[binutils-gdb] gdb/rust: Handle printing structures containing strings
Andrew Burgess
aburgess@sourceware.org
Thu May 2 21:13:00 GMT 2019
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=80062eb94959467fb0c27b988b87ac08dada4bd8
commit 80062eb94959467fb0c27b988b87ac08dada4bd8
Author: Andrew Burgess <andrew.burgess@embecosm.com>
Date: Thu May 2 00:40:01 2019 +0100
gdb/rust: Handle printing structures containing strings
When printing a rust structure that contains a string GDB can
currently fail to read the fields that define the string. This is
because GDB mistakenly treats a value that is the parent structure as
though it is the structure that defines the string, and then fails to
find the fields needed to extract a string.
The solution is to create a new value to represent the string field of
the parent value.
gdb/ChangeLog:
* rust-lang.c (val_print_struct): Handle printing structures
containing strings.
gdb/testsuite/ChangeLog:
* gdb.rust/simple.exp: Add new test case.
* gdb.rust/simple.rs (struct StringAtOffset): New struct.
(main): Initialise an instance of the new struct.
Diff:
---
gdb/ChangeLog | 5 +++++
gdb/rust-lang.c | 8 ++++++++
gdb/testsuite/ChangeLog | 6 ++++++
gdb/testsuite/gdb.rust/simple.exp | 3 +++
gdb/testsuite/gdb.rust/simple.rs | 8 ++++++++
5 files changed, 30 insertions(+)
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index c36b45c..bef807d 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2019-05-02 Andrew Burgess <andrew.burgess@embecosm.com>
+
+ * rust-lang.c (val_print_struct): Handle printing structures
+ containing strings.
+
2019-05-02 Tom Tromey <tromey@adacore.com>
* valarith.c (_initialize_valarith): Remove.
diff --git a/gdb/rust-lang.c b/gdb/rust-lang.c
index 2fada46..79f1331 100644
--- a/gdb/rust-lang.c
+++ b/gdb/rust-lang.c
@@ -378,6 +378,14 @@ val_print_struct (struct type *type, int embedded_offset,
if (rust_slice_type_p (type) && strcmp (TYPE_NAME (type), "&str") == 0)
{
+ /* If what we are printing here is actually a string within a
+ structure then VAL will be the original parent value, while TYPE
+ will be the type of the structure representing the string we want
+ to print.
+ However, RUST_VAL_PRINT_STR looks up the fields of the string
+ inside VAL, assuming that VAL is the string.
+ So, recreate VAL as a value representing just the string. */
+ val = value_at_lazy (type, value_address (val) + embedded_offset);
rust_val_print_str (stream, val, options);
return;
}
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 0f96ea2..93e2e41 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2019-05-02 Andrew Burgess <andrew.burgess@embecosm.com>
+
+ * gdb.rust/simple.exp: Add new test case.
+ * gdb.rust/simple.rs (struct StringAtOffset): New struct.
+ (main): Initialise an instance of the new struct.
+
2019-05-01 Tom Tromey <tromey@adacore.com>
* gdb.ada/packed_array_assign/aggregates.ads (Nested_Packed): New
diff --git a/gdb/testsuite/gdb.rust/simple.exp b/gdb/testsuite/gdb.rust/simple.exp
index 91afe85..7211bd2 100644
--- a/gdb/testsuite/gdb.rust/simple.exp
+++ b/gdb/testsuite/gdb.rust/simple.exp
@@ -239,6 +239,9 @@ gdb_test "print custom_some" \
" = simple::NonZeroOptimized::Value\\(\[a-z\]+::string::String .*"
gdb_test "print custom_none" " = simple::NonZeroOptimized::Empty"
+gdb_test "print st" \
+ " = simple::StringAtOffset {field1: \"hello\", field2: 1, field3: \"world\"}"
+
proc test_one_slice {svar length base range} {
global hex
diff --git a/gdb/testsuite/gdb.rust/simple.rs b/gdb/testsuite/gdb.rust/simple.rs
index 19f5ef9..e6e0efd 100644
--- a/gdb/testsuite/gdb.rust/simple.rs
+++ b/gdb/testsuite/gdb.rust/simple.rs
@@ -85,6 +85,12 @@ union Union {
f2: u8,
}
+struct StringAtOffset {
+ pub field1: &'static str,
+ pub field2: i32,
+ pub field3: &'static str,
+}
+
// A simple structure whose layout won't be changed by the compiler,
// so that ptype/o testing will work on any platform.
struct SimpleLayout {
@@ -146,6 +152,8 @@ fn main () {
let to1 = &w[..3];
let to2 = &slice[..1];
+ let st = StringAtOffset { field1: "hello", field2: 1, field3: "world" };
+
// tests for enum optimizations
let str_some = Some("hi".to_string());
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