Changeset 220047 in webkit for trunk/Source/JavaScriptCore/offlineasm/parser.rb

Timestamp:

Jul 29, 2017, 8:01:12 PM (8 years ago)

Author:

[email protected]

Message:

LLInt offsets extractor should be able to handle C++ constexprs
​https://bugs.webkit.org/show_bug.cgi?id=174964

Reviewed by Saam Barati.

This patch adds new syntax to the offline asm language. The new keyword,
constexpr, takes the subsequent identifier and maps it to a C++ constexpr
expression. Additionally, if the value is not an identifier you can wrap it in
parentheses. e.g. constexpr (myConstexprFunction() + OBJECT_OFFSET(Foo, bar)),
which will get converted into:
static_cast<int64_t>(myConstexprFunction() + OBJECT_OFFSET(Foo, bar));

This patch also changes the data format the LLIntOffsetsExtractor
binary produces. Previously, it would produce unsigned values,
after this patch every value is an int64_t. Using an int64_t is
useful because it means that we can represent any constant needed.
int32_t masks are sign extended then passed then converted to a
negative literal sting in the assembler so it will be the constant
expected.

• llint/LLIntOffsetsExtractor.cpp:

(JSC::LLIntOffsetsExtractor::dummy):

• llint/LowLevelInterpreter.asm:
• llint/LowLevelInterpreter64.asm:
• offlineasm/asm.rb:
• offlineasm/ast.rb:
• offlineasm/generate_offset_extractor.rb:
• offlineasm/offsets.rb:
• offlineasm/parser.rb:
• offlineasm/transform.rb:

File:

• trunk/Source/JavaScriptCore/offlineasm/parser.rb (modified) (5 diffs)

trunk/Source/JavaScriptCore/offlineasm/parser.rb

@@ -4 +4 @@
 # modification, are permitted provided that the following conditions
 # are met:
-# 1. Redistributions of source code must retain the above copyright
+# 1. Redistributions of source code must retain the above copyrighht
 #    notice, this list of conditions and the following disclaimer.
 # 2. Redistributions in binary form must reproduce the above copyright
@@ -223 +223 @@
 
 def isKeyword(token)
-    token =~ /\A((true)|(false)|(if)|(then)|(else)|(elsif)|(end)|(and)|(or)|(not)|(global)|(macro)|(const)|(sizeof)|(error)|(include))\Z/ or
+    token =~ /\A((true)|(false)|(if)|(then)|(else)|(elsif)|(end)|(and)|(or)|(not)|(global)|(macro)|(const)|(constexpr)|(sizeof)|(error)|(include))\Z/ or
         token =~ REGISTER_PATTERN or
         isInstruction(token)
@@ -418 +418 @@
         [codeOrigin, names]
     end
+
+    def parseTextInParens
+        skipNewLine
+        codeOrigin = @tokens[@idx].codeOrigin
+        raise unless @tokens[@idx] == "("
+        @idx += 1
+        # need at least one item
+        raise if @tokens[@idx] == ")"
+        numEnclosedParens = 0
+        text = []
+        while @tokens[@idx] != ")" || numEnclosedParens > 0
+            if @tokens[@idx] == "("
+                numEnclosedParens += 1
+            elsif @tokens[@idx] == ")"
+                numEnclosedParens -= 1
+            end
+
+            text << @tokens[@idx].string
+            @idx += 1
+        end
+        @idx += 1
+        return [codeOrigin, text]
+    end
+
     
     def parseExpressionAtom
@@ -454 +478 @@
             codeOrigin, names = parseColonColon
             Sizeof.forName(codeOrigin, names.join('::'))
+        elsif @tokens[@idx] == "constexpr"
+            @idx += 1
+            skipNewLine
+            if @tokens[@idx] == "("
+                codeOrigin, text = parseTextInParens
+                text = text.join
+            else
+                codeOrigin, text = parseColonColon
+                text = text.join("::")
+            end
+            ConstExpr.forName(codeOrigin, text)
         elsif isLabel @tokens[@idx]
             result = LabelReference.new(@tokens[@idx].codeOrigin, Label.forName(@tokens[@idx].codeOrigin, @tokens[@idx].string))
@@ -482 +517 @@
     
     def couldBeExpression
-        @tokens[@idx] == "-" or @tokens[@idx] == "~" or @tokens[@idx] == "sizeof" or isInteger(@tokens[@idx]) or isString(@tokens[@idx]) or isVariable(@tokens[@idx]) or @tokens[@idx] == "("
+        @tokens[@idx] == "-" or @tokens[@idx] == "~" or @tokens[@idx] == "sizeof" or @tokens[@idx] == "constexpr" or isInteger(@tokens[@idx]) or isString(@tokens[@idx]) or isVariable(@tokens[@idx]) or @tokens[@idx] == "("
     end