source: src/Common/Eval.cc@ 7db39f7

Last change on this file since 7db39f7 was c6b4432, checked in by Andrew Beach <ajbeach@…>, 2 years ago

Remove BaseSyntaxNode and clean-up.
  • Property mode set to 100644
File size: 7.2 KB
Line 
1//
2// Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo
3//
4// The contents of this file are covered under the licence agreement in the
5// file "LICENCE" distributed with Cforall.
6//
7// Eval.cc -- Evaluate parts of the ast at compile time.
8//
9// Author : Richard C. Bilson
10// Created On : Mon May 18 07:44:20 2015
11// Last Modified By : Peter A. Buhr
12// Last Modified On : Sat Aug 6 12:11:59 2022
13// Update Count : 119
14//
15
16#include "Eval.h"
17
18#include <utility> // for pair
19
20#include "AST/Inspect.hpp"
21#include "CodeGen/OperatorTable.h" // access: OperatorInfo
22#include "AST/Pass.hpp"
23#include "InitTweak/InitTweak.h"
24
25struct EvalNew : public ast::WithShortCircuiting {
26 Evaluation result = { 0, true, true };
27
28 void previsit( const ast::Node * ) { visit_children = false; }
29 void postvisit( const ast::Node * ) { result.isEvaluableInGCC = result.hasKnownValue = false; }
30
31 void postvisit( const ast::UntypedExpr * ) {
32 assertf( false, "UntypedExpr in constant expression evaluation" ); // FIX ME, resolve variable
33 }
34
35 void postvisit( const ast::ConstantExpr * expr ) { // only handle int constants
36 result.knownValue = expr->intValue();
37 result.hasKnownValue = true;
38 result.isEvaluableInGCC = true;
39 }
40
41 void postvisit( const ast::SizeofExpr * ) {
42 result.hasKnownValue = false;
43 result.isEvaluableInGCC = true;
44 }
45
46 void postvisit( const ast::AlignofExpr * ) {
47 result.hasKnownValue = false;
48 result.isEvaluableInGCC = true;
49 }
50
51 void postvisit( const ast::OffsetofExpr * ) {
52 result.hasKnownValue = false;
53 result.isEvaluableInGCC = true;
54 }
55
56 void postvisit( const ast::LogicalExpr * expr ) {
57 Evaluation arg1, arg2;
58 arg1 = eval( expr->arg1 );
59 result.isEvaluableInGCC &= arg1.isEvaluableInGCC;
60 if ( ! result.isEvaluableInGCC ) return;
61 arg2 = eval( expr->arg2 );
62 result.isEvaluableInGCC &= arg2.isEvaluableInGCC;
63 if ( ! result.isEvaluableInGCC ) return;
64
65 result.hasKnownValue &= arg1.hasKnownValue;
66 result.hasKnownValue &= arg2.hasKnownValue;
67 if ( ! result.hasKnownValue ) return;
68
69 if ( expr->isAnd ) {
70 result.knownValue = arg1.knownValue && arg2.knownValue;
71 } else {
72 result.knownValue = arg1.knownValue || arg2.knownValue;
73 } // if
74 }
75
76 void postvisit( const ast::ConditionalExpr * expr ) {
77 Evaluation arg1, arg2, arg3;
78 arg1 = eval( expr->arg1 );
79 result.isEvaluableInGCC &= arg1.isEvaluableInGCC;
80 if ( ! result.isEvaluableInGCC ) return;
81 arg2 = eval( expr->arg2 );
82 result.isEvaluableInGCC &= arg2.isEvaluableInGCC;
83 if ( ! result.isEvaluableInGCC ) return;
84 arg3 = eval( expr->arg3 );
85 result.isEvaluableInGCC &= arg3.isEvaluableInGCC;
86 if ( ! result.isEvaluableInGCC ) return;
87
88 result.hasKnownValue &= arg1.hasKnownValue;
89 result.hasKnownValue &= arg2.hasKnownValue;
90 result.hasKnownValue &= arg3.hasKnownValue;
91 if ( ! result.hasKnownValue ) return;
92
93 result.knownValue = arg1.knownValue ? arg2.knownValue : arg3.knownValue;
94 }
95
96 void postvisit( const ast::CastExpr * expr ) {
97 // cfa-cc generates a cast before every constant and many other places, e.g., (int)3,
98 // so we must use the value from the cast argument, even though we lack any basis for evaluating wraparound effects, etc
99 result = eval(expr->arg);
100 }
101
102 void postvisit( const ast::VariableExpr * expr ) {
103 result.hasKnownValue = false;
104 result.isEvaluableInGCC = false;
105 if ( const ast::EnumInstType * inst = dynamic_cast<const ast::EnumInstType *>(expr->result.get()) ) {
106 if ( const ast::EnumDecl * decl = inst->base ) {
107 result.isEvaluableInGCC = true;
108 result.hasKnownValue = decl->valueOf( expr->var, result.knownValue ); // result.knownValue filled by valueOf
109 }
110 }
111 }
112
113 void postvisit( const ast::ApplicationExpr * expr ) {
114 const ast::DeclWithType * function = ast::getFunction(expr);
115 if ( ! function || function->linkage != ast::Linkage::Intrinsic ) {
116 result.isEvaluableInGCC = false;
117 result.hasKnownValue = false;
118 return;
119 }
120 const std::string & fname = function->name;
121 assertf( expr->args.size() == 1 || expr->args.size() == 2, "Intrinsic function with %zd arguments: %s", expr->args.size(), fname.c_str() );
122
123 if ( expr->args.size() == 1 ) {
124 // pre/postfix operators ++ and -- => assignment, which is not constant
125 Evaluation arg1;
126 arg1 = eval(expr->args.front());
127 result.isEvaluableInGCC &= arg1.isEvaluableInGCC;
128 if ( ! result.isEvaluableInGCC ) return;
129
130 result.hasKnownValue &= arg1.hasKnownValue;
131 if ( ! result.hasKnownValue ) return;
132
133 if (fname == "+?") {
134 result.knownValue = arg1.knownValue;
135 } else if (fname == "-?") {
136 result.knownValue = -arg1.knownValue;
137 } else if (fname == "~?") {
138 result.knownValue = ~arg1.knownValue;
139 } else if (fname == "!?") {
140 result.knownValue = ! arg1.knownValue;
141 } else {
142 result.isEvaluableInGCC = false;
143 result.hasKnownValue = false;
144 } // if
145 } else { // => expr->args.size() == 2
146 // infix assignment operators => assignment, which is not constant
147 Evaluation arg1, arg2;
148 arg1 = eval(expr->args.front());
149 result.isEvaluableInGCC &= arg1.isEvaluableInGCC;
150 if ( ! result.isEvaluableInGCC ) return;
151 arg2 = eval(expr->args.back());
152 result.isEvaluableInGCC &= arg2.isEvaluableInGCC;
153 if ( ! result.isEvaluableInGCC ) return;
154
155 result.hasKnownValue &= arg1.hasKnownValue;
156 result.hasKnownValue &= arg2.hasKnownValue;
157 if ( ! result.hasKnownValue ) return;
158
159 if (fname == "?+?") {
160 result.knownValue = arg1.knownValue + arg2.knownValue;
161 } else if (fname == "?-?") {
162 result.knownValue = arg1.knownValue - arg2.knownValue;
163 } else if (fname == "?*?") {
164 result.knownValue = arg1.knownValue * arg2.knownValue;
165 } else if (fname == "?/?") {
166 if ( arg2.knownValue ) result.knownValue = arg1.knownValue / arg2.knownValue;
167 } else if (fname == "?%?") {
168 if ( arg2.knownValue ) result.knownValue = arg1.knownValue % arg2.knownValue;
169 } else if (fname == "?<<?") {
170 result.knownValue = arg1.knownValue << arg2.knownValue;
171 } else if (fname == "?>>?") {
172 result.knownValue = arg1.knownValue >> arg2.knownValue;
173 } else if (fname == "?<?") {
174 result.knownValue = arg1.knownValue < arg2.knownValue;
175 } else if (fname == "?>?") {
176 result.knownValue = arg1.knownValue > arg2.knownValue;
177 } else if (fname == "?<=?") {
178 result.knownValue = arg1.knownValue <= arg2.knownValue;
179 } else if (fname == "?>=?") {
180 result.knownValue = arg1.knownValue >= arg2.knownValue;
181 } else if (fname == "?==?") {
182 result.knownValue = arg1.knownValue == arg2.knownValue;
183 } else if (fname == "?!=?") {
184 result.knownValue = arg1.knownValue != arg2.knownValue;
185 } else if (fname == "?&?") {
186 result.knownValue = arg1.knownValue & arg2.knownValue;
187 } else if (fname == "?^?") {
188 result.knownValue = arg1.knownValue ^ arg2.knownValue;
189 } else if (fname == "?|?") {
190 result.knownValue = arg1.knownValue | arg2.knownValue;
191 } else {
192 result.isEvaluableInGCC = false;
193 result.hasKnownValue = false;
194 }
195 } // if
196 // TODO: implement other intrinsic functions
197 }
198};
199
200Evaluation eval( const ast::Expr * expr ) {
201 if ( expr ) {
202
203 return ast::Pass<EvalNew>::read(expr);
204 // Evaluation ret = ast::Pass<EvalNew>::read(expr);
205 // ret.knownValue = 777;
206 // return ret;
207
208 } else {
209 return { 0, false, false };
210 }
211}
212
213// Local Variables: //
214// tab-width: 4 //
215// mode: c++ //
216// compile-command: "make install" //
217// End: //
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