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| author | Luc Van Oostenryck <luc.vanoostenryck@gmail.com> | 2017-04-06 15:50:23 +0200 |
|---|---|---|
| committer | Luc Van Oostenryck <luc.vanoostenryck@gmail.com> | 2017-05-19 05:35:01 +0200 |
| commit | b1672eab399fdce2c050e8aa07767489a2071981 (patch) | |
| tree | 7a7edd535f4747c5e8f84dc6f1ab3181e50746a3 | |
| parent | 816e13f57644116daf20debe548e3e53ec4e5073 (diff) | |
| download | sparse-dev-b1672eab399fdce2c050e8aa07767489a2071981.tar.gz | |
fix implicit zero initializer.
The C standard requires that, when initializing an aggregate, all
fieds not explicitly initialized shall be implicity zero-initialized
(more exactly "the same as objects that have static storage duration"
[6.7.9.21]).
Until now sparse didn't did this.
Fix this (when an initializer is present and the object not a scalar)
by first storing zeroes in the whole object before doing the
initialization of each fields explicitly initialized.
Note 1: this patch initialize the *whole* aggregate while the
standard only requires that existing fields are initialized.
Thanks to Linus to notice this.
Note 2: this implicit initialization is not needed if all fields are
explicitly initialized but is done anyway, for the moment.
Note 3: the code simplify nicely when there is a single field that is
initialized, much less so when there is several ones.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
| -rw-r--r-- | linearize.c | 15 | ||||
| -rw-r--r-- | validation/linear/bitfield-init-zero.c | 102 | ||||
| -rw-r--r-- | validation/linear/struct-init-full.c | 28 | ||||
| -rw-r--r-- | validation/linear/struct-init-partial.c | 41 |
4 files changed, 186 insertions, 0 deletions
diff --git a/linearize.c b/linearize.c index 143f1042..e8a1628b 100644 --- a/linearize.c +++ b/linearize.c @@ -1634,6 +1634,21 @@ static pseudo_t linearize_one_symbol(struct entrypoint *ep, struct symbol *sym) sym->initialized = 1; ad.address = symbol_pseudo(ep, sym); + + if (sym->initializer && !is_scalar_type(sym)) { + // default zero initialization [6.7.9.21] + // FIXME: this init the whole aggregate while + // only the existing fields need to be initialized. + // FIXME: this init the whole aggregate even if + // all fields arelater explicitely initialized. + struct expression *expr = sym->initializer; + ad.pos = expr->pos; + ad.result_type = sym; + ad.source_type = base_type(sym); + ad.address = symbol_pseudo(ep, sym); + linearize_store_gen(ep, value_pseudo(0), &ad); + } + value = linearize_initializer(ep, sym->initializer, &ad); finish_address_gen(ep, &ad); return value; diff --git a/validation/linear/bitfield-init-zero.c b/validation/linear/bitfield-init-zero.c new file mode 100644 index 00000000..39a64345 --- /dev/null +++ b/validation/linear/bitfield-init-zero.c @@ -0,0 +1,102 @@ +struct bfu { + unsigned int a:11; + unsigned int f:9; + unsigned int :2; + unsigned int z:3; +}; + +struct bfu bfuu_init(unsigned int a) +{ + struct bfu bf = { .f = a, }; + return bf; +} + +struct bfu bfus_init(int a) +{ + struct bfu bf = { .f = a, }; + return bf; +} + +unsigned int bfu_get0(void) +{ + struct bfu bf = { }; + return bf.f; +} + + +struct bfs { + signed int a:11; + signed int f:9; + signed int :2; + signed int z:3; +}; + +struct bfs bfsu_init(unsigned int a) +{ + struct bfs bf = { .f = a, }; + return bf; +} + +struct bfs bfss_init(int a) +{ + struct bfs bf = { .f = a, }; + return bf; +} + +int bfs_get0(void) +{ + struct bfs bf = { }; + return bf.f; +} + +/* + * check-name: bitfield implicit init zero + * check-command: test-linearize -Wno-decl $file + * + * check-output-start +bfuu_init: +.L0: + <entry-point> + cast.9 %r2 <- (32) %arg1 + shl.32 %r4 <- %r2, $11 + ret.32 %r4 + + +bfus_init: +.L2: + <entry-point> + scast.9 %r10 <- (32) %arg1 + shl.32 %r12 <- %r10, $11 + ret.32 %r12 + + +bfu_get0: +.L4: + <entry-point> + ret.32 $0 + + +bfsu_init: +.L6: + <entry-point> + cast.9 %r23 <- (32) %arg1 + shl.32 %r25 <- %r23, $11 + ret.32 %r25 + + +bfss_init: +.L8: + <entry-point> + scast.9 %r31 <- (32) %arg1 + shl.32 %r33 <- %r31, $11 + ret.32 %r33 + + +bfs_get0: +.L10: + <entry-point> + ret.32 $0 + + + * check-output-end + */ diff --git a/validation/linear/struct-init-full.c b/validation/linear/struct-init-full.c new file mode 100644 index 00000000..f1b03db7 --- /dev/null +++ b/validation/linear/struct-init-full.c @@ -0,0 +1,28 @@ +struct s { + int a, b, c; +}; + +struct s s_init_all(int a) +{ + struct s s = { .a = a, .b = 42, .c = 123, }; + return s; +} + +/* + * check-name: struct implicit init zero not needed + * check-command: test-linearize -Wno-decl $file + * check-known-to-fail + * + * check-output-start +s_init_all: +.L4: + <entry-point> + store.32 %arg1 -> 0[s] + store.32 $42 -> 4[s] + store.32 $123 -> 8[s] + load.96 %r8 <- 0[s] + ret.96 %r8 + + + * check-output-end + */ diff --git a/validation/linear/struct-init-partial.c b/validation/linear/struct-init-partial.c new file mode 100644 index 00000000..1f5078bf --- /dev/null +++ b/validation/linear/struct-init-partial.c @@ -0,0 +1,41 @@ +struct s { + int a, b, c; +}; + +struct s s_init_first(int a) +{ + struct s s = { .a = a, }; + return s; +} + +struct s s_init_third(int a) +{ + struct s s = { .c = a, }; + return s; +} + +/* + * check-name: struct implicit init zero needed + * check-command: test-linearize -Wno-decl $file + * + * check-output-start +s_init_first: +.L0: + <entry-point> + store.96 $0 -> 0[s] + store.32 %arg1 -> 0[s] + load.96 %r2 <- 0[s] + ret.96 %r2 + + +s_init_third: +.L2: + <entry-point> + store.96 $0 -> 0[s] + store.32 %arg1 -> 8[s] + load.96 %r5 <- 0[s] + ret.96 %r5 + + + * check-output-end + */ |