Currently, Sparse treats 'plain' bitfields as unsigned.
However, this is this is inconsistent with how non-bitfield integers
are handled and with how GCC & clang handle bitfields.
So, teach sparse about '-funsigned-bitfields' and by default treat
these bitfields are signed, like done by GCC & clang and like done
for non-bitfield integers.
Also, avoid plain bitfields in IR related testcases.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx>
---
options.c | 3 +++
options.h | 1 +
sparse.1 | 6 ++++++
symbol.c | 4 ++--
validation/linear/bitfield-sign-default.c | 13 +++++++++++++
validation/linear/bitfield-sign-signed.c | 13 +++++++++++++
validation/linear/bitfield-sign-unsigned.c | 13 +++++++++++++
validation/linear/bitfield-size.c | 10 +++++-----
validation/optim/bitfield-size.c | 15 ++-------------
validation/optim/bitfield-store-loads.c | 4 ++--
10 files changed, 60 insertions(+), 22 deletions(-)
create mode 100644 validation/linear/bitfield-sign-default.c
create mode 100644 validation/linear/bitfield-sign-signed.c
create mode 100644 validation/linear/bitfield-sign-unsigned.c
diff --git a/options.c b/options.c
index 294dfd3be77a..a12d28669e05 100644
--- a/options.c
+++ b/options.c
@@ -81,6 +81,7 @@ unsigned long fpasses = ~0UL;
int fpic = 0;
int fpie = 0;
int fshort_wchar = 0;
+int funsigned_bitfields = 0;
int funsigned_char = 0;
int Waddress = 0;
@@ -524,6 +525,8 @@ static struct flag fflags[] = {
{ "PIC", &fpic, handle_switch_setval, 2 },
{ "pie", &fpie, handle_switch_setval, 1 },
{ "PIE", &fpie, handle_switch_setval, 2 },
+ { "signed-bitfields", &funsigned_bitfields, NULL, OPT_INVERSE },
+ { "unsigned-bitfields", &funsigned_bitfields, NULL, },
{ "signed-char", &funsigned_char, NULL, OPT_INVERSE },
{ "short-wchar", &fshort_wchar },
{ "unsigned-char", &funsigned_char, NULL, },
diff --git a/options.h b/options.h
index abdf08645ad2..8e3071a755be 100644
--- a/options.h
+++ b/options.h
@@ -80,6 +80,7 @@ extern unsigned long fpasses;
extern int fpic;
extern int fpie;
extern int fshort_wchar;
+extern int funsigned_bitfields;
extern int funsigned_char;
extern int Waddress;
diff --git a/sparse.1 b/sparse.1
index 48dab7a9a5c1..2a8eb1249da1 100644
--- a/sparse.1
+++ b/sparse.1
@@ -518,6 +518,12 @@ column numbers in warnings or errors. If the value is less than 1 or
greater than 100, the option is ignored. The default is 8.
.
.TP
+.B \-f[no-]unsigned-bitfields, \-f[no-]signed-bitfields
+Determine the signedness of bitfields declared without an
+explicit sign ('signed' or 'unsigned').
+By default such bitfields are signed, like others plain integers.
+.
+.TP
.B \-f[no-]unsigned-char, \-f[no-]signed-char
Let plain 'char' be unsigned or signed.
By default chars are signed.
diff --git a/symbol.c b/symbol.c
index 7f0c85580f06..aaeb8c100436 100644
--- a/symbol.c
+++ b/symbol.c
@@ -286,8 +286,8 @@ static struct symbol *examine_bitfield_type(struct symbol *sym)
sym->ctype.alignment = alignment;
modifiers = base_type->ctype.modifiers;
- /* Bitfields are unsigned, unless the base type was explicitly signed */
- if (!(modifiers & MOD_EXPLICITLY_SIGNED))
+ /* use -funsigned-bitfields to determine the sign if not explicit */
+ if (!(modifiers & MOD_EXPLICITLY_SIGNED) && funsigned_bitfields)
modifiers = (modifiers & ~MOD_SIGNED) | MOD_UNSIGNED;
sym->ctype.modifiers |= modifiers & MOD_SIGNEDNESS;
return sym;
diff --git a/validation/linear/bitfield-sign-default.c b/validation/linear/bitfield-sign-default.c
new file mode 100644
index 000000000000..9a2854e63c47
--- /dev/null
+++ b/validation/linear/bitfield-sign-default.c
@@ -0,0 +1,13 @@
+struct s {
+ int f:2;
+};
+
+static int getf(struct s s) { return s.f; }
+
+/*
+ * check-name: bitfield-sign-default
+ * check-command: test-linearize -fdump-ir=linearize $file
+ *
+ * check-output-ignore
+ * check-output-contains: sext\\.
+ */
diff --git a/validation/linear/bitfield-sign-signed.c b/validation/linear/bitfield-sign-signed.c
new file mode 100644
index 000000000000..59a07cebebc7
--- /dev/null
+++ b/validation/linear/bitfield-sign-signed.c
@@ -0,0 +1,13 @@
+struct s {
+ int f:2;
+};
+
+static int getf(struct s s) { return s.f; }
+
+/*
+ * check-name: bitfield-sign-signed
+ * check-command: test-linearize -fdump-ir=linearize -fsigned-bitfields $file
+ *
+ * check-output-ignore
+ * check-output-contains: sext\\.
+ */
diff --git a/validation/linear/bitfield-sign-unsigned.c b/validation/linear/bitfield-sign-unsigned.c
new file mode 100644
index 000000000000..099edaad979a
--- /dev/null
+++ b/validation/linear/bitfield-sign-unsigned.c
@@ -0,0 +1,13 @@
+struct s {
+ int f:2;
+};
+
+static int getf(struct s s) { return s.f; }
+
+/*
+ * check-name: bitfield-sign-unsigned
+ * check-command: test-linearize -fdump-ir=linearize -funsigned-bitfields $file
+ *
+ * check-output-ignore
+ * check-output-contains: zext\\.
+ */
diff --git a/validation/linear/bitfield-size.c b/validation/linear/bitfield-size.c
index dcda930dc510..719b0ab85fcc 100644
--- a/validation/linear/bitfield-size.c
+++ b/validation/linear/bitfield-size.c
@@ -19,7 +19,7 @@ void ucpy(struct u *d, const struct u *s)
struct s {
- int f:3;
+ signed int f:3;
};
int spostinc(struct s *x)
@@ -118,7 +118,7 @@ spostinc:
load.64 %r33 <- 0[x]
load.32 %r34 <- 0[%r33]
trunc.3 %r35 <- (32) %r34
- zext.32 %r36 <- (3) %r35
+ sext.32 %r36 <- (3) %r35
add.32 %r37 <- %r36, $1
trunc.3 %r38 <- (32) %r37
load.32 %r39 <- 0[%r33]
@@ -126,7 +126,7 @@ spostinc:
and.32 %r41 <- %r39, $0xfffffff8
or.32 %r42 <- %r41, %r40
store.32 %r42 -> 0[%r33]
- zext.32 %r43 <- (3) %r36
+ sext.32 %r43 <- (3) %r36
phisrc.32 %phi3(return) <- %r43
br .L7
@@ -142,7 +142,7 @@ spreinc:
load.64 %r45 <- 0[x]
load.32 %r46 <- 0[%r45]
trunc.3 %r47 <- (32) %r46
- zext.32 %r48 <- (3) %r47
+ sext.32 %r48 <- (3) %r47
add.32 %r49 <- %r48, $1
trunc.3 %r50 <- (32) %r49
load.32 %r51 <- 0[%r45]
@@ -150,7 +150,7 @@ spreinc:
and.32 %r53 <- %r51, $0xfffffff8
or.32 %r54 <- %r53, %r52
store.32 %r54 -> 0[%r45]
- zext.32 %r55 <- (3) %r50
+ sext.32 %r55 <- (3) %r50
phisrc.32 %phi4(return) <- %r55
br .L9
diff --git a/validation/optim/bitfield-size.c b/validation/optim/bitfield-size.c
index 0d2deeeac2dd..ea1ed57fb8fe 100644
--- a/validation/optim/bitfield-size.c
+++ b/validation/optim/bitfield-size.c
@@ -19,17 +19,6 @@ signed int get__bfs_b(struct bfs bf) { return bf.b; }
signed int get_pbfs_a(struct bfs *bf) { return bf->a; }
signed int get_pbfs_b(struct bfs *bf) { return bf->b; }
-
-struct bfi {
- int a:4;
- int :2;
- int b:4;
-};
-unsigned int get__bfi_a(struct bfi bf) { return bf.a; }
-unsigned int get__bfi_b(struct bfi bf) { return bf.b; }
-unsigned int get_pbfi_a(struct bfi *bf) { return bf->a; }
-unsigned int get_pbfi_b(struct bfi *bf) { return bf->b; }
-
/*
* check-name: bitfield size
* check-command: test-linearize -Wno-decl $file
@@ -37,8 +26,8 @@ unsigned int get_pbfi_b(struct bfi *bf) { return bf->b; }
*
* check-output-excludes: and\\..*\\$960
* check-output-excludes: zext\\.
- * check-output-pattern(8): and\\..*\\$15
+ * check-output-pattern(4): and\\..*\\$15
* check-output-pattern(4): sext\\.
* check-output-pattern(4): trunc\\.4
- * check-output-pattern(6): lsr\\..*\\$6
+ * check-output-pattern(4): lsr\\..*\\$6
*/
diff --git a/validation/optim/bitfield-store-loads.c b/validation/optim/bitfield-store-loads.c
index dc625131e188..f946715bffa3 100644
--- a/validation/optim/bitfield-store-loads.c
+++ b/validation/optim/bitfield-store-loads.c
@@ -1,6 +1,6 @@
struct s {
- char :2;
- char f:3;
+ unsigned char :2;
+ unsigned char f:3;
};
int foo(struct s s, int a)
--
2.28.0
