all: copy ABI Headers (#147)

This change copies `abi_*.h` files and adjusts `#include` compilier
directives for Bazel builds.

The files `abi_*.h` and `internal/fakecgo/abi_*.h` are the same because
Bazel does not support cross-package use of `#include` so we need
each one once per package. See also
bazel-contrib/rules_go#3636.

Closes #144

Signed-off-by: Eliott Bouhana <eliott.bouhana@datadoghq.com>

README.md

@@ -61,10 +61,13 @@ Purego uses code that originates from the Go runtime. These files are under the
 License that can be found [in the Go Source](https://github.com/golang/go/blob/master/LICENSE).
 This is a list of the copied files:
 
+* `abi_*.h` from package `runtime/cgo`
 * `zcallback_darwin_*.s` from package `runtime`
-* `internal/abi/abi_*.h` from package `runtime/cgo`
+* `internal/fakecgo/abi_*.h` from package `runtime/cgo`
 * `internal/fakecgo/asm_GOARCH.s` from package `runtime/cgo`
 * `internal/fakecgo/callbacks.go` from package `runtime/cgo`
 * `internal/fakecgo/go_GOOS_GOARCH.go` from package `runtime/cgo`
 * `internal/fakecgo/iscgo.go` from package `runtime/cgo`
-* `internal/fakecgo/setenv.go` from package `runtime/cgo`
+* `internal/fakecgo/setenv.go` from package `runtime/cgo
+
+The files `abi_*.h` and `internal/fakecgo/abi_*.h` are the same because Bazel does not support cross-package use of `#include` so we need each one once per package. (cf. [issue](https://github.com/bazelbuild/rules_go/issues/3636))

internal/fakecgo/abi_amd64.h

@@ -0,0 +1,99 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Macros for transitioning from the host ABI to Go ABI0.
+//
+// These save the frame pointer, so in general, functions that use
+// these should have zero frame size to suppress the automatic frame
+// pointer, though it's harmless to not do this.
+
+#ifdef GOOS_windows
+
+// REGS_HOST_TO_ABI0_STACK is the stack bytes used by
+// PUSH_REGS_HOST_TO_ABI0.
+#define REGS_HOST_TO_ABI0_STACK (28*8 + 8)
+
+// PUSH_REGS_HOST_TO_ABI0 prepares for transitioning from
+// the host ABI to Go ABI0 code. It saves all registers that are
+// callee-save in the host ABI and caller-save in Go ABI0 and prepares
+// for entry to Go.
+//
+// Save DI SI BP BX R12 R13 R14 R15 X6-X15 registers and the DF flag.
+// Clear the DF flag for the Go ABI.
+// MXCSR matches the Go ABI, so we don't have to set that,
+// and Go doesn't modify it, so we don't have to save it.
+#define PUSH_REGS_HOST_TO_ABI0()	\
+	PUSHFQ			\
+	CLD			\
+	ADJSP	$(REGS_HOST_TO_ABI0_STACK - 8)	\
+	MOVQ	DI, (0*0)(SP)	\
+	MOVQ	SI, (1*8)(SP)	\
+	MOVQ	BP, (2*8)(SP)	\
+	MOVQ	BX, (3*8)(SP)	\
+	MOVQ	R12, (4*8)(SP)	\
+	MOVQ	R13, (5*8)(SP)	\
+	MOVQ	R14, (6*8)(SP)	\
+	MOVQ	R15, (7*8)(SP)	\
+	MOVUPS	X6, (8*8)(SP)	\
+	MOVUPS	X7, (10*8)(SP)	\
+	MOVUPS	X8, (12*8)(SP)	\
+	MOVUPS	X9, (14*8)(SP)	\
+	MOVUPS	X10, (16*8)(SP)	\
+	MOVUPS	X11, (18*8)(SP)	\
+	MOVUPS	X12, (20*8)(SP)	\
+	MOVUPS	X13, (22*8)(SP)	\
+	MOVUPS	X14, (24*8)(SP)	\
+	MOVUPS	X15, (26*8)(SP)
+
+#define POP_REGS_HOST_TO_ABI0()	\
+	MOVQ	(0*0)(SP), DI	\
+	MOVQ	(1*8)(SP), SI	\
+	MOVQ	(2*8)(SP), BP	\
+	MOVQ	(3*8)(SP), BX	\
+	MOVQ	(4*8)(SP), R12	\
+	MOVQ	(5*8)(SP), R13	\
+	MOVQ	(6*8)(SP), R14	\
+	MOVQ	(7*8)(SP), R15	\
+	MOVUPS	(8*8)(SP), X6	\
+	MOVUPS	(10*8)(SP), X7	\
+	MOVUPS	(12*8)(SP), X8	\
+	MOVUPS	(14*8)(SP), X9	\
+	MOVUPS	(16*8)(SP), X10	\
+	MOVUPS	(18*8)(SP), X11	\
+	MOVUPS	(20*8)(SP), X12	\
+	MOVUPS	(22*8)(SP), X13	\
+	MOVUPS	(24*8)(SP), X14	\
+	MOVUPS	(26*8)(SP), X15	\
+	ADJSP	$-(REGS_HOST_TO_ABI0_STACK - 8)	\
+	POPFQ
+
+#else
+// SysV ABI
+
+#define REGS_HOST_TO_ABI0_STACK (6*8)
+
+// SysV MXCSR matches the Go ABI, so we don't have to set that,
+// and Go doesn't modify it, so we don't have to save it.
+// Both SysV and Go require DF to be cleared, so that's already clear.
+// The SysV and Go frame pointer conventions are compatible.
+#define PUSH_REGS_HOST_TO_ABI0()	\
+	ADJSP	$(REGS_HOST_TO_ABI0_STACK)	\
+	MOVQ	BP, (5*8)(SP)	\
+	LEAQ	(5*8)(SP), BP	\
+	MOVQ	BX, (0*8)(SP)	\
+	MOVQ	R12, (1*8)(SP)	\
+	MOVQ	R13, (2*8)(SP)	\
+	MOVQ	R14, (3*8)(SP)	\
+	MOVQ	R15, (4*8)(SP)
+
+#define POP_REGS_HOST_TO_ABI0()	\
+	MOVQ	(0*8)(SP), BX	\
+	MOVQ	(1*8)(SP), R12	\
+	MOVQ	(2*8)(SP), R13	\
+	MOVQ	(3*8)(SP), R14	\
+	MOVQ	(4*8)(SP), R15	\
+	MOVQ	(5*8)(SP), BP	\
+	ADJSP	$-(REGS_HOST_TO_ABI0_STACK)
+
+#endif

internal/fakecgo/abi_arm64.h

@@ -0,0 +1,39 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Macros for transitioning from the host ABI to Go ABI0.
+//
+// These macros save and restore the callee-saved registers
+// from the stack, but they don't adjust stack pointer, so
+// the user should prepare stack space in advance.
+// SAVE_R19_TO_R28(offset) saves R19 ~ R28 to the stack space
+// of ((offset)+0*8)(RSP) ~ ((offset)+9*8)(RSP).
+//
+// SAVE_F8_TO_F15(offset) saves F8 ~ F15 to the stack space
+// of ((offset)+0*8)(RSP) ~ ((offset)+7*8)(RSP).
+//
+// R29 is not saved because Go will save and restore it.
+
+#define SAVE_R19_TO_R28(offset) \
+	STP	(R19, R20), ((offset)+0*8)(RSP) \
+	STP	(R21, R22), ((offset)+2*8)(RSP) \
+	STP	(R23, R24), ((offset)+4*8)(RSP) \
+	STP	(R25, R26), ((offset)+6*8)(RSP) \
+	STP	(R27, g), ((offset)+8*8)(RSP)
+#define RESTORE_R19_TO_R28(offset) \
+	LDP	((offset)+0*8)(RSP), (R19, R20) \
+	LDP	((offset)+2*8)(RSP), (R21, R22) \
+	LDP	((offset)+4*8)(RSP), (R23, R24) \
+	LDP	((offset)+6*8)(RSP), (R25, R26) \
+	LDP	((offset)+8*8)(RSP), (R27, g) /* R28 */
+#define SAVE_F8_TO_F15(offset) \
+	FSTPD	(F8, F9), ((offset)+0*8)(RSP) \
+	FSTPD	(F10, F11), ((offset)+2*8)(RSP) \
+	FSTPD	(F12, F13), ((offset)+4*8)(RSP) \
+	FSTPD	(F14, F15), ((offset)+6*8)(RSP)
+#define RESTORE_F8_TO_F15(offset) \
+	FLDPD	((offset)+0*8)(RSP), (F8, F9) \
+	FLDPD	((offset)+2*8)(RSP), (F10, F11) \
+	FLDPD	((offset)+4*8)(RSP), (F12, F13) \
+	FLDPD	((offset)+6*8)(RSP), (F14, F15)

internal/fakecgo/asm_amd64.s

@@ -3,7 +3,7 @@
 // license that can be found in the LICENSE file.
 
 #include "textflag.h"
-#include "../abi/abi_amd64.h"
+#include "abi_amd64.h"
 
 // Called by C code generated by cmd/cgo.
 // func crosscall2(fn, a unsafe.Pointer, n int32, ctxt uintptr)

internal/fakecgo/asm_arm64.s

@@ -3,7 +3,7 @@
 // license that can be found in the LICENSE file.
 
 #include "textflag.h"
-#include "../abi/abi_arm64.h"
+#include "abi_arm64.h"
 
 // Called by C code generated by cmd/cgo.
 // func crosscall2(fn, a unsafe.Pointer, n int32, ctxt uintptr)

sys_amd64.s

@@ -4,7 +4,7 @@
 //go:build darwin || (!cgo && linux)
 
 #include "textflag.h"
-#include "internal/abi/abi_amd64.h"
+#include "abi_amd64.h"
 #include "go_asm.h"
 #include "funcdata.h"
 

sys_arm64.s

@@ -6,7 +6,6 @@
 #include "textflag.h"
 #include "go_asm.h"
 #include "funcdata.h"
-#include "internal/abi/abi_arm64.h"
 
 // syscall9X calls a function in libc on behalf of the syscall package.
 // syscall9X takes a pointer to a struct like:

sys_unix_arm64.s

@@ -6,7 +6,7 @@
 #include "textflag.h"
 #include "go_asm.h"
 #include "funcdata.h"
-#include "internal/abi/abi_arm64.h"
+#include "abi_arm64.h"
 
 TEXT callbackasm1(SB), NOSPLIT|NOFRAME, $0
 	NO_LOCAL_POINTERS