commit 685c5e838a59c6c84883bd9b4250da01a9dcabe4
author Sam Clegg <sbc@chromium.org> Wed Apr 04 22:27:58 2018 +0000
committer Sam Clegg <sbc@chromium.org> Wed Apr 04 22:27:58 2018 +0000
tree 1cd5ec5b6b451e897f568b5b13138f85cb1229af
parent 0f87a807950704b080dab6ec3cf06ff77eaf3cb0

[WebAssembly] Only write 32-bits for WebAssembly::OPERAND_OFFSET32

A bug was found where an offset of -1 would generate an encoding
of max int64 which is invalid in the binary format.

Differential Revision: https://reviews.llvm.org/D45280

llvm-svn: 329238

llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCCodeEmitter.cpp

diff --git a/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCCodeEmitter.cpp b/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCCodeEmitter.cpp
index 2baa135..440b9a5 100644
--- a/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCCodeEmitter.cpp
+++ b/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCCodeEmitter.cpp
@@ -23,9 +23,11 @@
 #include "llvm/MC/MCRegisterInfo.h"
 #include "llvm/MC/MCSubtargetInfo.h"
 #include "llvm/MC/MCSymbol.h"
+#include "llvm/Support/Debug.h"
 #include "llvm/Support/EndianStream.h"
 #include "llvm/Support/LEB128.h"
 #include "llvm/Support/raw_ostream.h"
+
 using namespace llvm;
 
 #define DEBUG_TYPE "mccodeemitter"
@@ -86,8 +88,11 @@
         assert(Desc.TSFlags == 0 &&
                "WebAssembly non-variable_ops don't use TSFlags");
         const MCOperandInfo &Info = Desc.OpInfo[i];
+        DEBUG(dbgs() << "Encoding immediate: type=" << int(Info.OperandType) << "\n");
         if (Info.OperandType == WebAssembly::OPERAND_I32IMM) {
           encodeSLEB128(int32_t(MO.getImm()), OS);
+        } else if (Info.OperandType == WebAssembly::OPERAND_OFFSET32) {
+          encodeULEB128(uint32_t(MO.getImm()), OS);
         } else if (Info.OperandType == WebAssembly::OPERAND_I64IMM) {
           encodeSLEB128(int64_t(MO.getImm()), OS);
         } else if (Info.OperandType == WebAssembly::OPERAND_GLOBAL) {