[llvm] [BOLT][RISCV] Handle static IFUNC calls through .iplt (PR #207733)

[via llvm-commits]

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@@ -0,0 +1,46 @@
+## Check that BOLT recognizes a non-preemptible IFUNC IPLT entry and tracks an
+## otherwise unnamed resolver after the linker canonicalizes the exported IFUNC
+## symbol to the IPLT entry. Moving the containing function also verifies that
+## the IRELATIVE addend is updated to the resolver secondary entry, not the
+## primary function entry. Discard local symbols because LLD may retain a local
+## alias for the resolver.
+
+# RUN: llvm-mc -filetype=obj -triple=riscv64 -mattr=+relax -o %t.64.o %s
+# RUN: ld.lld -q -o %t.64 %t.64.o
+# RUN: llvm-objcopy --discard-all %t.64
+# RUN: llvm-bolt %t.64 -o %t.64.bolt --use-old-text=0 --lite=0 \
+# RUN:   --print-disasm --print-only=_start 2>&1 | FileCheck %s \
+# RUN:   --check-prefix=BOLT \
+# RUN:   --implicit-check-not="Expected BF to be presented as IFUNC resolver"
+# RUN: llvm-readelf -Wr -Ws %t.64.bolt | FileCheck %s --check-prefix=ELF
+# RUN: llvm-objdump -d --no-show-raw-insn %t.64.bolt \
+# RUN:   | FileCheck %s --check-prefix=IPLT
+
+# BOLT: Binary Function "_start
+# BOLT: auipc a0, %pcrel_hi(__ENTRY_func at 0x{{[0-9a-f]+}}@PLT)
+
+# ELF: R_RISCV_IRELATIVE {{ *}}[[#%x,RESOLVER:]]
+# ELF: {{0*}}[[#%x,RESOLVER-4]] 8 FUNC {{.*}} func
+
+# IPLT: Disassembly of section .iplt:
+# IPLT: <ifunc0>:
+# IPLT-NEXT: {{.*}} auipc t3,
+# IPLT-NEXT: {{.*}} ld t3,
+
+  .text
+  .globl _start
+  .type _start, @function
+_start:
+1:
+  auipc a0, %pcrel_hi(ifunc0)
+  addi a0, a0, %pcrel_lo(1b)
+
+  .globl func
+  .type func, @function
+func:
+  ret
+
+  .globl ifunc0
+  .type ifunc0, @gnu_indirect_function
+ifunc0:
+  ret
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Thrrreeee wrote:

Done.  This is caused by boundary-size issues.

https://github.com/llvm/llvm-project/pull/207733