From: Sam Clegg <sbc@chromium.org>
Date: Tue, 13 Jun 2017 01:42:21 +0000 (+0000)
Subject: [WebAssembly] Fix symbol type for addresses of external functions
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=cbf4a3dfadbedd488b125a835f5d627bb1fe282b;p=llvm

[WebAssembly] Fix symbol type for addresses of external functions

These symbols were previously not being marked as functions
so were appearing as globals instead, and with the incorrect
relocation type.

Without this fix, objects that take address of external
functions include them as global imports rather than function
imports which then fails at link time.

Differential Revision: https://reviews.llvm.org/D34068

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305263 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Target/WebAssembly/WebAssemblyAsmPrinter.cpp b/lib/Target/WebAssembly/WebAssemblyAsmPrinter.cpp
index 4178ec0b28f..b999091e2d2 100644
--- a/lib/Target/WebAssembly/WebAssemblyAsmPrinter.cpp
+++ b/lib/Target/WebAssembly/WebAssemblyAsmPrinter.cpp
@@ -33,6 +33,8 @@
 #include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCStreamer.h"
 #include "llvm/MC/MCSymbol.h"
+#include "llvm/MC/MCSymbolWasm.h"
+#include "llvm/MC/MCSymbolELF.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/TargetRegistry.h"
 #include "llvm/Support/raw_ostream.h"
@@ -218,9 +220,13 @@ void WebAssemblyAsmPrinter::EmitInstruction(const MachineInstr *MI) {
 
 const MCExpr *WebAssemblyAsmPrinter::lowerConstant(const Constant *CV) {
   if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV))
-    if (GV->getValueType()->isFunctionTy())
+    if (GV->getValueType()->isFunctionTy()) {
+      MCSymbol* Sym = getSymbol(GV);
+      if (!isa<MCSymbolELF>(Sym))
+        cast<MCSymbolWasm>(Sym)->setIsFunction(true);
       return MCSymbolRefExpr::create(
-          getSymbol(GV), MCSymbolRefExpr::VK_WebAssembly_FUNCTION, OutContext);
+          Sym, MCSymbolRefExpr::VK_WebAssembly_FUNCTION, OutContext);
+    }
   return AsmPrinter::lowerConstant(CV);
 }
 
diff --git a/test/MC/WebAssembly/external-data.ll b/test/MC/WebAssembly/external-data.ll
index 91e05b3f13a..6914736ac67 100644
--- a/test/MC/WebAssembly/external-data.ll
+++ b/test/MC/WebAssembly/external-data.ll
@@ -2,10 +2,10 @@
 ; Verify relocations are correctly generated for addresses of externals
 ; in the data section.
 
-declare i32 @f1(...)
+@myimport = external global i32, align 4
 
 @foo = global i64 7, align 4
-@far = local_unnamed_addr global i32 (...)* @f1, align 4
+@bar = hidden global i32* @myimport, align 4
 
 ; CHECK:   - Type:            DATA
 ; CHECK:     Relocations:
diff --git a/test/MC/WebAssembly/external-func-address.ll b/test/MC/WebAssembly/external-func-address.ll
new file mode 100644
index 00000000000..4022b2c9bae
--- /dev/null
+++ b/test/MC/WebAssembly/external-func-address.ll
@@ -0,0 +1,25 @@
+; RUN: llc -mtriple wasm32-unknown-unknown-wasm -filetype=obj %s -o - | obj2yaml | FileCheck %s
+; Verify that addresses of external functions generate correctly typed
+; imports and relocations or type R_TABLE_INDEX_I32.
+
+declare void @f1() #1
+@ptr_to_f1 = hidden global void ()* @f1, align 4
+
+
+; CHECK:   - Type:            IMPORT
+; CHECK:     Imports:
+; CHECK:       - Module:          env
+; CHECK:         Field:           f1
+; CHECK:         Kind:            FUNCTION
+; CHECK:         SigIndex:        0
+; CHECK:   - Type:            ELEM
+; CHECK:     Segments:
+; CHECK:       - Offset:
+; CHECK:           Opcode:          I32_CONST
+; CHECK:           Value:           0
+; CHECK:         Functions:       [ 0 ]
+; CHECK:   - Type:            DATA
+; CHECK:     Relocations:
+; CHECK:       - Type:            R_WEBASSEMBLY_TABLE_INDEX_I32
+; CHECK:         Index:           0
+; CHECK:         Offset:          0x00000006