Revert "Revert "runtime: consolidate function descriptor definitions on PPC64""

This reverts CL 481059, which in turn reverts CL 478917.

Reason for revert: reapply the original CL.

Change-Id: Icf6bb6a620313b44fadcc7f69a62fdbb943e34fd
Reviewed-on: https://go-review.googlesource.com/c/go/+/481075
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
Reviewed-by: Paul Murphy <murp@ibm.com>

diff --git a/src/runtime/asm_ppc64x.h b/src/runtime/asm_ppc64x.h
index cce5537a9cb59b7e060170a654d45099af13ff83..65870fe020fa3d40a7a8799aae567c79b629d464 100644 (file)
--- a/src/runtime/asm_ppc64x.h
+++ b/src/runtime/asm_ppc64x.h
@@ -24,16 +24,32 @@
 
 #define FIXED_FRAME 32
 
-// aix/ppc64 uses XCOFF which has function descriptors.
+// aix/ppc64 uses XCOFF which uses function descriptors.
+// AIX cannot perform the TOC relocation in a text section.
+// Therefore, these descriptors must live in a data section.
 #ifdef GOOS_aix
 #ifdef GOARCH_ppc64
 #define GO_PPC64X_HAS_FUNCDESC
+#define DEFINE_PPC64X_FUNCDESC(funcname, localfuncname)        \
+       DATA    funcname+0(SB)/8, $localfuncname(SB)    \
+       DATA    funcname+8(SB)/8, $TOC(SB)              \
+       DATA    funcname+16(SB)/8, $0                   \
+       GLOBL   funcname(SB), NOPTR, $24
 #endif
 #endif
 
-// linux/ppc64 uses ELFv1 which has function descriptors.
+// linux/ppc64 uses ELFv1 which uses function descriptors.
+// These must also look like ABI0 functions on linux/ppc64
+// to work with abi.FuncPCABI0(sigtramp) in os_linux.go.
+// Only static codegen is supported on linux/ppc64, so TOC
+// is not needed.
 #ifdef GOOS_linux
 #ifdef GOARCH_ppc64
 #define GO_PPC64X_HAS_FUNCDESC
+#define DEFINE_PPC64X_FUNCDESC(funcname, localfuncname)        \
+       TEXT    funcname(SB),NOSPLIT|NOFRAME,$0         \
+               DWORD   $localfuncname(SB)              \
+               DWORD   $0                              \
+               DWORD   $0
 #endif
 #endif

diff --git a/src/runtime/asm_ppc64x.s b/src/runtime/asm_ppc64x.s
index 7c866b4bc3367acdb71cf3fef8fe7092d14d3192..293683f41924c7390f2f296033b1a069c5db67a1 100644 (file)
--- a/src/runtime/asm_ppc64x.s
+++ b/src/runtime/asm_ppc64x.s
@@ -771,26 +771,11 @@ TEXT runtime·setg(SB), NOSPLIT, $0-8
        BL      runtime·save_g(SB)
        RET
 
-#ifdef GOARCH_ppc64
-#ifdef GOOS_aix
-DATA    setg_gcc<>+0(SB)/8, $_setg_gcc<>(SB)
-DATA    setg_gcc<>+8(SB)/8, $TOC(SB)
-DATA    setg_gcc<>+16(SB)/8, $0
-GLOBL   setg_gcc<>(SB), NOPTR, $24
+#ifdef GO_PPC64X_HAS_FUNCDESC
+DEFINE_PPC64X_FUNCDESC(setg_gcc<>, _setg_gcc<>)
+TEXT _setg_gcc<>(SB),NOSPLIT|NOFRAME,$0-0
 #else
 TEXT setg_gcc<>(SB),NOSPLIT|NOFRAME,$0-0
-       DWORD   $_setg_gcc<>(SB)
-       DWORD   $0
-       DWORD   $0
-#endif
-#endif
-
-// void setg_gcc(G*); set g in C TLS.
-// Must obey the gcc calling convention.
-#ifdef GOARCH_ppc64le
-TEXT setg_gcc<>(SB),NOSPLIT|NOFRAME,$0-0
-#else
-TEXT _setg_gcc<>(SB),NOSPLIT|NOFRAME,$0-0
 #endif
        // The standard prologue clobbers R31, which is callee-save in
        // the C ABI, so we have to use $-8-0 and save LR ourselves.

diff --git a/src/runtime/cgo/asm_ppc64x.s b/src/runtime/cgo/asm_ppc64x.s
index 8eb4a4215788656bbac898af8f8ffd2fbd36d67c..7752feb65047468c74f79e7d8c3b7b8f0a99e070 100644 (file)
--- a/src/runtime/cgo/asm_ppc64x.s
+++ b/src/runtime/cgo/asm_ppc64x.s
@@ -7,26 +7,25 @@
 #include "textflag.h"
 #include "asm_ppc64x.h"
 
+#ifdef GO_PPC64X_HAS_FUNCDESC
+// crosscall2 is marked with go:cgo_export_static. On AIX, this creates and exports
+// the symbol name and descriptor as the AIX linker expects, but does not work if
+// referenced from within Go. Create and use an aliased descriptor of crosscall2
+// to workaround this.
+DEFINE_PPC64X_FUNCDESC(_crosscall2<>, crosscall2)
+#define CROSSCALL2_FPTR $_crosscall2<>(SB)
+#else
+#define CROSSCALL2_FPTR $crosscall2(SB)
+#endif
+
 // Set the x_crosscall2_ptr C function pointer variable point to crosscall2.
 // It's such a pointer chain: _crosscall2_ptr -> x_crosscall2_ptr -> crosscall2
 TEXT ·set_crosscall2(SB),NOSPLIT,$0-0
        MOVD    _crosscall2_ptr(SB), R5
-#ifdef GOARCH_ppc64
-       MOVD    $_crosscall2<>(SB), R6
-#else
-       MOVD    $crosscall2(SB), R6
-#endif
+       MOVD    CROSSCALL2_FPTR, R6
        MOVD    R6, (R5)
        RET
 
-#ifdef GO_PPC64X_HAS_FUNCDESC
-// _crosscall2<> is a function descriptor to the real crosscall2.
-DATA    _crosscall2<>+0(SB)/8, $crosscall2(SB)
-DATA    _crosscall2<>+8(SB)/8, $TOC(SB)
-DATA    _crosscall2<>+16(SB)/8, $0
-GLOBL   _crosscall2<>(SB), NOPTR, $24
-#endif
-
 // Called by C code generated by cmd/cgo.
 // func crosscall2(fn, a unsafe.Pointer, n int32, ctxt uintptr)
 // Saves C callee-saved registers and calls cgocallback with three arguments.

diff --git a/src/runtime/rt0_aix_ppc64.s b/src/runtime/rt0_aix_ppc64.s
index 86fda5689967ab61b279261c811bb439471db8a4..1670a809862a2bdd0345171737804fa52112b2a4 100644 (file)
--- a/src/runtime/rt0_aix_ppc64.s
+++ b/src/runtime/rt0_aix_ppc64.s
@@ -3,13 +3,11 @@
 // license that can be found in the LICENSE file.
 
 #include "textflag.h"
+#include "asm_ppc64x.h"
 
 // _rt0_ppc64_aix is a function descriptor of the entrypoint function
 // __start. This name is needed by cmd/link.
-DATA   _rt0_ppc64_aix+0(SB)/8, $__start<>(SB)
-DATA   _rt0_ppc64_aix+8(SB)/8, $TOC(SB)
-GLOBL  _rt0_ppc64_aix(SB), NOPTR, $16
-
+DEFINE_PPC64X_FUNCDESC(_rt0_ppc64_aix, __start<>)
 
 // The starting function must return in the loader to
 // initialise some libraries, especially libthread which
@@ -37,11 +35,7 @@ TEXT __start<>(SB),NOSPLIT,$-8
        BL _main(SB)
 
 
-DATA   main+0(SB)/8, $_main(SB)
-DATA   main+8(SB)/8, $TOC(SB)
-DATA   main+16(SB)/8, $0
-GLOBL  main(SB), NOPTR, $24
-
+DEFINE_PPC64X_FUNCDESC(main, _main)
 TEXT _main(SB),NOSPLIT,$-8
        MOVD $runtime·rt0_go(SB), R12
        MOVD R12, CTR
@@ -181,10 +175,7 @@ done:
        MOVD    R0, LR
        RET
 
-DATA   _rt0_ppc64_aix_lib_go+0(SB)/8, $__rt0_ppc64_aix_lib_go(SB)
-DATA   _rt0_ppc64_aix_lib_go+8(SB)/8, $TOC(SB)
-DATA   _rt0_ppc64_aix_lib_go+16(SB)/8, $0
-GLOBL  _rt0_ppc64_aix_lib_go(SB), NOPTR, $24
+DEFINE_PPC64X_FUNCDESC(_rt0_ppc64_aix_lib_go, __rt0_ppc64_aix_lib_go)
 
 TEXT __rt0_ppc64_aix_lib_go(SB),NOSPLIT,$0
        MOVD    _rt0_ppc64_aix_lib_argc<>(SB), R3

diff --git a/src/runtime/rt0_linux_ppc64.s b/src/runtime/rt0_linux_ppc64.s
index c9300a9caf602f8b3863b0b15e621ddfe4fe0955..f527170ed2848a1cc236b37b2f69fc1c63175f22 100644 (file)
--- a/src/runtime/rt0_linux_ppc64.s
+++ b/src/runtime/rt0_linux_ppc64.s
@@ -3,17 +3,10 @@
 // license that can be found in the LICENSE file.
 
 #include "textflag.h"
+#include "asm_ppc64x.h"
 
-// actually a function descriptor for _main<>(SB)
-TEXT _rt0_ppc64_linux(SB),NOSPLIT,$0
-       DWORD $_main<>(SB)
-       DWORD $0
-       DWORD $0
-
-TEXT main(SB),NOSPLIT,$0
-       DWORD $_main<>(SB)
-       DWORD $0
-       DWORD $0
+DEFINE_PPC64X_FUNCDESC(_rt0_ppc64_linux, _main<>)
+DEFINE_PPC64X_FUNCDESC(main, _main<>)
 
 TEXT _main<>(SB),NOSPLIT,$-8
        // In a statically linked binary, the stack contains argc,

diff --git a/src/runtime/sys_linux_ppc64x.s b/src/runtime/sys_linux_ppc64x.s
index ec9b966c8c3c80594f38148bc2cc2224f5ae2f32..44cd0e7b3e57f51cf44d0d8c1c09bf96ba6b8faa 100644 (file)
--- a/src/runtime/sys_linux_ppc64x.s
+++ b/src/runtime/sys_linux_ppc64x.s
@@ -447,18 +447,16 @@ TEXT runtime·sigfwd(SB),NOSPLIT,$0-32
        MOVD    24(R1), R2
        RET
 
-#ifdef GOARCH_ppc64le
+#ifdef GO_PPC64X_HAS_FUNCDESC
+DEFINE_PPC64X_FUNCDESC(runtime·sigtramp, sigtramp<>)
+// cgo isn't supported on ppc64, but we need to supply a cgoSigTramp function.
+DEFINE_PPC64X_FUNCDESC(runtime·cgoSigtramp, sigtramp<>)
+TEXT sigtramp<>(SB),NOSPLIT|NOFRAME|TOPFRAME,$0
+#else
 // ppc64le doesn't need function descriptors
 // Save callee-save registers in the case of signal forwarding.
 // Same as on ARM64 https://golang.org/issue/31827 .
 TEXT runtime·sigtramp(SB),NOSPLIT|NOFRAME,$0
-#else
-// function descriptor for the real sigtramp
-TEXT runtime·sigtramp(SB),NOSPLIT|NOFRAME,$0
-       DWORD   $sigtramp<>(SB)
-       DWORD   $0
-       DWORD   $0
-TEXT sigtramp<>(SB),NOSPLIT|NOFRAME|TOPFRAME,$0
 #endif
        // Start with standard C stack frame layout and linkage.
        MOVD    LR, R0
@@ -627,7 +625,6 @@ TEXT sigtramp<>(SB),NOSPLIT|NOFRAME|TOPFRAME,$0
        RET
 
 #ifdef GOARCH_ppc64le
-// ppc64le doesn't need function descriptors
 TEXT runtime·cgoSigtramp(SB),NOSPLIT|NOFRAME,$0
        // The stack unwinder, presumably written in C, may not be able to
        // handle Go frame correctly. So, this function is NOFRAME, and we
@@ -722,14 +719,6 @@ sigtrampnog:
        MOVD    R12, CTR
        MOVD    R10, LR // restore LR
        JMP     (CTR)
-#else
-// function descriptor for the real sigtramp
-TEXT runtime·cgoSigtramp(SB),NOSPLIT|NOFRAME,$0
-       DWORD   $cgoSigtramp<>(SB)
-       DWORD   $0
-       DWORD   $0
-TEXT cgoSigtramp<>(SB),NOSPLIT,$0
-       JMP     sigtramp<>(SB)
 #endif
 
 // Used by cgoSigtramp to inspect without clobbering R30/R31 via runtime.load_g.