[clang] [llvm] [PowerPC] Support -fpatchable-function-entry (PR #92997)

[Fangrui Song via llvm-commits]

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@@ -0,0 +1,49 @@
+; RUN: llc -mtriple=powerpc-unknown-linux-gnu %s -o - | FileCheck %s --check-prefixes=CHECK,PPC32
+; RUN: llc -mtriple=powerpc64-unknown-linux-gnu %s -o - | FileCheck %s --check-prefixes=CHECK,PPC64
+
+define void @f0() {
+; CHECK-LABEL: f0:
+; CHECK-NOT:   nop
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    blr
+; CHECK-NOT:   .section    __patchable_function_entries
+  ret void
+}
+
+define void @f1() "patchable-function-entry"="0" {
+; CHECK-LABEL: f1:
+; CHECK-NOT:   nop
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    blr
+; CHECK-NOT:   .section    __patchable_function_entries
+  ret void
+}
+
+define void @f2() "patchable-function-entry"="1" {
+; CHECK-LABEL: f2:
+; CHECK-LABEL-NEXT:  .Lfunc_begin2:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    nop
+; CHECK-NEXT:    blr
+; CHECK:       .section    __patchable_function_entries
+; PPC32:       .p2align    2, 0x0
+; PPC64:       .p2align    3, 0x0
+; PPC32-NEXT:  .long   .Lfunc_begin2
+; PPC64-NEXT:  .quad   .Lfunc_begin2
+  ret void
+}
+
+define void @f3() "patchable-function-entry"="1" "patchable-function-prefix"="2" {
+; CHECK-LABEL: .Ltmp0:
+; CHECK-COUNT-2: nop
+; CHECK-LABEL: f3:
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MaskRay wrote:

Test addis/addi, instructions at the global entry point.

Per https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99888#c5 `#c8` and `#15`, GCC will change the current strategy to match us :)

https://github.com/llvm/llvm-project/pull/92997