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Merged
merged 11 commits into from
Sep 26, 2023
Merged

Implement const generics and allow .llvm.<hash> suffixes #2

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c3d070e
Fix a couple of compiler warnings
bjorn3 Aug 31, 2023
77260ed
FIx demangle_extra_suffix and demangle_thinlto tests
bjorn3 Aug 31, 2023
be20a56
Support signed integers and strings in const generics
bjorn3 Aug 31, 2023
2e432c1
Finish const generic support
bjorn3 Aug 31, 2023
00022dd
Accept R and __R symbol prefixes
bjorn3 Aug 31, 2023
ea6fddf
Fix variable shadowing issue
bjorn3 Aug 31, 2023
ad63d9d
Update format of readme additions to match the rest
bjorn3 Sep 24, 2023
c911196
Rustfmt
bjorn3 Sep 24, 2023
fa8155b
clang-format
bjorn3 Sep 25, 2023
4847703
Decode UTF-8 from string literals, and allow escapes to differ in tests.
eddyb Sep 26, 2023
e43e214
test-harness: `#[ignore]` the OOM hazard half of `limit_output`.
eddyb Sep 26, 2023
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4 changes: 2 additions & 2 deletions README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -25,9 +25,9 @@ The current port status by category is:
* [[#26] v0: allow identifiers to start with a digit.](https://github.com/rust-lang/rustc-demangle/pull/26)
* [[#53] v0: replace `skip_*` methods with `print_*` methods in a "skip printing" mode.](https://github.com/rust-lang/rustc-demangle/pull/53)
* arguably backported to Rust, as the C port always took this approach
* `min_const_generics` constants (`bool`, `char`, negative signed integers)
* this arguably also includes `p` as an *untyped* placeholder constant
* **(UNPORTED)** symbol prefix flexibility (`__R` and `R`, instead of `_R`)
* **(UNPORTED)** `min_const_generics` constants (`bool`, `char`, negative signed integers)
* this arguably also includes `p` as an *untyped* placeholder constant
* **(UNPORTED)** [`str` and structural constants](https://github.com/rust-lang/rfcs/pull/3161)
(only usable in `const` generics on unstable Rust)
* **(UNPORTED)** recursion limits
Expand Down
234 changes: 209 additions & 25 deletions rust-demangle.c
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Original file line number Diff line number Diff line change
Expand Up @@ -182,6 +182,60 @@ static void print_uint64_hex(struct rust_demangler *rdm, uint64_t x) {
PRINT(s);
}

static void print_quoted_escaped_char(struct rust_demangler *rdm, char quote, uint32_t c) {
switch (c) {
case '\0':
PRINT("\\0");
break;

case '\t':
PRINT("\\t");
break;

case '\r':
PRINT("\\r");
break;

case '\n':
PRINT("\\n");
break;

case '\\':
PRINT("\\\\");
break;

case '"':
if (quote == '"') {
PRINT("\\\"");
} else {
PRINT("\"");
}
break;

case '\'':
if (quote == '\'') {
PRINT("\\'");
} else {
PRINT("'");
}
break;

default:
if (c >= 0x20 && c <= 0x7e) {
// Printable ASCII
char v = (char)c;
print_str(rdm, &v, 1);
} else {
// FIXME show printable unicode characters without hex encoding
PRINT("\\u{");
char s[9] = {0};
sprintf(s, "%" PRIx32, c);
PRINT(s);
PRINT("}");
}
}
}

static void
print_ident(struct rust_demangler *rdm, struct rust_mangled_ident ident) {
if (rdm->errored || rdm->skipping_printing)
Expand Down Expand Up @@ -342,8 +396,9 @@ static void demangle_generic_arg(struct rust_demangler *rdm);
static void demangle_type(struct rust_demangler *rdm);
static bool demangle_path_maybe_open_generics(struct rust_demangler *rdm);
static void demangle_dyn_trait(struct rust_demangler *rdm);
static void demangle_const(struct rust_demangler *rdm);
static void demangle_const_uint(struct rust_demangler *rdm);
static void demangle_const(struct rust_demangler *rdm, bool in_value);
static void demangle_const_uint(struct rust_demangler *rdm, char ty_tag);
static void demangle_const_str_literal(struct rust_demangler *rdm);

/// Optionally enter a binder ('G') for late-bound lifetimes,
/// printing e.g. `for<'a, 'b> `, and make those lifetimes visible
Expand Down Expand Up @@ -470,7 +525,7 @@ static void demangle_generic_arg(struct rust_demangler *rdm) {
uint64_t lt = parse_integer_62(rdm);
print_lifetime_from_index(rdm, lt);
} else if (eat(rdm, 'K'))
demangle_const(rdm);
demangle_const(rdm, false);
else
demangle_type(rdm);
}
Expand Down Expand Up @@ -566,7 +621,7 @@ static void demangle_type(struct rust_demangler *rdm) {
demangle_type(rdm);
if (tag == 'A') {
PRINT("; ");
demangle_const(rdm);
demangle_const(rdm, true);
}
PRINT("]");
break;
Expand Down Expand Up @@ -732,45 +787,138 @@ static void demangle_dyn_trait(struct rust_demangler *rdm) {
PRINT(">");
}

static void demangle_const(struct rust_demangler *rdm) {
static void demangle_const(struct rust_demangler *rdm, bool in_value) {
CHECK_OR(!rdm->errored, return );

if (eat(rdm, 'B')) {
size_t backref = parse_integer_62(rdm);
if (!rdm->skipping_printing) {
size_t old_next = rdm->next;
rdm->next = backref;
demangle_const(rdm);
rdm->next = old_next;
}
return;
}
bool opened_brace = false;

char ty_tag = next(rdm);
switch (ty_tag) {
case 'p':
PRINT("_");
break;

// Unsigned integer types.
case 'h':
case 't':
case 'm':
case 'y':
case 'o':
case 'j':
demangle_const_uint(rdm, ty_tag);
break;

case 'a':
case 's':
case 'l':
case 'x':
case 'n':
case 'i':
if (eat(rdm, 'n')) {
PRINT("-");
}
demangle_const_uint(rdm, ty_tag);
break;

case 'b': {
uint64_t value = 0;
size_t hex_len = 0;
while (!eat(rdm, '_')) {
value <<= 4;

char c = next(rdm);
if (IS_DIGIT(c))
value |= c - '0';
else if (c >= 'a' && c <= 'f')
value |= 10 + (c - 'a');
else
ERROR_AND(return );
hex_len++;
}

if (value == 0) {
PRINT("false");
} else if (value == 1) {
PRINT("true");
} else {
ERROR_AND(return );
}
break;
}
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@eddyb eddyb Sep 24, 2023

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Don't we require b0_ and b1_? Oh, no, we don't, that got changed with try_parse_uint.
And demangle_const_uint doesn't have a try_parse_uint because of how it handles hex fallback, ugh.


case 'c': {
uint64_t value = 0;
size_t hex_len = 0;
while (!eat(rdm, '_')) {
value <<= 4;

char c = next(rdm);
if (IS_DIGIT(c))
value |= c - '0';
else if (c >= 'a' && c <= 'f')
value |= 10 + (c - 'a');
else
ERROR_AND(return );
hex_len++;
}

if (value >= 0x10FFFF)
ERROR_AND(return );

if (value >= 0xD800 && value <= 0xDFFF)
ERROR_AND(return );

PRINT("'");
print_quoted_escaped_char(rdm, '\'', value);
PRINT("'");

break;
}

case 'e':
if (!in_value) {
opened_brace = true;
PRINT("{");
}
PRINT("*");

demangle_const_str_literal(rdm);
break;

case 'R':
case 'Q':
ERROR_AND(return ); // FIXME

case 'A':
ERROR_AND(return ); // FIXME

case 'T':
ERROR_AND(return ); // FIXME

case 'V':
ERROR_AND(return ); // FIXME

case 'B': {
size_t backref = parse_integer_62(rdm);
if (!rdm->skipping_printing) {
size_t old_next = rdm->next;
rdm->next = backref;
demangle_const(rdm, in_value);
rdm->next = old_next;
}
break;
}

default:
ERROR_AND(return );
}

if (eat(rdm, 'p'))
PRINT("_");
else {
demangle_const_uint(rdm);
if (rdm->verbose)
PRINT(basic_type(ty_tag));
if (opened_brace) {
PRINT("}");
}
}

static void demangle_const_uint(struct rust_demangler *rdm) {
static void demangle_const_uint(struct rust_demangler *rdm, char ty_tag) {
CHECK_OR(!rdm->errored, return );

uint64_t value = 0;
Expand All @@ -791,11 +939,47 @@ static void demangle_const_uint(struct rust_demangler *rdm) {
// Print anything that doesn't fit in `uint64_t` verbatim.
if (hex_len > 16) {
PRINT("0x");
print_str(rdm, rdm->sym + (rdm->next - hex_len), hex_len);
return;
print_str(rdm, rdm->sym + (rdm->next - hex_len - 1), hex_len);
} else {
print_uint64(rdm, value);
}

if (rdm->verbose)
PRINT(basic_type(ty_tag));
}


static void demangle_const_str_literal(struct rust_demangler *rdm) {
CHECK_OR(!rdm->errored, return );

PRINT("\"");

// FIXME(bjorn3) actually decode UTF-8 strings into individual characters
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@eddyb eddyb Sep 24, 2023

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What's kind of funny is that 1. try_parse_str_chars in the Rust version barely and 2. there's a UTF-8 encoder somewhere in this file, for punycode, so I feel like combining the two (the encoder giving you the mapping of the bits to bytes) might not even be that hard. And we have test data, so I can golf it if you want.

while (!eat(rdm, '_')) {
uint32_t value = 0;

char c = next(rdm);
if (IS_DIGIT(c))
value |= c - '0';
else if (c >= 'a' && c <= 'f')
value |= 10 + (c - 'a');
else
ERROR_AND(return );

value <<= 4;

c = next(rdm);
if (IS_DIGIT(c))
value |= c - '0';
else if (c >= 'a' && c <= 'f')
value |= 10 + (c - 'a');
else
ERROR_AND(return );

print_quoted_escaped_char(rdm, '"', value);
}

print_uint64(rdm, value);
PRINT("\"");
}

bool rust_demangle_with_callback(
Expand Down
15 changes: 13 additions & 2 deletions test-harness/tests/v0.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -106,16 +106,27 @@ fn demangle_min_const_generics() {
t_const!("c76_", "'v'");
t_const!("c22_", r#"'"'"#);
t_const!("ca_", "'\\n'");
t_const!("c2202_", "'∂'");
}

// FIXME(eddyb) port the relevant functionality to C.
// FIXME(bjorn3) port the relevant functionality to C.
#[should_panic]
#[test]
fn demangle_min_const_generics_unicode() {
t_const!("c2202_", "'∂'");
}

#[test]
fn demangle_const_str() {
t_const!("e616263_", "{*\"abc\"}");
t_const!("e27_", r#"{*"'"}"#);
t_const!("e090a_", "{*\"\\t\\n\"}");

}

// FIXME(bjorn3) port the relevant functionality to C.
#[should_panic]
#[test]
fn demangle_const_str_unicode() {
t_const!("ee28882c3bc_", "{*\"∂ü\"}");
t_const!(
"ee183a1e18390e183ade1839be18394e1839ae18390e183935fe18392e18394e1839b\
Expand Down