cmd/go: .swig/.swigcxx files now require SWIG 3.0.6 or later
cmd/vet: better validation of struct tags (https://golang.org/cl/2685)
cmd/ld: no longer record build timestamp in Windows PE file header (https://golang.org/cl/3740)
+cmd/go: add -toolexec build option
+cmd/go: drop -ccflags build option
+cmd/go: add -asmflags build option
+cmd/go: add -buildmode build option
+cmd/gc: add -dynlink option (for amd64 only)
+cmd/ld: add -buildmode option
cmd/trace: new command to view traces (https://golang.org/cl/3601)
Performance:
Assembler:
+New cmd/asm tool (now use go tool asm, not go tool 6a)
+
+Assembler now supports -dynlink option.
+
ARM assembly syntax has had some features removed.
- mentioning SP or PC as a hardware register