Changeset 172777 in webkit for trunk/Source/JavaScriptCore/offlineasm/settings.rb

Timestamp:

Aug 19, 2014, 4:25:37 PM (11 years ago)

Author:

[email protected]

Message:

LLInt build should be way faster
​https://bugs.webkit.org/show_bug.cgi?id=136085

Reviewed by Geoffrey Garen.

This does three things to improve the LLInt build performance. One of them is only for
Xcode for now while the others should benefit all platforms:

• Don't exponentially build settings combinations that correspond to being on two backends simultaneously. This is by far the biggest win.

• Don't generate offset extraction code for backends that aren't supported by the current port. This currently only works on Xcode-based ports. This is a relatively small win.

• Remove the ALWAYS_ALLOCATE_SLOW option. Each option increases build time, and we haven't used this one in a long time. Anyway, setting this option could be emulated by just directly hacking the code.

This is an enormous speed-up in the LLInt build.

• JavaScriptCore.xcodeproj/project.pbxproj: Prune the set of backends that we should consider on Xcode-based platforms.
• llint/LLIntOfflineAsmConfig.h: Remove ALWAYS_ALLOCATE_SLOW
• llint/LowLevelInterpreter.asm: Remove ALWAYS_ALLOCATE_SLOW
• offlineasm/backends.rb: Add infrastructure for reasoning about valid backends.
• offlineasm/generate_offset_extractor.rb: Allow the client to specify a filtered set of valid backends.
• offlineasm/settings.rb: Improve the construction of settings combinations so that it doesn't traverse the enourmous set of obviously invalid multi-backend combinations. Also glue into support for valid backends.

File:

• trunk/Source/JavaScriptCore/offlineasm/settings.rb (modified) (2 diffs)

trunk/Source/JavaScriptCore/offlineasm/settings.rb

@@ -55 +55 @@
     end
     
-    settingsCombinator(settingsCombinations, {}, (ast.filter(Setting).uniq.collect{|v| v.name} + BACKENDS).uniq)
+    nonBackendSettings = ast.filter(Setting).uniq.collect{ |v| v.name }
+    nonBackendSettings.delete_if {
+        | setting |
+        isBackend? setting
+    }
+    
+    allBackendsFalse = {}
+    BACKENDS.each {
+        | backend |
+        allBackendsFalse[backend] = false
+    }
+    
+    # This will create entries for invalid backends. That's fine. It's necessary
+    # because it ensures that generate_offsets_extractor (which knows about valid
+    # backends) has settings indices that are compatible with what asm will see
+    # (asm doesn't know about valid backends).
+    BACKENDS.each {
+        | backend |
+        map = allBackendsFalse.clone
+        map[backend] = true
+        settingsCombinator(settingsCombinations, map, nonBackendSettings)
+    }
     
     settingsCombinations
@@ -74 +95 @@
     BACKENDS.each {
         | backend |
-        isSupported = concreteSettings[backend]
-        raise unless isSupported != nil
-        numClaimedBackends += if isSupported then 1 else 0 end
-        if isSupported
+        if concreteSettings[backend]
+            raise if selectedBackend
             selectedBackend = backend
         end
     }
     
-    return if numClaimedBackends > 1
+    return unless isValidBackend? selectedBackend
     
     # Resolve the AST down to a low-level form (no macros or conditionals).