*name* actually refers to the address for that space. Stack variables
work the same way, except that instead of being declared with global
variable definitions, they are declared with the `LLVM alloca
-instruction <../LangRef.html#i_alloca>`_:
+instruction <../LangRef.html#alloca-instruction>`_:
.. code-block:: llvm
funny pointer arithmetic is involved, the alloca will not be
promoted.
#. mem2reg only works on allocas of `first
- class <../LangRef.html#t_classifications>`_ values (such as pointers,
+ class <../LangRef.html#first-class-types>`_ values (such as pointers,
scalars and vectors), and only if the array size of the allocation is
1 (or missing in the .ll file). mem2reg is not capable of promoting
structs or arrays to registers. Note that the "scalarrepl" pass is
.. code-block:: c++
- Value *VariableExprAST::Codegen() {
+ Value *VariableExprAST::codegen() {
// Look this variable up in the function.
Value *V = NamedValues[Name];
- if (V == 0) return ErrorV("Unknown variable name");
+ if (!V)
+ return ErrorV("Unknown variable name");
// Load the value.
return Builder.CreateLoad(V, Name.c_str());
As you can see, this is pretty straightforward. Now we need to update
the things that define the variables to set up the alloca. We'll start
-with ``ForExprAST::Codegen`` (see the `full code listing <#code>`_ for
+with ``ForExprAST::codegen()`` (see the `full code listing <#id1>`_ for
the unabridged code):
.. code-block:: c++
AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
// Emit the start code first, without 'variable' in scope.
- Value *StartVal = Start->Codegen();
- if (StartVal == 0) return 0;
+ Value *StartVal = Start->codegen();
+ if (!StartVal)
+ return nullptr;
// Store the value into the alloca.
Builder.CreateStore(StartVal, Alloca);
...
// Compute the end condition.
- Value *EndCond = End->Codegen();
- if (EndCond == 0) return EndCond;
+ Value *EndCond = End->codegen();
+ if (!EndCond)
+ return nullptr;
// Reload, increment, and restore the alloca. This handles the case where
// the body of the loop mutates the variable.
...
This code is virtually identical to the code `before we allowed mutable
-variables <LangImpl5.html#forcodegen>`_. The big difference is that we
+variables <LangImpl5.html#code-generation-for-the-for-loop>`_. The big difference is that we
no longer have to construct a PHI node, and we use load/store to access
the variable as needed.
For each argument, we make an alloca, store the input value to the
function into the alloca, and register the alloca as the memory location
-for the argument. This method gets invoked by ``FunctionAST::Codegen``
+for the argument. This method gets invoked by ``FunctionAST::codegen()``
right after it sets up the entry block for the function.
The final missing piece is adding the mem2reg pass, which allows us to
.. code-block:: c++
- Value *BinaryExprAST::Codegen() {
+ Value *BinaryExprAST::codegen() {
// Special case '=' because we don't want to emit the LHS as an expression.
if (Op == '=') {
// Assignment requires the LHS to be an identifier.
.. code-block:: c++
// Codegen the RHS.
- Value *Val = RHS->Codegen();
- if (Val == 0) return 0;
+ Value *Val = RHS->codegen();
+ if (!Val)
+ return nullptr;
// Look up the name.
Value *Variable = NamedValues[LHSE->getName()];
- if (Variable == 0) return ErrorV("Unknown variable name");
+ if (!Variable)
+ return ErrorV("Unknown variable name");
Builder.CreateStore(Val, Variable);
return Val;
...
static int gettok() {
...
- if (IdentifierStr == "in") return tok_in;
- if (IdentifierStr == "binary") return tok_binary;
- if (IdentifierStr == "unary") return tok_unary;
- if (IdentifierStr == "var") return tok_var;
+ if (IdentifierStr == "in")
+ return tok_in;
+ if (IdentifierStr == "binary")
+ return tok_binary;
+ if (IdentifierStr == "unary")
+ return tok_unary;
+ if (IdentifierStr == "var")
+ return tok_var;
return tok_identifier;
...
class VarExprAST : public ExprAST {
std::vector<std::pair<std::string, std::unique_ptr<ExprAST>>> VarNames;
std::unique_ptr<ExprAST> Body;
+
public:
VarExprAST(std::vector<std::pair<std::string, std::unique_ptr<ExprAST>>> VarNames,
std::unique_ptr<ExprAST> body)
: VarNames(std::move(VarNames)), Body(std::move(Body)) {}
- virtual Value *Codegen();
+ virtual Value *codegen();
};
var/in allows a list of names to be defined all at once, and each name
/// ::= varexpr
static std::unique_ptr<ExprAST> ParsePrimary() {
switch (CurTok) {
- default: return Error("unknown token when expecting an expression");
- case tok_identifier: return ParseIdentifierExpr();
- case tok_number: return ParseNumberExpr();
- case '(': return ParseParenExpr();
- case tok_if: return ParseIfExpr();
- case tok_for: return ParseForExpr();
- case tok_var: return ParseVarExpr();
+ default:
+ return Error("unknown token when expecting an expression");
+ case tok_identifier:
+ return ParseIdentifierExpr();
+ case tok_number:
+ return ParseNumberExpr();
+ case '(':
+ return ParseParenExpr();
+ case tok_if:
+ return ParseIfExpr();
+ case tok_for:
+ return ParseForExpr();
+ case tok_var:
+ return ParseVarExpr();
}
}
getNextToken(); // eat 'in'.
auto Body = ParseExpression();
- if (!Body) return nullptr;
+ if (!Body)
+ return nullptr;
return llvm::make_unique<VarExprAST>(std::move(VarNames),
std::move(Body));
.. code-block:: c++
- Value *VarExprAST::Codegen() {
+ Value *VarExprAST::codegen() {
std::vector<AllocaInst *> OldBindings;
Function *TheFunction = Builder.GetInsertBlock()->getParent();
// var a = a in ... # refers to outer 'a'.
Value *InitVal;
if (Init) {
- InitVal = Init->Codegen();
- if (InitVal == 0) return 0;
+ InitVal = Init->codegen();
+ if (!InitVal)
+ return nullptr;
} else { // If not specified, use 0.0.
InitVal = ConstantFP::get(getGlobalContext(), APFloat(0.0));
}
.. code-block:: c++
// Codegen the body, now that all vars are in scope.
- Value *BodyVal = Body->Codegen();
- if (BodyVal == 0) return 0;
+ Value *BodyVal = Body->codegen();
+ if (!BodyVal)
+ return nullptr;
Finally, before returning, we restore the previous variable bindings:
projects / oota-llvm.git / blobdiff