Re: [PATCH] libgccjit: Add support for types used by atomic builtins [PR96066] [PR96067]

[Antoni Boucher <bouanto@zoho.com>]

[-- Attachment #1: Type: text/plain, Size: 5153 bytes --]

Thanks for the review!
I updated the patch.

See notes below.

Le samedi 20 novembre 2021 à 13:50 -0500, David Malcolm a écrit :
> On Sat, 2021-11-20 at 11:27 -0500, Antoni Boucher wrote:
> > Hi.
> > Here's the updated patch.
> > Thanks for the review!
> 
> Thanks for the updated patch...
> 
> > 
> > Le jeudi 20 mai 2021 à 16:24 -0400, David Malcolm a écrit :
> > > On Mon, 2021-05-17 at 21:02 -0400, Antoni Boucher via Jit wrote:
> > > > Hello.
> > > > This patch fixes the issue with using atomic builtins in
> > > > libgccjit.
> > > > Thanks to review it.
> > > 
> > > [...snip...]
> > >  
> > > > diff --git a/gcc/jit/jit-recording.c b/gcc/jit/jit-recording.c
> > > > index 117ff70114c..de876ff9fa6 100644
> > > > --- a/gcc/jit/jit-recording.c
> > > > +++ b/gcc/jit/jit-recording.c
> > > > @@ -2598,8 +2598,18 @@
> > > > recording::memento_of_get_pointer::accepts_writes_from (type
> > > > *rtype)
> > > >      return false;
> > > >  
> > > >    /* It's OK to assign to a (const T *) from a (T *).  */
> > > > -  return m_other_type->unqualified ()
> > > > -    ->accepts_writes_from (rtype_points_to);
> > > > +  if (m_other_type->unqualified ()
> > > > +    ->accepts_writes_from (rtype_points_to)) {
> > > > +      return true;
> > > > +  }
> > > > +
> > > > +  /* It's OK to assign to a (volatile const T *) from a
> > > > (volatile
> > > > const T *). */
> > > > +  if (m_other_type->unqualified ()->unqualified ()
> > > > +    ->accepts_writes_from (rtype_points_to->unqualified ())) {
> > > > +      return true;
> > > > +  }
> > > 
> > > Presumably you need this to get the atomic builtins working?
> > > 
> > > If I'm reading the above correctly, the new test doesn't
> > > distinguish
> > > between the 3 different kinds of qualifiers (aligned, volatile,
> > > and
> > > const), it merely tries to strip some of them off.
> > > 
> > > It's not valid to e.g. assign to a (aligned T *) from a (const T
> > > *).
> > > 
> > > Maybe we need an internal enum to discriminate between different
> > > subclasses of decorated_type?
> 
> I'm still concerned about this case, my reading of the updated patch
> is
> that this case is still not quite correctly handled (see notes
> below).
> I don't think we currently have test coverage for assignment to e.g.
> (aligned T *) from a (const T*); I feel that it should be an error,
> without an explicit cast.
> 
> Please can you add a testcase for this?

Done.

> 
> If you want to go the extra mile, given that this is code created
> through an API, you could have a testcase that iterates through all
> possible combinations of qualifiers (for both source and destination
> pointer), and verifies that libgccjit at least doesn't crash on them
> (and hopefully does the right thing on each one)  :/
> 
> (perhaps doing each one in a different gcc_jit_context)
> 
> Might be nice to update test-fuzzer.c for the new qualifiers; I don't
> think I've touched it in a long time.

Done.

> 
> [...snip...]
> 
> > diff --git a/gcc/jit/jit-recording.h b/gcc/jit/jit-recording.h
> > index 4a994fe7094..60aaba2a246 100644
> > --- a/gcc/jit/jit-recording.h
> > +++ b/gcc/jit/jit-recording.h
> > @@ -545,6 +545,8 @@ public:
> >    virtual bool is_float () const = 0;
> >    virtual bool is_bool () const = 0;
> >    virtual type *is_pointer () = 0;
> > +  virtual type *is_volatile () { return NULL; }
> > +  virtual type *is_const () { return NULL; }
> >    virtual type *is_array () = 0;
> >    virtual struct_ *is_struct () { return NULL; }
> >    virtual bool is_void () const { return false; }
> > @@ -687,6 +689,13 @@ public:
> >    /* Strip off the "const", giving the underlying type.  */
> >    type *unqualified () FINAL OVERRIDE { return m_other_type; }
> >  
> > +  virtual bool is_same_type_as (type *other)
> > +  {
> > +    return m_other_type->is_same_type_as (other->is_const ());
> > +  }
> 
> What happens if other_is_const () returns NULL, and
>   m_other_type->is_same_type_as ()
> tries to call a vfunc on it...

Fixed.

> 
> > +
> > +  virtual type *is_const () { return m_other_type; }
> > +
> >    void replay_into (replayer *) FINAL OVERRIDE;
> >  
> >  private:
> > @@ -701,9 +710,16 @@ public:
> >    memento_of_get_volatile (type *other_type)
> >    : decorated_type (other_type) {}
> >  
> > +  virtual bool is_same_type_as (type *other)
> > +  {
> > +    return m_other_type->is_same_type_as (other->is_volatile ());
> > +  }
> 
> ...with similar considerations here.
> 
> i.e. is it possible for the user to create combinations of qualifiers
> that lead to a vfunc call with NULL "this" (and thus a segfault?)
> 
> > +
> >    /* Strip off the "volatile", giving the underlying type.  */
> >    type *unqualified () FINAL OVERRIDE { return m_other_type; }
> >  
> > +  virtual type *is_volatile () { return m_other_type; }
> > +
> >    void replay_into (replayer *) FINAL OVERRIDE;
> >  
> 
> Hope this is constructive
> Dave
> 


[-- Attachment #2: 0001-libgccjit-Add-support-for-types-used-by-atomic-built.patch --]
[-- Type: text/x-patch, Size: 11237 bytes --]

From b2d78a2edc1cd8b24ff88f0da608a69f1dff8229 Mon Sep 17 00:00:00 2001
From: Antoni Boucher <bouanto@zoho.com>
Date: Sun, 9 May 2021 20:14:37 -0400
Subject: [PATCH] libgccjit: Add support for types used by atomic builtins
 [PR96066] [PR96067]

2021-11-20  Antoni Boucher  <bouanto@zoho.com>

    gcc/jit/
            PR target/PR96066
            PR target/PR96067
            * jit-builtins.c: Implement missing types for builtins.
            * jit-recording.c:: Allow sending a volatile const void * as
            argument.
            * jit-recording.h: New functions (is_volatile, is_const) and
              allow comparing qualified types.
    gcc/testsuite/
            PR target/PR96066
            PR target/PR96067
            * jit.dg/all-non-failing-tests.h: Add test-builtin-types.c.
            * jit.dg/test-builtin-types.c
            * jit.dg/test-error-bad-assignment.c
            * jit.dg/test-fuzzer.c: Add fuzzing for type qualifiers.

Signed-off-by: Antoni Boucher <bouanto@zoho.com>
---
 gcc/jit/jit-builtins.c                        | 10 +--
 gcc/jit/jit-recording.c                       |  9 ++-
 gcc/jit/jit-recording.h                       | 20 +++++
 gcc/testsuite/jit.dg/all-non-failing-tests.h  | 10 +++
 gcc/testsuite/jit.dg/test-builtin-types.c     | 43 ++++++++++
 .../jit.dg/test-error-bad-assignment.c        | 78 +++++++++++++++++++
 gcc/testsuite/jit.dg/test-fuzzer.c            |  8 +-
 7 files changed, 170 insertions(+), 8 deletions(-)
 create mode 100644 gcc/testsuite/jit.dg/test-builtin-types.c
 create mode 100644 gcc/testsuite/jit.dg/test-error-bad-assignment.c

diff --git a/gcc/jit/jit-builtins.c b/gcc/jit/jit-builtins.c
index 1ea96f4e025..c279dd858f9 100644
--- a/gcc/jit/jit-builtins.c
+++ b/gcc/jit/jit-builtins.c
@@ -541,11 +541,11 @@ builtins_manager::make_primitive_type (enum jit_builtin_type type_id)
     // case BT_DFLOAT128:
     // case BT_VALIST_REF:
     // case BT_VALIST_ARG:
-    // case BT_I1:
-    // case BT_I2:
-    // case BT_I4:
-    // case BT_I8:
-    // case BT_I16:
+    case BT_I1: return m_ctxt->get_int_type (1, true);
+    case BT_I2: return m_ctxt->get_int_type (2, true);
+    case BT_I4: return m_ctxt->get_int_type (4, true);
+    case BT_I8: return m_ctxt->get_int_type (8, true);
+    case BT_I16: return m_ctxt->get_int_type (16, true);
     // case BT_PTR_CONST_STRING:
     }
 }
diff --git a/gcc/jit/jit-recording.c b/gcc/jit/jit-recording.c
index 117ff70114c..2eecf44c8db 100644
--- a/gcc/jit/jit-recording.c
+++ b/gcc/jit/jit-recording.c
@@ -2598,8 +2598,13 @@ recording::memento_of_get_pointer::accepts_writes_from (type *rtype)
     return false;
 
   /* It's OK to assign to a (const T *) from a (T *).  */
-  return m_other_type->unqualified ()
-    ->accepts_writes_from (rtype_points_to);
+  if (m_other_type->unqualified ()->accepts_writes_from (rtype_points_to))
+  {
+    return true;
+  }
+
+  /* It's OK to assign to a (volatile const T *) from a (volatile const T *). */
+  return m_other_type->is_same_type_as (rtype_points_to);
 }
 
 /* Implementation of pure virtual hook recording::memento::replay_into
diff --git a/gcc/jit/jit-recording.h b/gcc/jit/jit-recording.h
index 4a994fe7094..3163ff6748e 100644
--- a/gcc/jit/jit-recording.h
+++ b/gcc/jit/jit-recording.h
@@ -545,6 +545,8 @@ public:
   virtual bool is_float () const = 0;
   virtual bool is_bool () const = 0;
   virtual type *is_pointer () = 0;
+  virtual type *is_volatile () { return NULL; }
+  virtual type *is_const () { return NULL; }
   virtual type *is_array () = 0;
   virtual struct_ *is_struct () { return NULL; }
   virtual bool is_void () const { return false; }
@@ -687,6 +689,15 @@ public:
   /* Strip off the "const", giving the underlying type.  */
   type *unqualified () FINAL OVERRIDE { return m_other_type; }
 
+  virtual bool is_same_type_as (type *other)
+  {
+    if (!other->is_const ())
+      return false;
+    return m_other_type->is_same_type_as (other->is_const ());
+  }
+
+  virtual type *is_const () { return m_other_type; }
+
   void replay_into (replayer *) FINAL OVERRIDE;
 
 private:
@@ -701,9 +712,18 @@ public:
   memento_of_get_volatile (type *other_type)
   : decorated_type (other_type) {}
 
+  virtual bool is_same_type_as (type *other)
+  {
+    if (!other->is_volatile ())
+      return false;
+    return m_other_type->is_same_type_as (other->is_volatile ());
+  }
+
   /* Strip off the "volatile", giving the underlying type.  */
   type *unqualified () FINAL OVERRIDE { return m_other_type; }
 
+  virtual type *is_volatile () { return m_other_type; }
+
   void replay_into (replayer *) FINAL OVERRIDE;
 
 private:
diff --git a/gcc/testsuite/jit.dg/all-non-failing-tests.h b/gcc/testsuite/jit.dg/all-non-failing-tests.h
index a7fddf96db8..be4a41f8dad 100644
--- a/gcc/testsuite/jit.dg/all-non-failing-tests.h
+++ b/gcc/testsuite/jit.dg/all-non-failing-tests.h
@@ -188,6 +188,13 @@
 #undef create_code
 #undef verify_code
 
+/* test-builtin-types.c */
+#define create_code create_code_builtin_types
+#define verify_code verify_code_builtin_types
+#include "test-builtin-types.c"
+#undef create_code
+#undef verify_code
+
 /* test-hello-world.c */
 #define create_code create_code_hello_world
 #define verify_code verify_code_hello_world
@@ -408,6 +415,9 @@ const struct testcase testcases[] = {
   {"functions",
    create_code_functions,
    verify_code_functions},
+  {"builtin-types",
+   create_code_builtin_types,
+   verify_code_builtin_types},
   {"hello_world",
    create_code_hello_world,
    verify_code_hello_world},
diff --git a/gcc/testsuite/jit.dg/test-builtin-types.c b/gcc/testsuite/jit.dg/test-builtin-types.c
new file mode 100644
index 00000000000..15b026c9593
--- /dev/null
+++ b/gcc/testsuite/jit.dg/test-builtin-types.c
@@ -0,0 +1,43 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <time.h>
+
+#include "libgccjit.h"
+
+#include "harness.h"
+
+void
+create_code (gcc_jit_context *ctxt, void *user_data)
+{
+  CHECK_NON_NULL (gcc_jit_context_get_builtin_function (ctxt, "__atomic_fetch_add_4"));
+
+  gcc_jit_function *atomic_load = gcc_jit_context_get_builtin_function (ctxt, "__atomic_load_8");
+
+  gcc_jit_type *void_type =
+    gcc_jit_context_get_type (ctxt, GCC_JIT_TYPE_VOID);
+  gcc_jit_type *const_void_type =
+    gcc_jit_type_get_const (gcc_jit_context_get_type (ctxt, GCC_JIT_TYPE_VOID));
+  gcc_jit_type *volatile_void_ptr =
+    gcc_jit_type_get_pointer (gcc_jit_type_get_volatile (const_void_type));
+  gcc_jit_type *long_type =
+    gcc_jit_context_get_type (ctxt, GCC_JIT_TYPE_LONG);
+  gcc_jit_type *int_type =
+    gcc_jit_context_get_type (ctxt, GCC_JIT_TYPE_INT);
+  gcc_jit_function *func =
+    gcc_jit_context_new_function (ctxt, NULL, GCC_JIT_FUNCTION_EXPORTED, void_type, "atomics", 0, NULL, 0);
+
+  gcc_jit_lvalue *variable = gcc_jit_function_new_local (func, NULL, long_type, "variable");
+  gcc_jit_rvalue *builtin_args[2];
+  gcc_jit_rvalue *param1 = gcc_jit_lvalue_get_address(variable, NULL);
+  builtin_args[0] = gcc_jit_context_new_cast(ctxt, NULL, param1, volatile_void_ptr);
+  builtin_args[1] = gcc_jit_context_new_rvalue_from_long(ctxt, int_type, 0);
+  gcc_jit_context_new_call (ctxt, NULL, atomic_load, 2, builtin_args);
+}
+
+void
+verify_code (gcc_jit_context *ctxt, gcc_jit_result *result)
+{
+  /* Verify that no errors were emitted.  */
+  CHECK_NON_NULL (result);
+}
diff --git a/gcc/testsuite/jit.dg/test-error-bad-assignment.c b/gcc/testsuite/jit.dg/test-error-bad-assignment.c
new file mode 100644
index 00000000000..fea2b372e1f
--- /dev/null
+++ b/gcc/testsuite/jit.dg/test-error-bad-assignment.c
@@ -0,0 +1,78 @@
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "libgccjit.h"
+
+#include "harness.h"
+
+void
+create_code (gcc_jit_context *ctxt, void *user_data)
+{
+  /* Let's try to inject the equivalent of:
+
+     void
+     test_fn ()
+     {
+        long integer;
+        volatile const void *variable;
+        variable = &integer;
+        long aligned_integer __attribute__((aligned(4)));
+        variable = &aligned_integer;
+     }
+
+     and verify that the API complains about the mismatching types
+     in the assignments.
+  */
+  gcc_jit_type *void_type =
+    gcc_jit_context_get_type (ctxt, GCC_JIT_TYPE_VOID);
+  gcc_jit_type *long_type =
+    gcc_jit_context_get_type (ctxt, GCC_JIT_TYPE_LONG);
+  gcc_jit_type *const_void_type =
+    gcc_jit_type_get_const (void_type);
+  gcc_jit_type *volatile_void_ptr =
+    gcc_jit_type_get_pointer (gcc_jit_type_get_volatile (const_void_type));
+
+  gcc_jit_function *func =
+    gcc_jit_context_new_function (ctxt, NULL,
+                                  GCC_JIT_FUNCTION_EXPORTED,
+                                  void_type,
+                                  "test_fn",
+                                  0, NULL,
+                                  0);
+
+  gcc_jit_lvalue *integer = gcc_jit_function_new_local (func, NULL, long_type, "integer");
+  gcc_jit_rvalue *address = gcc_jit_lvalue_get_address(integer, NULL);
+
+  gcc_jit_lvalue *variable = gcc_jit_function_new_local (func, NULL, volatile_void_ptr, "variable");
+  gcc_jit_block *initial =
+    gcc_jit_function_new_block (func, "initial");
+  gcc_jit_block_add_assignment(initial, NULL, variable, address);
+
+  gcc_jit_type *aligned_long_type = gcc_jit_type_get_aligned (long_type, 4);
+  gcc_jit_lvalue *aligned_integer = gcc_jit_function_new_local (func, NULL, aligned_long_type, "aligned_integer");
+  gcc_jit_rvalue *aligned_address = gcc_jit_lvalue_get_address(aligned_integer, NULL);
+
+  gcc_jit_block_add_assignment(initial, NULL, variable, aligned_address);
+
+  gcc_jit_block_end_with_void_return (initial, NULL);
+}
+
+void
+verify_code (gcc_jit_context *ctxt, gcc_jit_result *result)
+{
+  CHECK_VALUE (result, NULL);
+
+  /* Verify that the correct error messages were emitted.  */
+  CHECK_STRING_VALUE (gcc_jit_context_get_first_error (ctxt),
+		      "gcc_jit_block_add_assignment:"
+		      " mismatching types:"
+		      " assignment to variable (type: volatile const void *)"
+		      " from &integer (type: long *)");
+
+  CHECK_STRING_VALUE (gcc_jit_context_get_last_error (ctxt),
+		      "gcc_jit_block_add_assignment:"
+		      " mismatching types:"
+		      " assignment to variable (type: volatile const void *)"
+		      " from &aligned_integer (type: long  __attribute__((aligned(4))) *)");
+}
+
diff --git a/gcc/testsuite/jit.dg/test-fuzzer.c b/gcc/testsuite/jit.dg/test-fuzzer.c
index 4fd49dacf6d..6fa95d97b32 100644
--- a/gcc/testsuite/jit.dg/test-fuzzer.c
+++ b/gcc/testsuite/jit.dg/test-fuzzer.c
@@ -193,12 +193,18 @@ get_random_type (fuzzer *f)
 static gcc_jit_type *
 make_random_type (fuzzer *f)
 {
-  switch (fuzzer_randrange (f, 0, 5))
+  switch (fuzzer_randrange (f, 0, 8))
     {
     case 0:
       return gcc_jit_type_get_pointer (get_random_type (f));
     case 1:
       return gcc_jit_type_get_const (get_random_type (f));
+    case 2:
+      return gcc_jit_type_get_vector (get_random_type (f), 4);
+    case 3:
+      return gcc_jit_type_get_volatile (get_random_type (f));
+    case 4:
+      return gcc_jit_type_get_aligned (get_random_type (f), 4);
     default:
       {
 	/* Create a struct.  */
-- 
2.26.2.7.g19db9cfb68.dirty