PPC: [wasm] Fixes for embedded constant pools.

src/compiler/ppc/code-generator-ppc.cc

Index: src/compiler/ppc/code-generator-ppc.cc
diff --git a/src/compiler/ppc/code-generator-ppc.cc b/src/compiler/ppc/code-generator-ppc.cc
index 70b38c4d662c617003b70e89a890536c1dcd9f1f..5cfa2e6ff766bf0d2f7b55609f30a55754f238dc 100644
--- a/src/compiler/ppc/code-generator-ppc.cc
+++ b/src/compiler/ppc/code-generator-ppc.cc
@@ -1545,7 +1545,10 @@ void CodeGenerator::AssemblePrologue() {
   } else if (descriptor->IsJSFunctionCall()) {
     __ Prologue(this->info()->GeneratePreagedPrologue(), ip);
   } else if (frame()->needs_frame()) {
-    __ StubPrologue(ip);
+    // TODO(mbrandy): Detect the case where we're not generating an
+    // exported wasm function -- so that we can leverage ip to set up
+    // the constant pool pointer register.

[titzer, 2016/01/13 09:17:40]

To detect the compilation of a WASM function, you can get output_code_kind()
from the CompilationInfo, but I'm not sure that's the right check. I get crashes
on PPC for the WASM mjsunit tests (where the wrappers are compiled) in the
register allocator with and without this change. I dug a bit but I don't really
understand how IP is used in generated code.

+    __ StubPrologue();
   } else {
     frame()->SetElidedFrameSizeInSlots(0);
   }