Fix dynamic linking on PPC64.
Dynamic linking on PPC64 has had problems since we had to move the top-down
hazard-detection logic post-ra. For dynamic linking to work there needs to be
a nop placed after every call. It turns out that it is really hard to guarantee
that nothing will be placed in between the call (bl) and the nop during post-ra
scheduling. Previous attempts at fixing this by placing logic inside the
hazard detector only partially worked.
This is now fixed in a different way: call+nop codegen-only instructions. As far
as CodeGen is concerned the pair is now a single instruction and cannot be split.
This solution works much better than previous attempts.
The scoreboard hazard detector is also renamed to be more generic, there is currently
no cpu-specific logic in it.
llvm-svn: 153816
diff --git a/llvm/lib/Target/PowerPC/PPCInstr64Bit.td b/llvm/lib/Target/PowerPC/PPCInstr64Bit.td
index 78f3596..e1d8b65 100644
--- a/llvm/lib/Target/PowerPC/PPCInstr64Bit.td
+++ b/llvm/lib/Target/PowerPC/PPCInstr64Bit.td
@@ -89,10 +89,22 @@
let Uses = [RM] in {
def BL8_ELF : IForm<18, 0, 1,
(outs), (ins calltarget:$func, variable_ops),
- "bl $func", BrB, []>; // See Pat patterns below.
+ "bl $func", BrB, []>; // See Pat patterns below.
+
+ let isCodeGenOnly = 1 in
+ def BL8_NOP_ELF : IForm_and_DForm_4_zero<18, 0, 1, 24,
+ (outs), (ins calltarget:$func, variable_ops),
+ "bl $func\n\tnop", BrB, []>;
+
def BLA8_ELF : IForm<18, 1, 1,
(outs), (ins aaddr:$func, variable_ops),
"bla $func", BrB, [(PPCcall_SVR4 (i64 imm:$func))]>;
+
+ let isCodeGenOnly = 1 in
+ def BLA8_NOP_ELF : IForm_and_DForm_4_zero<18, 1, 1, 24,
+ (outs), (ins aaddr:$func, variable_ops),
+ "bla $func\n\tnop", BrB,
+ [(PPCcall_nop_SVR4 (i64 imm:$func))]>;
}
let Uses = [X11, CTR8, RM] in {
def BCTRL8_ELF : XLForm_2_ext<19, 528, 20, 0, 1,
@@ -111,8 +123,14 @@
def : Pat<(PPCcall_SVR4 (i64 tglobaladdr:$dst)),
(BL8_ELF tglobaladdr:$dst)>;
+def : Pat<(PPCcall_nop_SVR4 (i64 tglobaladdr:$dst)),
+ (BL8_NOP_ELF tglobaladdr:$dst)>;
+
def : Pat<(PPCcall_SVR4 (i64 texternalsym:$dst)),
(BL8_ELF texternalsym:$dst)>;
+def : Pat<(PPCcall_nop_SVR4 (i64 texternalsym:$dst)),
+ (BL8_NOP_ELF texternalsym:$dst)>;
+
def : Pat<(PPCnop),
(NOP)>;