* pkg/proc: convert freebsd ptrace code to cgo
There is little point in having cgo call a custom C function, when the same
can be done directly from cgo (with less code and effort). Split the amd64
specific code into ptrace_freebsd_amd64.go. Also avoid mixing C.ptrace()
with syscall.SYS_PTRACE.
This will make further changes easier - no functional change intended.
* pkg/proc: check return values of ptrace calls on freebsd
The return values of the PT_GETNUMLWPS and PT_GETLWPLIST ptrace calls were
previously unchecked. While these should not fail, panic instead of using
-1 with slice allocation/handling.
* pkg/proc: return *amd64util.AMD64Xstate from freebsd ptraceGetRegset
Return a pointer to a struct, rather than a struct - this simplifies the
code in both the caller and the ptraceGetRegset function, while also avoiding
struct copying.
* pkg/proc: fix floating point register setting on freebsd
The original code could never work - PT_SETREGS on freebsd does not
take an iovec, nor does it set FP registers. Furthermore, the xsave
bytes were not stored in the amd64util.AMD64Xstate struct.
Updates #3001
* pkg/proc: re-enable function call injection on freebsd
Floating point registers can now be set and restored correctly.
This is a partial revert of 51090f003bace1f8cc37b8480ffdb6f6cc91fa5a.
Fixes#3001
* pkg/proc: deduplicate register setting code on freebsd
Delve represents registerized variables (fully or partially) using
compositeMemory, implementing proc.(*compositeMemory).WriteMemory is
necessary to make SetVariable and function calls work when Go will
switch to using the register calling convention in 1.17.
This commit also makes some refactoring by moving the code that
converts between register numbers and register names out of pkg/proc
into a different package.
Changes implementations of proc.Registers interface and the
op.DwarfRegisters struct so that floating point registers can be loaded
only when they are needed.
Removes the floatingPoint parameter from proc.Thread.Registers.
This accomplishes three things:
1. it simplifies the proc.Thread.Registers interface
2. it makes it impossible to accidentally create a broken set of saved
registers or of op.DwarfRegisters by accidentally calling
Registers(false)
3. it improves general performance of Delve by avoiding to load
floating point registers as much as possible
Floating point registers are loaded under two circumstances:
1. When the Slice method is called with floatingPoint == true
2. When the Copy method is called
Benchmark before:
BenchmarkConditionalBreakpoints-4 1 4327350142 ns/op
Benchmark after:
BenchmarkConditionalBreakpoints-4 1 3852642917 ns/op
Updates #1549
