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Add checks about references to non-lvalues.

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Both ReturnStmt and DeclStmt now check the values being associated
with references to make sure that they are legal (e.g. it's illegal
to assign a varying lvalue, or a compile-time constant to a reference
type).  Previously we didn't catch this and would end up hitting
assertions in LLVM when code did this stuff.

Mostly fixes issue #225 (except for adding a FAQ about what this
error message means.)
This commit is contained in:
Matt Pharr
2012-04-04 05:56:22 -07:00
parent 637d076e99
commit c27418da77
9 changed files with 83 additions and 14 deletions
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57
stmt.cpp
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@@ -1,5 +1,5 @@
/*
Copyright (c) 2010-2011, Intel Corporation
Copyright (c) 2010-2012, Intel Corporation
All rights reserved.
Redistribution and use in source and binary forms, with or without
@@ -40,6 +40,7 @@
#include "util.h"
#include "expr.h"
#include "type.h"
#include "func.h"
#include "sym.h"
#include "module.h"
#include "llvmutil.h"
@@ -167,11 +168,25 @@ DeclStmt::EmitCode(FunctionEmitContext *ctx) const {
}
// References must have initializer expressions as well.
if (dynamic_cast<const ReferenceType *>(sym->type) && initExpr == NULL) {
Error(sym->pos,
"Must provide initializer for reference-type variable \"%s\".",
sym->name.c_str());
continue;
if (IsReferenceType(sym->type) == true) {
if (initExpr == NULL) {
Error(sym->pos, "Must provide initializer for reference-type "
"variable \"%s\".", sym->name.c_str());
continue;
}
if (IsReferenceType(initExpr->GetType()) == false) {
const Type *initLVType = initExpr->GetLValueType();
if (initLVType == NULL) {
Error(initExpr->pos, "Initializer for reference-type variable "
"\"%s\" must have an lvalue type.", sym->name.c_str());
continue;
}
if (initLVType->IsUniformType() == false) {
Error(initExpr->pos, "Initializer for reference-type variable "
"\"%s\" must have a uniform lvalue type.", sym->name.c_str());
continue;
}
}
}
LLVM_TYPE_CONST llvm::Type *llvmType = sym->type->LLVMType(g->ctx);
@@ -2173,8 +2188,8 @@ SwitchStmt::EstimateCost() const {
///////////////////////////////////////////////////////////////////////////
// ReturnStmt
ReturnStmt::ReturnStmt(Expr *v, bool cc, SourcePos p)
: Stmt(p), val(v),
ReturnStmt::ReturnStmt(Expr *e, bool cc, SourcePos p)
: Stmt(p), expr(e),
doCoherenceCheck(cc && !g->opt.disableCoherentControlFlow) {
}
@@ -2189,8 +2204,29 @@ ReturnStmt::EmitCode(FunctionEmitContext *ctx) const {
return;
}
// Make sure we're not trying to return a reference to something where
// that doesn't make sense
const Function *func = ctx->GetFunction();
const Type *returnType = func->GetReturnType();
if (IsReferenceType(returnType) == true &&
IsReferenceType(expr->GetType()) == false) {
const Type *lvType = expr->GetLValueType();
if (lvType == NULL) {
Error(expr->pos, "Illegal to return non-lvalue from function "
"returning reference type \"%s\".",
returnType->GetString().c_str());
return;
}
else if (lvType->IsUniformType() == false) {
Error(expr->pos, "Illegal to return varying lvalue type from "
"function returning a reference type \"%s\".",
returnType->GetString().c_str());
return;
}
}
ctx->SetDebugPos(pos);
ctx->CurrentLanesReturned(val, doCoherenceCheck);
ctx->CurrentLanesReturned(expr, doCoherenceCheck);
}
@@ -2210,7 +2246,8 @@ void
ReturnStmt::Print(int indent) const {
printf("%*c%sReturn Stmt", indent, ' ', doCoherenceCheck ? "Coherent " : "");
pos.Print();
if (val) val->Print();
if (expr)
expr->Print();
else printf("(void)");
printf("\n");
}