: Likewise.
* gcc.target/i386/pr67220-4.c: Likewise.
* gcc.target/i386/pr67220-5.c: Likewise.
* gcc.target/i386/pr67220-6.c: Likewise.
---
gcc/c/c-decl.c | 21 +++++++++++++++++----
gcc/expr.c | 12 ++++++++++--
gcc/testsuite/gcc.target/i386/pr67220-1.c | 15 +++++++++++++++
gcc/testsuite/gcc.target/i386/pr67220-2.c | 15 +++++++++++++++
gcc/testsuite/gcc.target/i386/pr67220-3.c | 15 +++++++++++++++
gcc/testsuite/gcc.target/i386/pr67220-4.c | 15 +++++++++++++++
gcc/testsuite/gcc.target/i386/pr67220-5.c | 14 ++++++++++++++
gcc/testsuite/gcc.target/i386/pr67220-6.c | 14 ++++++++++++++
8 files changed, 115 insertions(+), 6 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/i386/pr67220-1.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr67220-2.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr67220-3.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr67220-4.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr67220-5.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr67220-6.c
diff --git a/gcc/c/c-decl.c b/gcc/c/c-decl.c
index ce8406a..26460eb 100644
--- a/gcc/c/c-decl.c
+++ b/gcc/c/c-decl.c
@@ -2232,11 +2232,24 @@ diagnose_mismatched_decls (tree newdecl, tree olddecl,
/* warnings */
/* All decls must agree on a visibility. */
if (CODE_CONTAINS_STRUCT (TREE_CODE (newdecl), TS_DECL_WITH_VIS)
- && DECL_VISIBILITY_SPECIFIED (newdecl) && DECL_VISIBILITY_SPECIFIED (olddecl)
- && DECL_VISIBILITY (newdecl) != DECL_VISIBILITY (olddecl))
+ && DECL_VISIBILITY_SPECIFIED (newdecl))
{
- warned |= warning (0, "redeclaration of %q+D with different visibility "
- "(old visibility preserved)", newdecl);
+ if (DECL_VISIBILITY_SPECIFIED (olddecl))
+ {
+ if (DECL_VISIBILITY (newdecl) != DECL_VISIBILITY (olddecl))
+ warned |= warning (0, "redeclaration of %q+D with different "
+ "visibility (old visibility preserved)",
+ newdecl);
+ }
+ else if (TREE_CODE (olddecl) == FUNCTION_DECL
+ && DECL_BUILT_IN (olddecl))
+ {
+ enum built_in_function fncode = DECL_FUNCTION_CODE (olddecl);
+ tree fndecl = builtin_decl_explicit (fncode);
+ gcc_assert (fndecl && !DECL_VISIBILITY_SPECIFIED (fndecl));
+ DECL_VISIBILITY (fndecl) = DECL_VISIBILITY (newdecl);
+ DECL_VISIBILITY_SPECIFIED (fndecl) = 1;
+ }
}
if (TREE_CODE (newdecl) == FUNCTION_DECL)
diff --git a/gcc/expr.c b/gcc/expr.c
index 595324d..a12db96 100644
--- a/gcc/expr.c
+++ b/gcc/expr.c
@@ -1390,7 +1390,11 @@ init_block_move_fn (const char *asmspec)
TREE_PUBLIC (fn) = 1;
DECL_ARTIFICIAL (fn) = 1;
TREE_NOTHROW (fn) = 1;
- DECL_VISIBILITY (fn) = VISIBILITY_DEFAULT;
+ tree fndecl = builtin_decl_explicit (BUILT_IN_MEMCPY);
+ if (fndecl)
+ DECL_VISIBILITY (fn) = DECL_VISIBILITY (fndecl);
+ else
+ DECL_VISIBILITY (fn) = VISIBILITY_DEFAULT;
DECL_VISIBILITY_SPECIFIED (fn) = 1;
attr_args = build_tree_list (NULL_TREE, build_string (1, "1"));
@@ -2846,7 +2850,11 @@ init_block_clear_fn (const char *asmspec)
TREE_PUBLIC (fn) = 1;
DECL_ARTIFICIAL (fn) = 1;
TREE_NOTHROW (fn) = 1;
- DECL_VISIBILITY (fn) = VISIBILITY_DEFAULT;
+ tree fndecl = builtin_decl_explicit (BUILT_IN_MEMSET);
+ if (fndecl)
+ DECL_VISIBILITY (fn) = DECL_VISIBILITY (fndecl);
+ else
+ DECL_VISIBILITY (fn) = VISIBILITY_DEFAULT;
DECL_VISIBILITY_SPECIFIED (fn) = 1;
block_clear_fn = fn;
diff --git a/gcc/testsuite/gcc.target/i386/pr67220-1.c b/gcc/testsuite/gcc.target/i386/pr67220-1.c
new file mode 100644
index 0000000..06af0ed
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr67220-1.c
@@ -0,0 +1,15 @@
+/* { dg-do compile { target fpic } } */
+/* { dg-options "-O2 -fPIC" } */
+
+typedef __SIZE_TYPE__ size_t;
+extern void *memcpy (void *, const void *, size_t);
+extern void *memcpy (void *, const void *, size_t)
+ __attribute__ ((visibility ("hidden")));
+
+void
+bar (void *d, void *s, size_t n)
+{
+ memcpy (d, s, n);
+}
+
+/* { dg-final { scan-assembler-not "memcpy@PLT" } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr67220-2.c b/gcc/testsuite/gcc.target/i386/pr67220-2.c
new file mode 100644
index 0000000..71e1d1e
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr67220-2.c
@@ -0,0 +1,15 @@
+/* { dg-do compile { target fpic } } */
+/* { dg-options "-O2 -fPIC" } */
+
+typedef __SIZE_TYPE__ size_t;
+extern void *memset (void *, int, size_t);
+extern void *memset (void *, int, size_t)
+ __attribute__ ((visibility ("hidden")));
+
+void
+bar (void *s, size_t n)
+{
+ memset (s, '\0', n);
+}
+
+/* { dg-final { scan-assembler-not "memset@PLT" } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr67220-3.c b/gcc/testsuite/gcc.target/i386/pr67220-3.c
new file mode 100644
index 0000000..fa54530
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr67220-3.c
@@ -0,0 +1,15 @@
+/* { dg-do compile { target fpic } } */
+/* { dg-options "-O2 -fPIC" } */
+
+typedef __SIZE_TYPE__ size_t;
+extern void *memcpy (void *, const void *, size_t)
+ __attribute__ ((visibility ("hidden")));
+extern void *memcpy (void *, const void *, size_t);
+
+void
+bar (void *d, void *s, size_t n)
+{
+ __builtin_memcpy (d, s, n);
+}
+
+/* { dg-final { scan-assembler-not "memcpy@PLT" } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr67220-4.c b/gcc/testsuite/gcc.target/i386/pr67220-4.c
new file mode 100644
index 0000000..9ce02f4
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr67220-4.c
@@ -0,0 +1,15 @@
+/* { dg-do compile { target fpic } } */
+/* { dg-options "-O2 -fPIC" } */
+
+typedef __SIZE_TYPE__ size_t;
+extern void *memset (void *, int, size_t)
+ __attribute__ ((visibility ("hidden")));
+extern void *memset (void *, int, size_t);
+
+void
+bar (void *s, size_t n)
+{
+ __builtin_memset (s, '\0', n);
+}
+
+/* { dg-final { scan-assembler-not "memset@PLT" } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr67220-5.c b/gcc/testsuite/gcc.target/i386/pr67220-5.c
new file mode 100644
index 0000000..e2c8ba3
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr67220-5.c
@@ -0,0 +1,14 @@
+/* { dg-do compile { target fpic } } */
+/* { dg-options "-O2 -fPIC" } */
+
+extern int strcmp (const char *, const char *);
+extern int strcmp (const char *, const char *)
+ __attribute__ ((visibility ("hidden")));
+
+int
+bar (const char *d, const char *s)
+{
+ return __builtin_strcmp (d, s);
+}
+
+/* { dg-final { scan-assembler-not "strcmp@PLT" } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr67220-6.c b/gcc/testsuite/gcc.target/i386/pr67220-6.c
new file mode 100644
index 0000000..c83d4c2
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr67220-6.c
@@ -0,0 +1,14 @@
+/* { dg-do compile { target fpic } } */
+/* { dg-options "-O2 -fPIC" } */
+
+extern int strcmp (const char *, const char *)
+ __attribute__ ((visibility ("hidden")));
+extern int strcmp (const char *, const char *);
+
+int
+bar (const char *d, const char *s)
+{
+ return __builtin_strcmp (d, s);
+}
+
+/* { dg-final { scan-assembler-not "strcmp@PLT" } } */
--
2.4.3