Parse and lower llvm asm node

Parse and lower llvm asm node

Add a new HIR LlvmInlineAsm HIR node as well as some structures to
represent it's options and operands. Lower AST::LlvmInlineAsm node to it
and then create a tree from that node.

gcc/rust/ChangeLog:

	* ast/rust-ast-collector.cc (TokenCollector::visit): Remove unreachable
	code.
	* ast/rust-expr.h (struct LlvmOperand): Add LlvmOperand struct to
	represent input and outputs.
	(class LlvmInlineAsm): Add input, output and clobber operands.
	(struct TupleTemplateStr): Add locus getter.
	* backend/rust-compile-block.h: Add visit for LlvmInlineAsm.
	* backend/rust-compile-expr.cc (CompileExpr::visit): Add llvm inline
	asm stmt compilation.
	* backend/rust-compile-expr.h: Add function prototype.
	* backend/rust-compile-asm.h (class CompileLlvmAsm): Add llvm asm hir
	not to gimple.
	* backend/rust-compile-asm.cc (CompileLlvmAsm::CompileLlvmAsm): Add
	constructor.
	(CompileLlvmAsm::construct_operands): Add function to construct operand
	tree.
	(CompileLlvmAsm::construct_clobbers): Add function to construct clobber
	tree.
	(CompileLlvmAsm::tree_codegen_asm): Generate the whole tree for a given
	llvm inline assembly node.
	* checks/errors/borrowck/rust-bir-builder-expr-stmt.cc (ExprStmtBuilder::visit):
	Add visit function.
	* checks/errors/borrowck/rust-bir-builder-expr-stmt.h: Add function
	prototype.
	* checks/errors/borrowck/rust-bir-builder-lazyboolexpr.h: Add visit
	function.
	* checks/errors/borrowck/rust-bir-builder-struct.h: Likewise.
	* checks/errors/borrowck/rust-function-collector.h: Likewise.
	* checks/errors/privacy/rust-privacy-reporter.cc (PrivacyReporter::visit):
	Likewise.
	* checks/errors/privacy/rust-privacy-reporter.h: Add visit function
	prototype.
	* checks/errors/rust-const-checker.cc (ConstChecker::visit): Add visit
	function.
	* checks/errors/rust-const-checker.h: Add visit function prototype.
	* checks/errors/rust-hir-pattern-analysis.cc (PatternChecker::visit):
	Add visit function.
	* checks/errors/rust-hir-pattern-analysis.h: Add visit function
	prototype.
	* checks/errors/rust-unsafe-checker.cc (UnsafeChecker::visit): Add
	visit function.
	* checks/errors/rust-unsafe-checker.h: Add function prototype.
	* expand/rust-macro-builtins-asm.cc (parse_llvm_templates): Parse
	templates.
	(parse_llvm_arguments): Add function to parse non template tokens.
	(parse_llvm_operands): Add function to parse operands, either input or
	output.
	(parse_llvm_outputs): Add function to parse and collect llvm asm
	outputs.
	(parse_llvm_inputs): Likewise with inputs.
	(parse_llvm_clobbers): Add function to parse llvm asm clobbers.
	(parse_llvm_options): Add function to parse llvm asm options.
	(parse_llvm_asm): Add function to parse llvm asm.
	* expand/rust-macro-builtins-asm.h (class LlvmAsmContext): Add context
	for llvm asm parser.
	(parse_llvm_outputs): Add function prototype.
	(parse_llvm_inputs): Likewise.
	(parse_llvm_clobbers): Likewise.
	(parse_llvm_options): Likewise.
	* hir/rust-ast-lower-expr.cc (ASTLoweringExpr::visit): Lower AST llvm
	asm node to HIR.
	* hir/rust-ast-lower-expr.h: Add function prototype.
	* hir/rust-hir-dump.cc (Dump::visit): Add visit function.
	* hir/rust-hir-dump.h: Add function prototype.
	* hir/tree/rust-hir-expr-abstract.h: Add HIR llvm asm node kind.
	* hir/tree/rust-hir-expr.h (struct LlvmOperand): Add LlvmOperand type
	to represent input and outputs.
	(class LlvmInlineAsm): Add LlvmInlineAsm hir node.
	* hir/tree/rust-hir-full-decls.h (class LlvmInlineAsm): Add
	LlvmInlineAsm hir node forward declaration.
	* hir/tree/rust-hir-visitor.h: Add visit functions for LlvmInlineAsm
	hir node.
	* hir/tree/rust-hir.cc (LlvmInlineAsm::accept_vis): Add hir node
	visitor related functions.
	* typecheck/rust-hir-type-check-expr.cc (TypeCheckExpr::visit):
	Type check input and output operands.
	* typecheck/rust-hir-type-check-expr.h: Add function prototype.
	* ast/rust-ast-visitor.cc (DefaultASTVisitor::visit): Visit input and
	output operand expressions.
	* resolve/rust-ast-resolve-expr.cc (ResolveExpr::visit): Resolve input
	and output expressions.
	* resolve/rust-ast-resolve-expr.h: Add function prototypes.

Signed-off-by: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>