Loop optimization: auto align elf64 loop targets (#72)

* Adding a better version of the C opt loop

* Add missing file

* Using test optimization and compilation for clang gcc

* Adding NOP to try loop aligned

* Update elf64.go

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Auto align jump targets

* Fix the govulncheck ci error

* Fix the for linter too (mix of C and go in sample/)

* Auto align so we don't need the manually aligned one

* Clean up a bit the code (#73)

* simplify minloop

* lint

* Use constants for nop and rex* and refactor code a bit

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: ldemailly

.github/workflows/gochecks.yml

@@ -27,7 +27,7 @@ jobs:
         if: matrix.os == 'ubuntu-latest'
         run: |
           go install golang.org/x/vuln/cmd/govulncheck@latest
-          govulncheck ./...
+          CGO_ENABLED=0 govulncheck ./...
       - name: Download linter config
         if: matrix.os == 'ubuntu-latest'
         run: curl -fsS -o .golangci.yml https://raw.githubusercontent.com/fortio/workflows/main/golangci.yml
@@ -36,6 +36,8 @@ jobs:
         uses: golangci/golangci-lint-action@1e7e51e771db61008b38414a730f564565cf7c20 # pin@v8
         with:
           version: v2.8.0
+        env:
+          CGO_ENABLED: 0
       - name: Run tests
         run: |
           go version

.gitignore

@@ -51,3 +51,4 @@ a.out.dSYM
 tiny_vm
 
 grol_cvm_debug
+*.s

Makefile

@@ -126,6 +126,8 @@ nativecloop: Makefile cvm/loop.c
 	time $(AOUT) # comment needed to avoid CreateProcess(NULL, time ./a.out, ...) failed.
 	$(CC) -O3 -Wall -Wextra -pedantic -Werror -DNOVOLATILE cvm/loop.c
 	time $(AOUT) # comment for windows
+	$(CC) -O3 -Wall -Wextra -pedantic -Werror -Wno-language-extension-token native/sample/minloop.c
+	time $(AOUT) # comment for windows
 
 elf64: vm
 	$(MAKE) -C native test-loop-native

asm/asm.go

@@ -318,9 +318,9 @@ func compile(elf64 bool, reader *bufio.Reader, writer *bufio.Writer) int {
 		args := fields[1:]
 		narg := len(args)
 		switch instr {
-		case "return":
+		case "nop", "return":
 			if narg != 0 {
-				return log.FErrf("Expecting 0 arguments for return, got %d (%v)", narg, args)
+				return log.FErrf("Expecting 0 arguments for %s, got %d (%v)", instr, narg, args)
 			}
 		case "var", "param", "sys", "syss": // one or more arguments
 			if narg == 0 {
@@ -420,6 +420,9 @@ func compile(elf64 bool, reader *bufio.Reader, writer *bufio.Writer) int {
 			}
 			log.Debugf("Param -> Defined parameters: %v", resolver.vars)
 			continue
+		case "nop":
+			data = false
+			op = op.SetOpcode(cpu.Nop)
 		case "return":
 			data = false
 			op = op.SetOpcode(cpu.Ret)