[PATCH 7/9] Only use stride for final element type

Tom Tromey
2020-09-30T20:07:10Z

A DWARF array type may specify a stride. Currently, the DWARF reader
applies this stride to every dimension of an array. However, this
seems incorrect to me -- only the innermost array ought to use the
stride, while outer arrays should compute a stride based on the size
of the inner arrays. This patch arranges to apply the stride only to
the innermost array type. This fixes a bug noticed when running some
Ada tests with -fgnat-encodings=minimal.

2020-09-30 Tom Tromey <tromey@adacore.com>

* dwarf2/read.c (read_array_type): Only apply stride to innermost
array.

gdb/testsuite/ChangeLog
2020-09-30 Tom Tromey <tromey@adacore.com>

* gdb.ada/enum_idx_packed.exp: Add test.
* gdb.ada/enum_idx_packed/foo.adb (Multi_Access):
New variable.
* gdb.ada/enum_idx_packed/pck.ads (Short)
(Multi_Dimension, Multi_Dimension_Access): New types.
---
gdb/ChangeLog | 5 +++++
gdb/dwarf2/read.c | 16 ++++++++++++----
gdb/testsuite/ChangeLog | 8 ++++++++
gdb/testsuite/gdb.ada/enum_idx_packed.exp | 3 +++
gdb/testsuite/gdb.ada/enum_idx_packed/foo.adb | 5 +++++
gdb/testsuite/gdb.ada/enum_idx_packed/pck.ads | 5 +++++
6 files changed, 38 insertions(+), 4 deletions(-)

diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c
index e3e68fc1f29..9a94c5b349f 100644
--- a/gdb/dwarf2/read.c
+++ b/gdb/dwarf2/read.c
@@ -17089,15 +17089,23 @@ read_array_type (struct die_info *die, struct dwarf2_cu *cu)
int i = 0;

while (i < range_types.size ())
- type = create_array_type_with_stride (NULL, type, range_types[i++],
- byte_stride_prop, bit_stride);
+ {
+ type = create_array_type_with_stride (NULL, type, range_types[i++],
+ byte_stride_prop, bit_stride);
+ bit_stride = 0;
+ byte_stride_prop = nullptr;
+ }
}
else
{
size_t ndim = range_types.size ();
while (ndim-- > 0)
- type = create_array_type_with_stride (NULL, type, range_types[ndim],
- byte_stride_prop, bit_stride);
+ {
+ type = create_array_type_with_stride (NULL, type, range_types[ndim],
+ byte_stride_prop, bit_stride);
+ bit_stride = 0;
+ byte_stride_prop = nullptr;
+ }
}

/* Understand Dwarf2 support for vector types (like they occur on
diff --git a/gdb/testsuite/gdb.ada/enum_idx_packed.exp b/gdb/testsuite/gdb.ada/enum_idx_packed.exp
index 91859689c4a..2e5a85e76b3 100644
--- a/gdb/testsuite/gdb.ada/enum_idx_packed.exp
+++ b/gdb/testsuite/gdb.ada/enum_idx_packed.exp
@@ -118,4 +118,7 @@ foreach_with_prefix scenario {all minimal} {
setup_kfail "minimal encodings" *-*-*
}
gdb_test "print multi_multi(2)" " = $matrix"
+
+ gdb_test "print multi_access.all" \
+ " = \\(\\(8, 13, 21, 34, 55\\), \\(1, 1, 2, 3, 5\\)\\)"
}
diff --git a/gdb/testsuite/gdb.ada/enum_idx_packed/foo.adb b/gdb/testsuite/gdb.ada/enum_idx_packed/foo.adb
index e9f30747167..bc82831bb84 100644
--- a/gdb/testsuite/gdb.ada/enum_idx_packed/foo.adb
+++ b/gdb/testsuite/gdb.ada/enum_idx_packed/foo.adb
@@ -22,6 +22,10 @@ procedure Foo is
Small : Small_Table := New_Small_Table (Low => Red, High => Green);
Multi : Multi_Table := New_Multi_Table (Red, Green, Low, Medium);
Multi_Multi : Multi_Multi_Table := New_Multi_Multi_Table (1, 2, 1, 7, 1, 10);
+ Multi_Access : Multi_Dimension_Access
+ := new Multi_Dimension'(True => (1, 1, 2, 3, 5),
+ False => (8, 13, 21, 34, 55));
+
begin
Do_Nothing (Full'Address); -- STOP
Do_Nothing (Primary'Address);
@@ -29,4 +33,5 @@ begin
Do_Nothing (Small'Address);
Do_Nothing (Multi'Address);
Do_Nothing (Multi_Multi'Address);
+ Do_Nothing (Multi_Access'Address);
end Foo;
diff --git a/gdb/testsuite/gdb.ada/enum_idx_packed/pck.ads b/gdb/testsuite/gdb.ada/enum_idx_packed/pck.ads
index fdfd8bbc4c6..7fe5a9e01d4 100644
--- a/gdb/testsuite/gdb.ada/enum_idx_packed/pck.ads
+++ b/gdb/testsuite/gdb.ada/enum_idx_packed/pck.ads
@@ -17,6 +17,7 @@ with System;
package Pck is
type Color is (Black, Red, Green, Blue, White);
type Strength is (None, Low, Medium, High);
+ type Short is new Natural range 0 .. 2 ** 8 - 1;

type Full_Table is array (Color) of Boolean;
pragma Pack (Full_Table);
@@ -43,5 +44,9 @@ package Pck is
function New_Multi_Multi_Table (L1, H1, L2, H2, L3, H3: Positive)
return Multi_Multi_Table;

+ type Multi_Dimension is array (Boolean, Color) of Short;
+ pragma Pack (Multi_Dimension);
+ type Multi_Dimension_Access is access all Multi_Dimension;
+
procedure Do_Nothing (A : System.Address);
end Pck;
--
2.26.2