[WebAssembly] Fixed objdump not parsing function headers.

Summary:
objdump was interpreting the function header containing the locals
declaration as instructions. To parse these without injecting target
specific code in objdump, MCDisassembler::onSymbolStart was added to
be implemented by the WebAssembly implemention.

WasmObjectFile now returns a code offset for the "address" of a symbol,
rather than the index. This is also more in-line with what other
targets do.

Also ensured that the AsmParser correctly puts each function
in its own segment to enable this test case.

Reviewers: sbc100, dschuff

Subscribers: jgravelle-google, aheejin, sunfish, rupprecht, llvm-commits

Differential Revision: https://reviews.llvm.org/D56684

llvm-svn: 351460

1 files changed, 6 insertions, 0 deletions

diff --git a/llvm/tools/llvm-objdump/llvm-objdump.cpp b/llvm/tools/llvm-objdump/llvm-objdump.cpp
index a4dbd07..7d0e7e9 100644
--- a/llvm/tools/llvm-objdump/llvm-objdump.cpp
+++ b/llvm/tools/llvm-objdump/llvm-objdump.cpp
@@ -1605,6 +1605,12 @@ static void disassembleObject(const ObjectFile *Obj, bool InlineRelocs) {
       raw_ostream &DebugOut = nulls();
 #endif
 
+      // Some targets (like WebAssembly) have a special prelude at the start
+      // of each symbol.
+      DisAsm->onSymbolStart(SymbolName, Size, Bytes.slice(Start, End - Start),
+                            SectionAddr + Start, DebugOut, CommentStream);
+      Start += Size;
+
       for (Index = Start; Index < End; Index += Size) {
         MCInst Inst;