Commit f4435980fa2da335fe388db431d4a7946a99a2b9
2020-10-27T23:36:21
Power10 libffi fixes (#585) Power10 pc-relative code doesn't use or preserve r2 as a TOC pointer. That means calling between pc-relative and TOC using code can't be done without intervening linker stubs, and a call from TOC code to pc-relative code must have a nop after the bl in order to restore r2. Now the PowerPC libffi assembly code doesn't use r2 except for the implicit use when making calls back to C, ffi_closure_helper_LINUX64 and ffi_prep_args64. So changing the assembly to interoperate with pc-relative code without stubs is easily done. * src/powerpc/linux64.S (ffi_call_LINUX64): Don't emit global entry when __PCREL__. Call using @notoc. Add nops. * src/powerpc/linux64_closure.S (ffi_closure_LINUX64): Likewise. (ffi_go_closure_linux64): Likewise.
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diff --git a/src/powerpc/linux64.S b/src/powerpc/linux64.S
index c99889c..e92d64a 100644
--- a/src/powerpc/linux64.S
+++ b/src/powerpc/linux64.S
@@ -36,8 +36,10 @@
.cfi_startproc
# if _CALL_ELF == 2
ffi_call_LINUX64:
+# ifndef __PCREL__
addis %r2, %r12, .TOC.-ffi_call_LINUX64@ha
addi %r2, %r2, .TOC.-ffi_call_LINUX64@l
+# endif
.localentry ffi_call_LINUX64, . - ffi_call_LINUX64
# else
.section ".opd","aw"
@@ -89,9 +91,15 @@ ffi_call_LINUX64:
/* Call ffi_prep_args64. */
mr %r4, %r1
# if defined _CALL_LINUX || _CALL_ELF == 2
+# ifdef __PCREL__
+ bl ffi_prep_args64@notoc
+# else
bl ffi_prep_args64
+ nop
+# endif
# else
bl .ffi_prep_args64
+ nop
# endif
# if _CALL_ELF == 2
diff --git a/src/powerpc/linux64_closure.S b/src/powerpc/linux64_closure.S
index d67e4bb..3469a2c 100644
--- a/src/powerpc/linux64_closure.S
+++ b/src/powerpc/linux64_closure.S
@@ -37,8 +37,10 @@
.cfi_startproc
# if _CALL_ELF == 2
ffi_closure_LINUX64:
+# ifndef __PCREL__
addis %r2, %r12, .TOC.-ffi_closure_LINUX64@ha
addi %r2, %r2, .TOC.-ffi_closure_LINUX64@l
+# endif
.localentry ffi_closure_LINUX64, . - ffi_closure_LINUX64
# else
.section ".opd","aw"
@@ -190,11 +192,19 @@ ffi_closure_LINUX64:
# make the call
# if defined _CALL_LINUX || _CALL_ELF == 2
+# ifdef __PCREL__
+ bl ffi_closure_helper_LINUX64@notoc
+.Lret:
+# else
bl ffi_closure_helper_LINUX64
+.Lret:
+ nop
+# endif
# else
bl .ffi_closure_helper_LINUX64
-# endif
.Lret:
+ nop
+# endif
# now r3 contains the return type
# so use it to look up in a table
@@ -460,8 +470,10 @@ ffi_closure_LINUX64:
.cfi_startproc
# if _CALL_ELF == 2
ffi_go_closure_linux64:
+# ifndef __PCREL__
addis %r2, %r12, .TOC.-ffi_go_closure_linux64@ha
addi %r2, %r2, .TOC.-ffi_go_closure_linux64@l
+# endif
.localentry ffi_go_closure_linux64, . - ffi_go_closure_linux64
# else
.section ".opd","aw"