auto merge of #15005 : dotdash/rust/i1_bool, r=alexcrichton

We currently compiled bools to i8 values, because there was a bug in
LLVM that sometimes caused miscompilations when using i1 in, for
example, structs.

Using i8 means a lot of unnecessary zero-extend and truncate operations
though, since we have to convert the value from and to i1 when using for
example icmp or br instructions. Besides the unnecessary overhead caused
by this, it also sometimes made LLVM miss some optimizations.

First, we have to fix some bugs concerning the handling of
attributes in foreign function declarations and calls. These
are required because the i1 type needs the ZExt attribute when
used as a function parameter or return type.

Then we have to update LLVM to get a bugfix without which LLVM
sometimes generates broken code when using i1.

And then, finally, we can switch bools over to i1.

1 files changed, 10 insertions, 2 deletions

diff --git a/src/rustllvm/RustWrapper.cpp b/src/rustllvm/RustWrapper.cpp
index f42844b9f19..a1a88d1b14d 100644
--- a/src/rustllvm/RustWrapper.cpp
+++ b/src/rustllvm/RustWrapper.cpp
@@ -659,7 +659,7 @@ LLVMRustLinkInExternalBitcode(LLVMModuleRef dst, char *bc, size_t len) {
 extern "C" void*
 LLVMRustOpenArchive(char *path) {
     std::unique_ptr<MemoryBuffer> buf;
-    error_code err = MemoryBuffer::getFile(path, buf);
+    std::error_code err = MemoryBuffer::getFile(path, buf);
     if (err) {
         LLVMRustSetLastError(err.message().c_str());
         return NULL;
@@ -694,14 +694,18 @@ LLVMRustArchiveReadSection(Archive *ar, char *name, size_t *size) {
 #if LLVM_VERSION_MINOR >= 5
     Archive::child_iterator child = ar->child_begin(),
                               end = ar->child_end();
+    for (; child != end; ++child) {
+        ErrorOr<StringRef> name_or_err = child->getName();
+        if (name_or_err.getError()) continue;
+        StringRef sect_name = name_or_err.get();
 #else
     Archive::child_iterator child = ar->begin_children(),
                               end = ar->end_children();
-#endif
     for (; child != end; ++child) {
         StringRef sect_name;
         error_code err = child->getName(sect_name);
         if (err) continue;
+#endif
         if (sect_name.trim(" ") == name) {
             StringRef buf = child->getBuffer();
             *size = buf.size();
@@ -757,7 +761,11 @@ inline section_iterator *unwrap(LLVMSectionIteratorRef SI) {
 extern "C" int
 LLVMRustGetSectionName(LLVMSectionIteratorRef SI, const char **ptr) {
     StringRef ret;
+#if LLVM_VERSION_MINOR >= 5
+    if (std::error_code ec = (*unwrap(SI))->getName(ret))
+#else
     if (error_code ec = (*unwrap(SI))->getName(ret))
+#endif
       report_fatal_error(ec.message());
     *ptr = ret.data();
     return ret.size();