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Add Parser::match_imm8 for parsing signed 8-bit integers

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Also, make some stylistic tweaks to `match_imm16` and `match_imm32` based on the review comments.
This commit is contained in:
Andrew Brown
2020-03-30 12:27:21 -07:00
parent 508042101f
commit 07fc9d33bd
1 changed files with 81 additions and 28 deletions
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109
cranelift/reader/src/parser.rs
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@@ -683,6 +683,49 @@ impl<'a> Parser<'a> {
}
}
// Match and consume an i8 immediate.
fn match_imm8(&mut self, err_msg: &str) -> ParseResult<i8> {
if let Some(Token::Integer(text)) = self.token() {
self.consume();
let negative = text.starts_with('-');
let positive = text.starts_with('+');
let text = if negative || positive {
// Strip sign prefix.
&text[1..]
} else {
text
};
// Parse the text value; the lexer gives us raw text that looks like an integer.
let value = if text.starts_with("0x") {
// Skip underscores.
let text = text.replace("_", "");
// Parse it as a i8 in hexadecimal form.
u8::from_str_radix(&text[2..], 16)
.map_err(|_| self.error("unable to parse i8 as a hexadecimal immediate"))?
} else {
// Parse it as a i8 to check for overflow and other issues.
text.parse()
.map_err(|_| self.error("expected i8 decimal immediate"))?
};
// Apply sign if necessary.
let signed = if negative {
let value = value.wrapping_neg() as i8;
if value > 0 {
return Err(self.error("negative number too small"));
}
value
} else {
value as i8
};
Ok(signed)
} else {
err!(self.loc, err_msg)
}
}
// Match and consume a signed 16-bit immediate.
fn match_imm16(&mut self, err_msg: &str) -> ParseResult<i16> {
if let Some(Token::Integer(text)) = self.token() {
@@ -695,27 +738,32 @@ impl<'a> Parser<'a> {
} else {
text
};
let mut value;
// Lexer just gives us raw text that looks like an integer.
if text.starts_with("0x") {
// Parse the text value; the lexer gives us raw text that looks like an integer.
let value = if text.starts_with("0x") {
// Skip underscores.
let text = text.replace("_", "");
// Parse it as a i16 in hexadecimal form.
value = u16::from_str_radix(&text[2..], 16)
.map_err(|_| self.error("unable to parse i16 as a hexadecimal immediate"))?;
u16::from_str_radix(&text[2..], 16)
.map_err(|_| self.error("unable to parse i16 as a hexadecimal immediate"))?
} else {
// Parse it as a i16 to check for overflow and other issues.
value = text
.parse()
.map_err(|_| self.error("expected i16 decimal immediate"))?;
}
if negative {
value = Ok(value.wrapping_neg())?;
if value as i16 > 0 {
text.parse()
.map_err(|_| self.error("expected i16 decimal immediate"))?
};
// Apply sign if necessary.
let signed = if negative {
let value = value.wrapping_neg() as i16;
if value > 0 {
return Err(self.error("negative number too small"));
}
}
Ok(value as i16)
value
} else {
value as i16
};
Ok(signed)
} else {
err!(self.loc, err_msg)
}
@@ -734,27 +782,32 @@ impl<'a> Parser<'a> {
} else {
text
};
let mut value;
// Lexer just gives us raw text that looks like an integer.
if text.starts_with("0x") {
// Parse the text value; the lexer gives us raw text that looks like an integer.
let value = if text.starts_with("0x") {
// Skip underscores.
let text = text.replace("_", "");
// Parse it as a i32 in hexadecimal form.
value = u32::from_str_radix(&text[2..], 16)
.map_err(|_| self.error("unable to parse i32 as a hexadecimal immediate"))?;
u32::from_str_radix(&text[2..], 16)
.map_err(|_| self.error("unable to parse i32 as a hexadecimal immediate"))?
} else {
// Parse it as a i32 to check for overflow and other issues.
value = text
.parse()
.map_err(|_| self.error("expected i32 decimal immediate"))?;
}
if negative {
value = Ok(value.wrapping_neg())?;
if value as i32 > 0 {
text.parse()
.map_err(|_| self.error("expected i32 decimal immediate"))?
};
// Apply sign if necessary.
let signed = if negative {
let value = value.wrapping_neg() as i32;
if value > 0 {
return Err(self.error("negative number too small"));
}
}
Ok(value as i32)
value
} else {
value as i32
};
Ok(signed)
} else {
err!(self.loc, err_msg)
}