Merge branch 'JIT'

espruino · May 12, 2022 · b75a36a · b75a36a
2 parents 8291789 + 2914db8
commit b75a36a
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diff --git a/Makefile b/Makefile
@@ -641,6 +641,11 @@ ifeq ($(USE_TENSORFLOW),1)
 include make/misc/tensorflow.make
 endif
 
+ifeq ($(USE_JIT),1)
+  DEFINES += -DESPR_JIT
+  SOURCES += src/jsjit.c src/jsjitc.c
+endif
+
 
 endif # BOOTLOADER ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ DON'T USE STUFF ABOVE IN BOOTLOADER
 

diff --git a/README_JIT.md b/README_JIT.md
@@ -0,0 +1,158 @@
+Espruino JIT compiler
+======================
+
+This compiler allows Espruino to compile JS code into ARM Thumb code.
+
+Right now this roughly doubles execution speed.
+
+Works:
+
+* Assignments
+* Maths operators, postfix operators
+* Function calls
+* `for (;;)` loops
+* `if ()`
+* On the whole functions that can't be JITed will produce a message on the console and will be treated as normal functions.
+
+Doesn't work:
+
+* Everything else
+* Function arguments
+* `var/const/let`
+* Member access (with `.` or `[]`)
+
+Performance:
+
+* Right now, variable accesses search for the variable each time - so this is pretty slow. Maybe they could all be referenced at the start just once?
+* Built-in functions could be called directly, which would be a TON faster
+* Peephole optimisation could still be added (eg. removing `push r0, pop r0`) but this is the least of our worries
+* Stuff is in place to allow ints to be stored on the stack and converted when needed. This could maybe allow us to keep some vars as ints.
+
+Big stuff to do:
+
+* There seems to be a 'lock leak' - maybe on assignments
+* When calling a JIT function, using existing FunctionCall code to set up args and an execution scope (so args can be passed in)
+
+
+## Testing
+
+### Linux
+
+* Build for Linux `USE_JIT=1 DEBUG=1 make`
+* Test with `./espruino --test-jit` - doesn't do much useful right now
+* CLI test `./espruino -e 'function jit() {"jit";return 123;}'`
+* On Linux builds, a file `jit.bin` is created each time JIT runs. It contains the raw Thumb code.
+* Disassemble binary with `arm-none-eabi-objdump -D -Mforce-thumb -b binary -m cortex-m4 jit.bin`
+
+You can see what code is created with stuff like:
+
+```
+./espruino -e "E.setFlags({jitDebug:1});trace(function jit() {'jit';return 1+2;})"
+
+./espruino -e 'E.setFlags({jitDebug:1});function jit() {"jit";return "Hello"}'
+
+./espruino -e 'E.setFlags({jitDebug:1});function jit() {"jit";print(42)}'
+
+./espruino -e 'E.setFlags({jitDebug:1});function jit() {"jit";i=5}'
+
+./espruino -e 'E.setFlags({jitDebug:1});function jit() {"jit";if (i<3) print("T"); else print("X");}}'
+
+./espruino -e 'E.setFlags({jitDebug:1});function jit() {"jit";for (i=0;i<5;i=i+1) print(i);}'
+```
+
+
+### Raspberry Pi
+
+The Pi can execute Thumb-2 code (Pi 3 and on only)
+
+* Just build a normal Pi Binary on the Pi: `USE_JIT=1 DEBUG=1 make`
+* CLI test `./espruino -e 'function jit() {"jit";print("Hello World");};jit()'`
+* This may or may not work - sometimes it does (especially when launched from GDB) but I'm unsure why it's flakey!
+* Dump binary on pi with `objdump -D -Mforce-thumb -b binary -m arm jit.bin`
+
+### Build for an actual device
+
+* Build for ARM: `USE_JIT=1 BOARD=BOARD_NAME RELEASE=1 make flash`
+
+
+```
+// Enable debug output
+E.setFlags({jitDebug:1});
+
+
+function jit() {'jit';return 1;}
+jit()==1
+
+function jit() {'jit';return 1+2+3+4+5;}
+jit()==15
+
+function jit() {'jit';return 'Hello';}
+jit()=="Hello"
+
+function jit() {'jit';return true;}
+jit()==true
+
+var test = "Hello world";
+function jit() {'jit';return test;}
+jit()=="Hello world";
+
+var test = "Hello ";
+var jit = E.nativeCall(1, "JsVar()", E.JIT("test+'World!'"))
+jit()=="Hello World!"
+
+function t() { print("Hello"); }
+function jit() {'jit';t();}
+jit(); // prints 'hello'
+
+function jit() {'jit';print(42);}
+
+function jit() {'jit';print(42);return 123;}
+jit()==123
+
+function t() { return "Hello"; }
+function jit() {'jit'; return t()+" world";}
+jit()=="Hello world"
+
+function jit() {'jit';digitalWrite(LED1,1);}
+jit(); // LED on
+
+
+function jit() {'jit';i=42;}
+jit();i==42
+
+function jit() {'jit';return 1<2;}
+jit();i==true
+
+function jit() {"jit";if (i<3) print("T"); else print("X");print("--")}
+i=2;jit(); // prints T,--
+i=5;jit(); // prints X,--
+
+
+function jit() {"jit";for (i=0;i<5;i=i+1) print(i);}
+jit(); // prints 0,1,2,3,4
+
+function nojit() {for (i=0;i<1000;i=i+1);}
+function jit() {"jit";for (i=0;i<1000;i=i+1);}
+t=getTime();jit();getTime()-t // 0.14 sec
+t=getTime();nojit();getTime()-t // 0.28 sec
+```
+
+Run JIT on ARM and then disassemble:
+
+```
+// on ARM
+function jit() {"jit";return 1;}
+print(btoa(jit["\xffcod"]))
+
+// On Linux
+echo ASBL8Kz7AbQBvHBH | base64 -d  > jit.bin
+arm-none-eabi-objdump -D -Mforce-thumb -b binary -m cortex-m4 jit.bin
+```
+
+## Useful links
+
+
+http://www.cs.cornell.edu/courses/cs414/2001FA/armcallconvention.pdf
+https://developer.arm.com/documentation/ddi0308/d/Thumb-Instructions/Alphabetical-list-of-Thumb-instructions/B
+https://community.arm.com/arm-community-blogs/b/architectures-and-processors-blog/posts/condition-codes-1-condition-flags-and-codes
+
diff --git a/boards/RASPBERRYPI.py b/boards/RASPBERRYPI.py
@@ -17,7 +17,7 @@
 info = {
  'name' : "Raspberry Pi",
  'default_console' : "EV_USBSERIAL",
- 'variables' :  0, # 0 = resizable variables, rather than fixed
+ 'variables' :  5000, # 0 = resizable variables, rather than fixed
  'binary_name' : 'espruino_%v_raspberrypi',
  'build' : {
    'optimizeflags' : '-O3',
@@ -33,6 +33,7 @@
    'makefile' : [
      'LINUX=1',
      'DEFINES += -DRASPBERRYPI',
+     'DEFINES += -DJSVAR_MALLOC=1', # This is needed for JIT testing because otherwise we can't exec from the heap
    ]
  }
 };

diff --git a/src/jsflags.h b/src/jsflags.h
@@ -22,9 +22,13 @@ typedef enum {
   JSF_PRETOKENISE         = 1<<1, ///< When adding functions, pre-minify them and tokenise reserved words
   JSF_UNSAFE_FLASH        = 1<<2, ///< Some platforms stop writes/erases to interpreter memory to stop you bricking the device accidentally - this removes that protection
   JSF_UNSYNC_FILES        = 1<<3, ///< When accessing files, *don't* flush all data to the SD card after each command. Faster, but risky if power is lost
+#ifdef ESPR_JIT
+  JSF_JIT_DEBUG           = 1<<4, ///< When JIT enabled,
+#endif
 } PACKED_FLAGS JsFlags;
 
-#define JSFLAG_NAMES "deepSleep\0pretokenise\0unsafeFlash\0unsyncFiles\0"
+
+#define JSFLAG_NAMES "deepSleep\0pretokenise\0unsafeFlash\0unsyncFiles\0jitDebug\0"
 // NOTE: \0 also added by compiler - two \0's are required!
 
 extern volatile JsFlags jsFlags;