[PATCH] D104495: [lld][WebAssembly] Fix crash calling weakly undefined function in PIC code

[Sam Clegg via Phabricator via llvm-commits]

sbc100 created this revision.
Herald added subscribers: wingo, ecnelises, sunfish, jgravelle-google, dschuff.
sbc100 requested review of this revision.
Herald added subscribers: llvm-commits, aheejin.
Herald added a project: LLVM.

Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D104495

Files:
  lld/test/wasm/weak-undefined-pic.s
  lld/wasm/InputChunks.cpp
  lld/wasm/Writer.cpp


Index: lld/wasm/Writer.cpp
===================================================================
--- lld/wasm/Writer.cpp
+++ lld/wasm/Writer.cpp
@@ -546,7 +546,7 @@
 static bool shouldImport(Symbol *sym) {
   if (!sym->isUndefined())
     return false;
-  if (sym->isWeak() && !config->relocatable)
+  if (sym->isWeak() && !config->relocatable && !config->isPic)
     return false;
   if (!sym->isLive())
     return false;
Index: lld/wasm/InputChunks.cpp
===================================================================
--- lld/wasm/InputChunks.cpp
+++ lld/wasm/InputChunks.cpp
@@ -106,13 +106,12 @@
 
   for (const WasmRelocation &rel : relocations) {
     uint8_t *loc = buf + rel.Offset - inputSectionOffset;
-    auto value = file->calcNewValue(rel, tombstone, this);
     LLVM_DEBUG(dbgs() << "apply reloc: type=" << relocTypeToString(rel.Type));
     if (rel.Type != R_WASM_TYPE_INDEX_LEB)
       LLVM_DEBUG(dbgs() << " sym=" << file->getSymbols()[rel.Index]->getName());
     LLVM_DEBUG(dbgs() << " addend=" << rel.Addend << " index=" << rel.Index
-                      << " value=" << value << " offset=" << rel.Offset
-                      << "\n");
+                      << " offset=" << rel.Offset << "\n");
+    auto value = file->calcNewValue(rel, tombstone, this);
 
     switch (rel.Type) {
     case R_WASM_TYPE_INDEX_LEB:
Index: lld/test/wasm/weak-undefined-pic.s
===================================================================
--- lld/test/wasm/weak-undefined-pic.s
+++ lld/test/wasm/weak-undefined-pic.s
@@ -22,6 +22,7 @@
 _start:
   .functype _start () -> ()
   call get_foo_addr
+  call foo
   end_function
 
 .weak foo
@@ -75,7 +76,10 @@
 # RUN: obj2yaml %t3.wasm | FileCheck %s --check-prefix=IMPORT
 
 #      IMPORT:  - Type:            IMPORT
-#      IMPORT:      - Module:          GOT.func
+#      IMPORT:        Field:           foo
+# IMPORT-NEXT:        Kind:            FUNCTION
+# IMPORT-NEXT:        SigIndex:        0
+# IMPORT-NEXT:      - Module:          GOT.func
 # IMPORT-NEXT:        Field:           foo
 # IMPORT-NEXT:        Kind:            GLOBAL
 # IMPORT-NEXT:        GlobalType:      I32


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