[lld] Fix SEGFAULT in wasm-ld when importing wrapped symbol (PR #169656)

[Sam Clegg via llvm-commits]

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@@ -0,0 +1,36 @@
+# RUN: llvm-mc -filetype=obj -triple=wasm32-unknown-unknown %s -o %t.o
+# RUN: wasm-ld -emit-relocs -wrap nosuchsym -wrap foo -allow-undefined -o %t.wasm %t.o
+# RUN: obj2yaml %t.wasm | FileCheck %s
+
+.globl foo
+.globl _start
+
+foo:
+  .functype foo () -> (i32)
+  i32.const 1
+  end_function
+
+_start:
+  .functype _start () -> ()
+  call  foo
+  drop
+  end_function
+
+# CHECK:      - Type:            IMPORT
+# CHECK-NEXT:   Imports:
+# CHECK-NEXT:     - Module:          env
+# CHECK-NEXT:       Field:           __wrap_foo
+# CHECK-NEXT:       Kind:            FUNCTION
+# CHECK-NEXT        SigIndex:        0
+
+# CHECK:      - Type:            CODE
+# CHECK-NEXT:   Relocations:
+# CHECK-NEXT:     - Type:            R_WASM_FUNCTION_INDEX_LEB
+# CHECK-NEXT:       Index:           1
----------------
sbc100 wrote:

Is this the right value here for the relocation?  Shouldn't it be function zero (i.e. the __wrap_foo import) that is called here?   It is this index 1 in the symbol table?  If so you we should probably show the symbol table here too.  (or just drop the Relocations and emit-relocs flag completely?)

Could be a bug in --emit-relocs maybe?

https://github.com/llvm/llvm-project/pull/169656