[PATCH 2/4] gdb/types: Resolve pointer types dynamically

[Nils-Christian Kempke <nils-christian.kempke@intel.com>]

From: Bernhard Heckel <bernhard.heckel@intel.com>

This commit allows pointers to be dynamic types (on the outmost
level).  Similar to references, a pointer is considered a dynamic type
if its target type is a dynamic type and it is on the outmost level.

When resolving a dynamic pointer in resolve_dynamic_pointer
we a) try and resolve its target type (in a similar fashion as it is
done for references) and b) resolve the dynamic DW_AT_associated
property, which is emitted by ifx and ifort for pointers.

This generally makes the GDB output more verbose.  We are able to print
more details about a pointer's target like the dimension of an array.

In Fortran, if we have a pointer to a dynamic type

  type buffer
    real, dimension(:), pointer :: ptr
  end type buffer
  type(buffer), pointer :: buffer_ptr
  allocate (buffer_ptr)
  allocate (buffer_ptr%ptr (5))

which then gets allocated, we now resolve the dynamic type before
printing the pointer's type:

Before:

  (gdb) ptype buffer_ptr
  type = PTR TO -> ( Type buffer
    real(kind=4) :: alpha(:)
  End Type buffer )

After:

  (gdb) ptype buffer_ptr
  type = PTR TO -> ( Type buffer
    real(kind=4) :: alpha(5)
  End Type buffer )

Similarly in C++ we can dynamically resolve e.g. pointers to arrays:

  int len = 3;
  int arr[len];
  int (*ptr)[len];
  int ptr = &arr;

Once the pointer is assigned one gets:

Before:

  (gdb) p ptr
  $1 = (int (*)[variable length]) 0x123456
  (gdb) ptype ptr
  type = int (*)[variable length]

After:

  (gdb) p ptr
  $1 = (int (*)[3]) 0x123456
  (gdb) ptype ptr
  type = int (*)[3]

For more examples see the modified/added test cases.
---
 gdb/gdbtypes.c                                |  53 +++++-
 gdb/testsuite/gdb.cp/vla-cxx.cc               |   4 +
 gdb/testsuite/gdb.cp/vla-cxx.exp              |  33 ++++
 gdb/testsuite/gdb.dwarf2/dynarr-ptr.exp       |  16 +-
 .../gdb.fortran/pointer-to-pointer.exp        |   2 +-
 gdb/testsuite/gdb.fortran/pointers.exp        | 178 ++++++++++++++++++
 gdb/testsuite/gdb.fortran/pointers.f90        |  29 +++
 gdb/valprint.c                                |   6 -
 8 files changed, 303 insertions(+), 18 deletions(-)
 create mode 100644 gdb/testsuite/gdb.fortran/pointers.exp

diff --git a/gdb/gdbtypes.c b/gdb/gdbtypes.c
index c458b204157..a4d79a64e95 100644
--- a/gdb/gdbtypes.c
+++ b/gdb/gdbtypes.c
@@ -2083,9 +2083,15 @@ is_dynamic_type_internal (struct type *type, int top_level)
 {
   type = check_typedef (type);
 
-  /* We only want to recognize references at the outermost level.  */
-  if (top_level && type->code () == TYPE_CODE_REF)
-    type = check_typedef (TYPE_TARGET_TYPE (type));
+  /* We only want to recognize references and pointers at the outermost
+     level.  */
+  if (type->code () == TYPE_CODE_REF || type->code () == TYPE_CODE_PTR)
+  {
+    if (top_level != 0)
+      type = check_typedef (TYPE_TARGET_TYPE (type));
+    else
+      return 0;
+  }
 
   /* Types that have a dynamic TYPE_DATA_LOCATION are considered
      dynamic, even if the type itself is statically defined.
@@ -2787,6 +2793,43 @@ resolve_dynamic_struct (struct type *type,
   return resolved_type;
 }
 
+/* Worker for pointer types.  */
+
+static struct type *
+resolve_dynamic_pointer (struct type *type,
+			 struct property_addr_info *addr_stack)
+{
+  struct dynamic_prop *prop;
+  CORE_ADDR value;
+
+  /* Resolve the target type of this type.  */
+  struct property_addr_info pinfo;
+  pinfo.type = check_typedef (TYPE_TARGET_TYPE (type));
+  pinfo.valaddr = {};
+  if (addr_stack->valaddr.data () != NULL)
+    pinfo.addr = extract_typed_address (addr_stack->valaddr.data (),
+					type);
+  else
+    pinfo.addr = read_memory_typed_address (addr_stack->addr, type);
+  pinfo.next = addr_stack;
+
+  struct type* resolved_type = copy_type (type);
+
+  /* Resolve associated property.  */
+  prop = TYPE_ASSOCIATED_PROP (resolved_type);
+  if (prop != nullptr
+      && dwarf2_evaluate_property (prop, nullptr, addr_stack, &value))
+    prop->set_const_val (value);
+
+  if (pinfo.addr != 0x0 && !type_not_associated (resolved_type))
+    TYPE_TARGET_TYPE (resolved_type)
+      = resolve_dynamic_type_internal (TYPE_TARGET_TYPE (type),
+				       &pinfo, 0);
+
+
+  return resolved_type;
+}
+
 /* Worker for resolved_dynamic_type.  */
 
 static struct type *
@@ -2842,6 +2885,10 @@ resolve_dynamic_type_internal (struct type *type,
 	    break;
 	  }
 
+	case TYPE_CODE_PTR:
+	  resolved_type = resolve_dynamic_pointer (type, addr_stack);
+	  break;
+
 	case TYPE_CODE_STRING:
 	  /* Strings are very much like an array of characters, and can be
 	     treated as one here.  */
diff --git a/gdb/testsuite/gdb.cp/vla-cxx.cc b/gdb/testsuite/gdb.cp/vla-cxx.cc
index 9795f8cc39b..c03d1a80ac8 100644
--- a/gdb/testsuite/gdb.cp/vla-cxx.cc
+++ b/gdb/testsuite/gdb.cp/vla-cxx.cc
@@ -40,6 +40,10 @@ int main(int argc, char **argv)
   typedef typeof (vla) &vlareftypedef;
   vlareftypedef vlaref2 (vla);
   container c;
+  typeof (vla) *ptr = nullptr;
+
+  // Before pointer assignment
+  ptr = &vla;
 
   for (int i = 0; i < z; ++i)
     vla[i] = 5 + 2 * i;
diff --git a/gdb/testsuite/gdb.cp/vla-cxx.exp b/gdb/testsuite/gdb.cp/vla-cxx.exp
index 3494b5e8b77..e2bb8989212 100644
--- a/gdb/testsuite/gdb.cp/vla-cxx.exp
+++ b/gdb/testsuite/gdb.cp/vla-cxx.exp
@@ -23,6 +23,36 @@ if ![runto_main] {
     return -1
 }
 
+gdb_breakpoint [gdb_get_line_number "Before pointer assignment"]
+gdb_continue_to_breakpoint "Before pointer assignment"
+
+set test_name "ptype ptr, Before pointer assignment"
+gdb_test_multiple "ptype ptr" $test_name {
+  # gcc/icx
+  -re -wrap "= int \\(\\*\\)\\\[variable length\\\]" {
+    pass $test_name
+  }
+  # icc
+  -re -wrap "= int \\(\\*\\)\\\[3\\\]" {
+    pass $test_name
+  }
+}
+
+set test_name "print ptr, Before pointer assignment"
+gdb_test_multiple "print ptr" $test_name {
+  # gcc/icx
+  -re -wrap "= \\(int \\(\\*\\)\\\[variable length\\\]\\) 0x0" {
+    pass $test_name
+  }
+  # icc
+  -re -wrap "= \\(int \\(\\*\\)\\\[3\\\]\\) 0x0" {
+    pass $test_name
+  }
+}
+
+gdb_test "print *ptr" "Cannot access memory at address 0x0" \
+    "print *ptr, Before pointer assignment"
+
 gdb_breakpoint [gdb_get_line_number "vlas_filled"]
 gdb_continue_to_breakpoint "vlas_filled"
 
@@ -33,3 +63,6 @@ gdb_test "print vlaref" " = \\(int \\(&\\)\\\[3\\\]\\) @$hex: \\{5, 7, 9\\}"
 # bug being tested, it's better not to depend on the exact spelling.
 gdb_test "print vlaref2" " = \\(.*\\) @$hex: \\{5, 7, 9\\}"
 gdb_test "print c" " = \\{e = \\{c = @$hex\\}\\}"
+gdb_test "ptype ptr" "int \\(\\*\\)\\\[3\\\]"
+gdb_test "print ptr" "\\(int \\(\\*\\)\\\[3\\\]\\) $hex"
+gdb_test "print *ptr" " = \\{5, 7, 9\\}"
diff --git a/gdb/testsuite/gdb.dwarf2/dynarr-ptr.exp b/gdb/testsuite/gdb.dwarf2/dynarr-ptr.exp
index 83a5fccd831..7c7cf12c4eb 100644
--- a/gdb/testsuite/gdb.dwarf2/dynarr-ptr.exp
+++ b/gdb/testsuite/gdb.dwarf2/dynarr-ptr.exp
@@ -156,7 +156,7 @@ gdb_test "print foo.three_ptr.all'length" \
          " = 3"
 
 gdb_test "ptype foo.three_ptr.all" \
-         " = array \\(<>\\) of integer"
+         " = array \\(1 \\.\\. 3\\) of integer"
 
 # foo.three_ptr
 
@@ -179,7 +179,7 @@ gdb_test "print foo.three_ptr'length" \
          " = 3"
 
 gdb_test "ptype foo.three_ptr" \
-         " = access array \\(<>\\) of integer"
+         " = access array \\(1 \\.\\. 3\\) of integer"
 
 # foo.three_ptr_tdef.all
 
@@ -205,7 +205,7 @@ gdb_test "print foo.three_ptr_tdef.all'length" \
          " = 3"
 
 gdb_test "ptype foo.three_ptr_tdef.all" \
-         " = array \\(<>\\) of integer"
+         " = array \\(1 \\.\\. 3\\) of integer"
 
 # foo.three_ptr_tdef
 
@@ -228,7 +228,7 @@ gdb_test "print foo.three_ptr_tdef'length" \
          " = 3"
 
 gdb_test "ptype foo.three_ptr_tdef" \
-         " = access array \\(<>\\) of integer"
+         " = access array \\(1 \\.\\. 3\\) of integer"
 
 # foo.five_ptr.all
 
@@ -260,7 +260,7 @@ gdb_test "print foo.five_ptr.all'length" \
          " = 5"
 
 gdb_test "ptype foo.five_ptr.all" \
-         " = array \\(<>\\) of integer"
+         " = array \\(2 \\.\\. 6\\) of integer"
 
 # foo.five_ptr
 
@@ -289,7 +289,7 @@ gdb_test "print foo.five_ptr'length" \
          " = 5"
 
 gdb_test "ptype foo.five_ptr" \
-         " = access array \\(<>\\) of integer"
+         " = access array \\(2 \\.\\. 6\\) of integer"
 
 # foo.five_ptr_tdef.all
 
@@ -321,7 +321,7 @@ gdb_test "print foo.five_ptr_tdef.all'length" \
          " = 5"
 
 gdb_test "ptype foo.five_ptr_tdef.all" \
-         " = array \\(<>\\) of integer"
+         " = array \\(2 \\.\\. 6\\) of integer"
 
 # foo.five_ptr_tdef
 
@@ -350,4 +350,4 @@ gdb_test "print foo.five_ptr_tdef'length" \
          " = 5"
 
 gdb_test "ptype foo.five_ptr_tdef" \
-         " = access array \\(<>\\) of integer"
+         " = access array \\(2 \\.\\. 6\\) of integer"
diff --git a/gdb/testsuite/gdb.fortran/pointer-to-pointer.exp b/gdb/testsuite/gdb.fortran/pointer-to-pointer.exp
index 8c43d177295..fcaa4bc9708 100644
--- a/gdb/testsuite/gdb.fortran/pointer-to-pointer.exp
+++ b/gdb/testsuite/gdb.fortran/pointer-to-pointer.exp
@@ -41,7 +41,7 @@ gdb_test "print buffer" \
 gdb_test "ptype buffer" \
     [multi_line \
 	 "type = PTR TO -> \\( Type l_buffer" \
-	 "    $real4 :: alpha\\(:\\)" \
+	 "    $real4 :: alpha\\(5\\)" \
 	 "End Type l_buffer \\)" ]
 gdb_test "ptype buffer%alpha" "type = $real4 \\(5\\)"
 
diff --git a/gdb/testsuite/gdb.fortran/pointers.exp b/gdb/testsuite/gdb.fortran/pointers.exp
new file mode 100644
index 00000000000..3e9e6d26f3b
--- /dev/null
+++ b/gdb/testsuite/gdb.fortran/pointers.exp
@@ -0,0 +1,178 @@
+# Copyright 2022 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+standard_testfile "pointers.f90"
+load_lib fortran.exp
+
+if {[prepare_for_testing ${testfile}.exp ${testfile} ${srcfile} \
+    {debug f90 quiet}]} {
+    return -1
+}
+
+if {![fortran_runto_main]} {
+    untested "could not run to main"
+    return -1
+}
+
+# Depending on the compiler being used, the type names can be printed differently.
+set logical [fortran_logical4]
+set real [fortran_real4]
+set int [fortran_int4]
+set complex [fortran_complex4]
+
+gdb_breakpoint [gdb_get_line_number "Before pointer assignment"]
+gdb_continue_to_breakpoint "Before pointer assignment"
+gdb_test "print logp" "= \\(PTR TO -> \\( $logical \\)\\) 0x0" \
+    "print logp, not associated"
+gdb_test "print *logp" "Cannot access memory at address 0x0" \
+    "print *logp, not associated"
+gdb_test "print comp" "= \\(PTR TO -> \\( $complex \\)\\) 0x0" \
+    "print comp, not associated"
+gdb_test "print *comp" "Cannot access memory at address 0x0" \
+    "print *comp, not associated"
+gdb_test "print charp" "= \\(PTR TO -> \\( character\\*1 \\)\\) 0x0" \
+    "print charp, not associated"
+gdb_test "print *charp" "Cannot access memory at address 0x0" \
+    "print *charp, not associated"
+gdb_test "print charap" "= \\(PTR TO -> \\( character\\*3 \\)\\) 0x0" \
+    "print charap, not associated"
+gdb_test "print *charap" "Cannot access memory at address 0x0" \
+    "print *charap, not associated"
+gdb_test "print intp" "= \\(PTR TO -> \\( $int \\)\\) 0x0" \
+    "print intp, not associated"
+gdb_test "print *intp" "Cannot access memory at address 0x0" \
+    "print *intp, not associated"
+
+set test "print intap, not associated"
+gdb_test_multiple "print intap" $test {
+    # gfortran/ifx
+    -re -wrap " = <not associated>" {
+	pass $test
+    }
+    # ifort
+    -re -wrap " = \\(PTR TO -> \\( $int \\(:,:\\) \\)\\) <not associated>" {
+	pass $test
+    }
+}
+
+gdb_test "print realp" "= \\(PTR TO -> \\( $real \\)\\) 0x0" \
+    "print realp, not associated"
+gdb_test "print *realp" "Cannot access memory at address 0x0" \
+    "print *realp, not associated"
+gdb_test "print \$my_var = intp" "= \\(PTR TO -> \\( $int \\)\\) 0x0"
+set test "print cyclicp1, not associated"
+gdb_test_multiple "print cyclicp1" $test {
+    # gfortran/ifx
+    -re -wrap "= \\( i = -?\\d+, p = 0x0 \\)" {
+	pass $test
+    }
+    # ifort
+    -re -wrap "= \\( i = -?\\d+, p = <not associated> \\)" {
+	pass $test
+    }
+}
+
+set test "print cyclicp1%p, not associated"
+gdb_test_multiple "print cyclicp1%p" $test {
+    # gfortran/ifx
+    -re -wrap "= \\(PTR TO -> \\( Type typewithpointer \\)\\) 0x0" {
+	pass $test
+    }
+    # ifort
+    -re -wrap "= \\(PTR TO -> \\( Type typewithpointer \\)\\) <not associated>" {
+	pass $test
+    }
+}
+
+gdb_breakpoint [gdb_get_line_number "Before value assignment"]
+gdb_continue_to_breakpoint "Before value assignment"
+gdb_test "print *(twop)%ivla2" "= <not allocated>"
+
+gdb_breakpoint [gdb_get_line_number "After value assignment"]
+gdb_continue_to_breakpoint "After value assignment"
+gdb_test "print logp" "= \\(PTR TO -> \\( $logical \\)\\) $hex\( <.*>\)?"
+gdb_test "print *logp" "= \\.TRUE\\."
+gdb_test "print comp" "= \\(PTR TO -> \\( $complex \\)\\) $hex\( <.*>\)?"
+gdb_test "print *comp" "= \\(1,2\\)"
+gdb_test "print charp" "= \\(PTR TO -> \\( character\\*1 \\)\\) $hex\( <.*>\)?"
+gdb_test "print *charp" "= 'a'"
+gdb_test "print charap" "= \\(PTR TO -> \\( character\\*3 \\)\\) $hex\( <.*>\)?"
+gdb_test "print *charap" "= 'abc'"
+gdb_test "print intp" "= \\(PTR TO -> \\( $int \\)\\) $hex\( <.*>\)?"
+gdb_test "print *intp" "= 10"
+
+set test_name "print intap, associated"
+gdb_test_multiple "print intap" $test_name {
+    # gfortran/ifx
+    -re -wrap "= \\(\\(1, 1, 3(, 1){7}\\) \\(1(, 1){9}\\)\\)" {
+	pass $test_name
+    }
+    # ifort
+    -re -wrap "= \\(PTR TO -> \\( $int \\(10,2\\) \\)\\) $hex\( <.*>\)?" {
+	gdb_test "print *intap" "= \\(\\(1, 1, 3(, 1){7}\\) \\(1(, 1){9}\\)\\)"
+	pass $test_name
+    }
+}
+
+set test_name "print intvlap, associated"
+gdb_test_multiple "print intvlap" $test_name {
+    # gfortran/ifx
+    -re -wrap "= \\(2, 2, 2, 4(, 2){6}\\)" {
+	pass $test_name
+    }
+    # ifort
+    -re -wrap "= \\(PTR TO -> \\( $int \\(10\\) \\)\\) $hex\( <.*>\)?" {
+	gdb_test "print *intvlap" "= \\(2, 2, 2, 4(, 2){6}\\)"
+	pass $test_name
+    }
+}
+
+gdb_test "print realp" "= \\(PTR TO -> \\( $real \\)\\) $hex\( <.*>\)?"
+gdb_test "print *realp" "= 3\\.14000\\d+"
+gdb_test "print arrayOfPtr(2)%p" "= \\(PTR TO -> \\( Type two \\)\\) $hex\( <.*>\)?"
+gdb_test "print *(arrayOfPtr(2)%p)" \
+    "= \\( ivla1 = \\(11, 12, 13\\), ivla2 = \\(\\(211, 221\\) \\(212, 222\\)\\) \\)"
+
+set test_name "print arrayOfPtr(3)%p"
+gdb_test_multiple $test_name $test_name {
+    # gfortran/ifx
+    -re -wrap "= \\(PTR TO -> \\( Type two \\)\\) 0x0" {
+	pass $test_name
+    }
+    # ifort
+     -re -wrap "= \\(PTR TO -> \\( Type two \\)\\) <not associated>" {
+	pass $test_name
+    }
+}
+
+set test "print *(arrayOfPtr(3)%p)"
+set test_name "print *(arrayOfPtr(3)%p), associated"
+gdb_test_multiple $test $test_name {
+    # gfortran/ifx
+    -re -wrap "Cannot access memory at address 0x0" {
+	pass $test_name
+    }
+    # ifort
+    -re -wrap "Location address is not set." {
+	pass $test_name
+    }
+}
+
+gdb_test "print cyclicp1" "= \\( i = 1, p = $hex\( <.*>\)? \\)"
+gdb_test "print cyclicp1%p" "= \\(PTR TO -> \\( Type typewithpointer \\)\\) $hex\( <.*>\)?"
+gdb_test "print *((integer*) &inta + 2)" "= 3" "print temporary pointer, array"
+gdb_test "print *((integer*) &intvla + 3)" "= 4" "print temporary pointer, allocated vla"
+gdb_test "print \$pc" "\\(PTR TO -> \\( void \\(\\) \\(\\) \\)\\) $hex <pointers\\+\\d+>" \
+    "Print program counter"
diff --git a/gdb/testsuite/gdb.fortran/pointers.f90 b/gdb/testsuite/gdb.fortran/pointers.f90
index 7f628662546..e480bdc7fbb 100644
--- a/gdb/testsuite/gdb.fortran/pointers.f90
+++ b/gdb/testsuite/gdb.fortran/pointers.f90
@@ -20,14 +20,26 @@ program pointers
     integer, allocatable :: ivla2 (:, :)
   end type two
 
+  type :: typeWithPointer
+    integer i
+    type(typeWithPointer), pointer:: p
+  end type typeWithPointer
+
+  type :: twoPtr
+    type (two), pointer :: p
+  end type twoPtr
+
   logical, target :: logv
   complex, target :: comv
   character, target :: charv
   character (len=3), target :: chara
   integer, target :: intv
   integer, target, dimension (10,2) :: inta
+  integer, target, allocatable, dimension (:) :: intvla
   real, target :: realv
   type(two), target :: twov
+  type(twoPtr) :: arrayOfPtr (3)
+  type(typeWithPointer), target:: cyclicp1,cyclicp2
 
   logical, pointer :: logp
   complex, pointer :: comp
@@ -35,6 +47,7 @@ program pointers
   character (len=3), pointer :: charap
   integer, pointer :: intp
   integer, pointer, dimension (:,:) :: intap
+  integer, pointer, dimension (:) :: intvlap
   real, pointer :: realp
   type(two), pointer :: twop
 
@@ -44,8 +57,14 @@ program pointers
   nullify (charap)
   nullify (intp)
   nullify (intap)
+  nullify (intvlap)
   nullify (realp)
   nullify (twop)
+  nullify (arrayOfPtr(1)%p)
+  nullify (arrayOfPtr(2)%p)
+  nullify (arrayOfPtr(3)%p)
+  nullify (cyclicp1%p)
+  nullify (cyclicp2%p)
 
   logp => logv    ! Before pointer assignment
   comp => comv
@@ -53,8 +72,14 @@ program pointers
   charap => chara
   intp => intv
   intap => inta
+  intvlap => intvla
   realp => realv
   twop => twov
+  arrayOfPtr(2)%p => twov
+  cyclicp1%i = 1
+  cyclicp1%p => cyclicp2
+  cyclicp2%i = 2
+  cyclicp2%p => cyclicp1
 
   logv = associated(logp)     ! Before value assignment
   comv = cmplx(1,2)
@@ -63,6 +88,10 @@ program pointers
   intv = 10
   inta(:,:) = 1
   inta(3,1) = 3
+  allocate (intvla(10))
+  intvla(:) = 2
+  intvla(4) = 4
+  intvlap => intvla
   realv = 3.14
 
   allocate (twov%ivla1(3))
diff --git a/gdb/valprint.c b/gdb/valprint.c
index 3ad4c0cd357..0c3066602fe 100644
--- a/gdb/valprint.c
+++ b/gdb/valprint.c
@@ -1137,12 +1137,6 @@ value_check_printable (struct value *val, struct ui_file *stream,
       return 0;
     }
 
-  if (type_not_associated (value_type (val)))
-    {
-      val_print_not_associated (stream);
-      return 0;
-    }
-
   if (type_not_allocated (value_type (val)))
     {
       val_print_not_allocated (stream);
-- 
2.25.1

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