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Avoid array lookups where simple constants are fine #35

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Merged
merged 2 commits into from
Mar 18, 2013
Merged

Avoid array lookups where simple constants are fine #35

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ba5d9d6
shift token type<->string mapping to CTFE/meta
DmitryOlshansky Mar 18, 2013
8d8d72d
fix a horrible perf mistake in genCaseTrie
DmitryOlshansky Mar 18, 2013
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5 changes: 5 additions & 0 deletions std/d/ast.d
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Original file line number Diff line number Diff line change
Expand Up @@ -74,6 +74,8 @@ class LabeledStatement : NonEmptyStatementNoCaseNoDefault
interface ExpressionStatement : NonEmptyStatementNoCaseNoDefault {}
interface DeclarationStatement : NonEmptyStatementNoCaseNoDefault {}

/+

/**
* $(LINK2 http://dlang.org/statement.html#IfStatement)
*/
Expand Down Expand Up @@ -395,3 +397,6 @@ class Inherits : DeclDef
//FunctionDeclaration[] functions;
}
+/


+/
22 changes: 14 additions & 8 deletions std/d/lexer.d
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Original file line number Diff line number Diff line change
Expand Up @@ -393,7 +393,6 @@ L_advance:
// since this branch at most is taken once per file
_empty = true;
return;
// pragma(msg, generateCaseTrie(
mixin(generateCaseTrie(
"=", "TokenType.assign",
"@", "TokenType.at",
Expand Down Expand Up @@ -485,7 +484,7 @@ L_advance:
if (!src.canPeek())
{
current.type = TokenType.dot;
current.value = getTokenValue(TokenType.dot);
current.value = tokenValue!(TokenType.dot);
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I'm surprised the optimizer didn't do this for us.

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Here he most likely did it, but see other cases where current.type is used.
Plus debug builds matter and there is dmd to care about ;)

return;
}
switch (src.peek())
Expand All @@ -501,13 +500,15 @@ L_advance:
{
current.type = TokenType.vararg;
nextCharNonLF();
current.value = tokenValue!(TokenType.vararg);
}
current.value = getTokenValue(current.type);
else
current.value = tokenValue!(TokenType.slice);
return;
default:
nextCharNonLF();
current.type = TokenType.dot;
current.value = getTokenValue(TokenType.dot);
current.value = tokenValue!(TokenType.dot);
return;
}
case '0': .. case '9':
Expand Down Expand Up @@ -1464,7 +1465,7 @@ L_advance:
else
{
current.type = TokenType.hash;
current.value = getTokenValue(TokenType.hash);
current.value = tokenValue!(TokenType.hash);
}
}

Expand Down Expand Up @@ -2705,6 +2706,11 @@ pure string getTokenValue(const TokenType type)
return tokenValues[type];
}

template tokenValue(TokenType val)
{
enum tokenValue = getTokenValue(val);
}

private pure bool isNewline(ubyte ch)
{
return ch == '\n' || ch == '\r';
Expand Down Expand Up @@ -2955,7 +2961,7 @@ string printCaseStatements(K, V)(TrieNode!(K,V) node, string indentString)
caseStatement ~= indentString;
caseStatement ~= "\t{\n";
caseStatement ~= indentString;
caseStatement ~= "\t\tcurrent.value = getTokenValue(current.type);\n";
caseStatement ~= "\t\tcurrent.value = tokenValue!("~node.children[k].value~");\n";
caseStatement ~= indentString;
caseStatement ~= "\t\tcurrent.type = " ~ node.children[k].value;
caseStatement ~= ";\n";
Expand All @@ -2975,7 +2981,7 @@ string printCaseStatements(K, V)(TrieNode!(K,V) node, string indentString)
caseStatement ~= v.value;
caseStatement ~= ";\n";
caseStatement ~= indentString;
caseStatement ~= "\t\tcurrent.value = getTokenValue(current.type);\n";
caseStatement ~= "\t\tcurrent.value = tokenValue!("~v.value~");\n";
caseStatement ~= indentString;
caseStatement ~= "\t\treturn;\n";
caseStatement ~= indentString;
Expand All @@ -2988,7 +2994,7 @@ string printCaseStatements(K, V)(TrieNode!(K,V) node, string indentString)
caseStatement ~= v.value;
caseStatement ~= ";\n";
caseStatement ~= indentString;
caseStatement ~= "\tcurrent.value = getTokenValue(current.type);\n";
caseStatement ~= "\tcurrent.value = tokenValue!("~v.value~");\n";
caseStatement ~= indentString;
caseStatement ~= "\treturn;\n";
}
Expand Down