4 |
5 | [](https://github.com/decaf-lang/decaf/actions)
6 |
7 | Decaf is a Java-like, but much smaller programming language mainly for educational purpose.
8 | We now have at least three different implementations of the compiler in Java, Scala and Rust.
9 | Since the standard language has quite a limited set of language features, students are welcome to add their own new features.
10 |
11 | ## Getting Started
12 |
13 | This project requires
14 | * JDK 14
15 | * Gradle 6.5.1
16 |
17 | Other dependencies will be automatically downloaded from the maven central repository by the build script.
18 |
19 | After git clone, you need to setup submodules by
20 | ```
21 | git submodule update --recursive --init
22 | ```
23 |
24 | ## Build
25 |
26 | Type the standard Gradle build command in your CLI:
27 |
28 | ```sh
29 | gradle build
30 | ```
31 |
32 | The built jar will be located at `build/libs/decaf.jar`.
33 |
34 | Or, import the project in a Java IDE (like IDEA or Eclipse, or your favorite VS Code) and use gradle plugin, if available.
35 |
36 | ## Run
37 |
38 | In your CLI, type
39 |
40 | ```sh
41 | java -jar build/libs/decaf.jar -h
42 | ```
43 |
44 | to display the usage help.
45 |
46 | Possible targets/tasks are:
47 |
48 | - PA1: parse source code and output the pretty printed tree, or error messages
49 | - PA1-LL: like PA1, but use hand-coded LL parsing algorithm, with the help of a LL table generator [ll1pg](https://github.com/paulzfm/ll1pg)
50 | - PA2: type check and output the pretty printed scopes, or error messages
51 | - PA3: generate TAC (three-address code), dump it to a .tac file, and then output the execution result using our built-in simulator
52 | - PA4: currently same with PA3, will be reserved for students to do a bunch of optimizations on TAC
53 | - PA5: (default target) allocate registers and emit assembly code, currently we are using a very brute-force algorithm and only generates MIPS assembly code (with pseudo-ops, and no delayed branches)
54 |
55 | To run the MIPS assembly code, you may need [spim](http://spimsimulator.sourceforge.net), a MIPS32 simulator.
56 | For Mac OS users, simply install `spim` with `brew install spim` and run with `spim -file your_file.s`.
57 |
58 | ## Releases
59 |
60 | See https://github.com/decaf-lang/decaf/releases for releases, including separate frameworks for PA1 -- PA3.
61 |
62 | ## Materials
63 |
64 | We have a couple of Chinese documents on the language specification and implementation outlines:
65 |
66 | - https://decaf-lang.gitbook.io
67 | - https://decaf-project.gitbook.io
68 |
69 | ## Development & Contribution
70 |
71 | In future, we will develop on (possibly variates of) development branches,
72 | and only merge release versions into the master branch.
73 |
74 | Issues and pull requests for fixing bugs are welcome. However, adding new language features will not be considered, because that's students' work!
75 |
--------------------------------------------------------------------------------
/build.gradle:
--------------------------------------------------------------------------------
1 | plugins {
2 | id 'java'
3 | id 'org.xbib.gradle.plugin.jflex' version '1.2.0'
4 | id 'org.xbib.gradle.plugin.jacc' version '1.1.3'
5 | id 'de.undercouch.download' version "4.0.0"
6 | }
7 |
8 | group 'decaf'
9 |
10 | sourceCompatibility = JavaVersion.VERSION_14
11 |
12 | sourceSets.main.java.srcDirs += files("$project.buildDir/generated-src/ll1pg")
13 |
14 | repositories {
15 | mavenCentral()
16 | }
17 |
18 | dependencies {
19 | // https://mvnrepository.com/artifact/commons-cli/commons-cli
20 | implementation group: 'commons-cli', name: 'commons-cli', version: '1.4'
21 |
22 | // https://mvnrepository.com/artifact/commons-io/commons-io
23 | implementation group: 'commons-io', name: 'commons-io', version: '2.6'
24 |
25 | // https://mvnrepository.com/artifact/org.apache.commons/commons-lang3
26 | implementation group: 'org.apache.commons', name: 'commons-lang3', version: '3.9'
27 | }
28 |
29 | task ll1pg(type: Task) {
30 | download {
31 | src 'https://github.com/paulzfm/ll1pg/releases/download/decaf-course-19-fall/ll1pg-decaf-course-19-fall.jar'
32 | dest "$rootDir/ll1pg.jar"
33 | overwrite false
34 | }
35 |
36 | ConfigurableFileTree fs = fileTree(dir: file('src/main/ll1pg'), include: '**/*.spec')
37 | File dstDir = file("$project.buildDir/generated-src/ll1pg")
38 | delete(dstDir)
39 | mkdir(dstDir)
40 |
41 | if (fs.empty) System.err.println("No *.spec file found in 'src/main/ll1pg/', skip")
42 | fs.visit { FileVisitDetails f ->
43 | if (f.isDirectory()) return
44 | javaexec {
45 | classpath = files("$rootDir/ll1pg.jar")
46 | main = 'decaf.tools.ll1pg.Main'
47 | args = [f.file.path, dstDir.path]
48 | }
49 | }
50 | }
51 |
52 | tasks.compileJava.dependsOn tasks.ll1pg
53 |
54 | jar {
55 | manifest {
56 | attributes 'Main-Class': 'decaf.Main'
57 | }
58 |
59 | // Create a fat JAR with all the dependencies.
60 | from {
61 | configurations.runtimeClasspath.collect {
62 | it.isDirectory() ? it : zipTree(it)
63 | }
64 | }
65 | }
66 |
67 | javadoc {
68 | // Ignore the auto-generated file, because their javadoc comments may be out-dated (e.g. jflex ).
69 | source = sourceSets.main.allJava.filter { !it.toString().contains('generated-src') }
70 |
71 | options.source('14')
72 | // NOTE: the first '-' is added by Gradle and thus ignored.
73 | // See https://github.com/gradle/gradle/issues/2354
74 | options.showFromPrivate()
75 | }
76 |
77 |
--------------------------------------------------------------------------------
/gradle/wrapper/gradle-wrapper.jar:
--------------------------------------------------------------------------------
https://raw.githubusercontent.com/decaf-lang/decaf/3362432d12fc73af6c4200e1c5db3a36a578cbf5/gradle/wrapper/gradle-wrapper.jar
--------------------------------------------------------------------------------
/gradle/wrapper/gradle-wrapper.properties:
--------------------------------------------------------------------------------
1 | distributionBase=GRADLE_USER_HOME
2 | distributionPath=wrapper/dists
3 | distributionUrl=https\://services.gradle.org/distributions/gradle-6.5.1-bin.zip
4 | zipStoreBase=GRADLE_USER_HOME
5 | zipStorePath=wrapper/dists
6 |
--------------------------------------------------------------------------------
/gradlew:
--------------------------------------------------------------------------------
1 | #!/usr/bin/env sh
2 |
3 | #
4 | # Copyright 2015 the original author or authors.
5 | #
6 | # Licensed under the Apache License, Version 2.0 (the "License");
7 | # you may not use this file except in compliance with the License.
8 | # You may obtain a copy of the License at
9 | #
10 | # https://www.apache.org/licenses/LICENSE-2.0
11 | #
12 | # Unless required by applicable law or agreed to in writing, software
13 | # distributed under the License is distributed on an "AS IS" BASIS,
14 | # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 | # See the License for the specific language governing permissions and
16 | # limitations under the License.
17 | #
18 |
19 | ##############################################################################
20 | ##
21 | ## Gradle start up script for UN*X
22 | ##
23 | ##############################################################################
24 |
25 | # Attempt to set APP_HOME
26 | # Resolve links: $0 may be a link
27 | PRG="$0"
28 | # Need this for relative symlinks.
29 | while [ -h "$PRG" ] ; do
30 | ls=`ls -ld "$PRG"`
31 | link=`expr "$ls" : '.*-> \(.*\)$'`
32 | if expr "$link" : '/.*' > /dev/null; then
33 | PRG="$link"
34 | else
35 | PRG=`dirname "$PRG"`"/$link"
36 | fi
37 | done
38 | SAVED="`pwd`"
39 | cd "`dirname \"$PRG\"`/" >/dev/null
40 | APP_HOME="`pwd -P`"
41 | cd "$SAVED" >/dev/null
42 |
43 | APP_NAME="Gradle"
44 | APP_BASE_NAME=`basename "$0"`
45 |
46 | # Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
47 | DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
48 |
49 | # Use the maximum available, or set MAX_FD != -1 to use that value.
50 | MAX_FD="maximum"
51 |
52 | warn () {
53 | echo "$*"
54 | }
55 |
56 | die () {
57 | echo
58 | echo "$*"
59 | echo
60 | exit 1
61 | }
62 |
63 | # OS specific support (must be 'true' or 'false').
64 | cygwin=false
65 | msys=false
66 | darwin=false
67 | nonstop=false
68 | case "`uname`" in
69 | CYGWIN* )
70 | cygwin=true
71 | ;;
72 | Darwin* )
73 | darwin=true
74 | ;;
75 | MINGW* )
76 | msys=true
77 | ;;
78 | NONSTOP* )
79 | nonstop=true
80 | ;;
81 | esac
82 |
83 | CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
84 |
85 |
86 | # Determine the Java command to use to start the JVM.
87 | if [ -n "$JAVA_HOME" ] ; then
88 | if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
89 | # IBM's JDK on AIX uses strange locations for the executables
90 | JAVACMD="$JAVA_HOME/jre/sh/java"
91 | else
92 | JAVACMD="$JAVA_HOME/bin/java"
93 | fi
94 | if [ ! -x "$JAVACMD" ] ; then
95 | die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
96 |
97 | Please set the JAVA_HOME variable in your environment to match the
98 | location of your Java installation."
99 | fi
100 | else
101 | JAVACMD="java"
102 | which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
103 |
104 | Please set the JAVA_HOME variable in your environment to match the
105 | location of your Java installation."
106 | fi
107 |
108 | # Increase the maximum file descriptors if we can.
109 | if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
110 | MAX_FD_LIMIT=`ulimit -H -n`
111 | if [ $? -eq 0 ] ; then
112 | if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
113 | MAX_FD="$MAX_FD_LIMIT"
114 | fi
115 | ulimit -n $MAX_FD
116 | if [ $? -ne 0 ] ; then
117 | warn "Could not set maximum file descriptor limit: $MAX_FD"
118 | fi
119 | else
120 | warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
121 | fi
122 | fi
123 |
124 | # For Darwin, add options to specify how the application appears in the dock
125 | if $darwin; then
126 | GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
127 | fi
128 |
129 | # For Cygwin or MSYS, switch paths to Windows format before running java
130 | if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
131 | APP_HOME=`cygpath --path --mixed "$APP_HOME"`
132 | CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
133 |
134 | JAVACMD=`cygpath --unix "$JAVACMD"`
135 |
136 | # We build the pattern for arguments to be converted via cygpath
137 | ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
138 | SEP=""
139 | for dir in $ROOTDIRSRAW ; do
140 | ROOTDIRS="$ROOTDIRS$SEP$dir"
141 | SEP="|"
142 | done
143 | OURCYGPATTERN="(^($ROOTDIRS))"
144 | # Add a user-defined pattern to the cygpath arguments
145 | if [ "$GRADLE_CYGPATTERN" != "" ] ; then
146 | OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
147 | fi
148 | # Now convert the arguments - kludge to limit ourselves to /bin/sh
149 | i=0
150 | for arg in "$@" ; do
151 | CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
152 | CHECK2=`echo "$arg"|egrep -c "^-"` ### Determine if an option
153 |
154 | if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then ### Added a condition
155 | eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
156 | else
157 | eval `echo args$i`="\"$arg\""
158 | fi
159 | i=`expr $i + 1`
160 | done
161 | case $i in
162 | 0) set -- ;;
163 | 1) set -- "$args0" ;;
164 | 2) set -- "$args0" "$args1" ;;
165 | 3) set -- "$args0" "$args1" "$args2" ;;
166 | 4) set -- "$args0" "$args1" "$args2" "$args3" ;;
167 | 5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
168 | 6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
169 | 7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
170 | 8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
171 | 9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
172 | esac
173 | fi
174 |
175 | # Escape application args
176 | save () {
177 | for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
178 | echo " "
179 | }
180 | APP_ARGS=`save "$@"`
181 |
182 | # Collect all arguments for the java command, following the shell quoting and substitution rules
183 | eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
184 |
185 | exec "$JAVACMD" "$@"
186 |
--------------------------------------------------------------------------------
/gradlew.bat:
--------------------------------------------------------------------------------
1 | @rem
2 | @rem Copyright 2015 the original author or authors.
3 | @rem
4 | @rem Licensed under the Apache License, Version 2.0 (the "License");
5 | @rem you may not use this file except in compliance with the License.
6 | @rem You may obtain a copy of the License at
7 | @rem
8 | @rem https://www.apache.org/licenses/LICENSE-2.0
9 | @rem
10 | @rem Unless required by applicable law or agreed to in writing, software
11 | @rem distributed under the License is distributed on an "AS IS" BASIS,
12 | @rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 | @rem See the License for the specific language governing permissions and
14 | @rem limitations under the License.
15 | @rem
16 |
17 | @if "%DEBUG%" == "" @echo off
18 | @rem ##########################################################################
19 | @rem
20 | @rem Gradle startup script for Windows
21 | @rem
22 | @rem ##########################################################################
23 |
24 | @rem Set local scope for the variables with windows NT shell
25 | if "%OS%"=="Windows_NT" setlocal
26 |
27 | set DIRNAME=%~dp0
28 | if "%DIRNAME%" == "" set DIRNAME=.
29 | set APP_BASE_NAME=%~n0
30 | set APP_HOME=%DIRNAME%
31 |
32 | @rem Resolve any "." and ".." in APP_HOME to make it shorter.
33 | for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
34 |
35 | @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
36 | set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
37 |
38 | @rem Find java.exe
39 | if defined JAVA_HOME goto findJavaFromJavaHome
40 |
41 | set JAVA_EXE=java.exe
42 | %JAVA_EXE% -version >NUL 2>&1
43 | if "%ERRORLEVEL%" == "0" goto init
44 |
45 | echo.
46 | echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
47 | echo.
48 | echo Please set the JAVA_HOME variable in your environment to match the
49 | echo location of your Java installation.
50 |
51 | goto fail
52 |
53 | :findJavaFromJavaHome
54 | set JAVA_HOME=%JAVA_HOME:"=%
55 | set JAVA_EXE=%JAVA_HOME%/bin/java.exe
56 |
57 | if exist "%JAVA_EXE%" goto init
58 |
59 | echo.
60 | echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
61 | echo.
62 | echo Please set the JAVA_HOME variable in your environment to match the
63 | echo location of your Java installation.
64 |
65 | goto fail
66 |
67 | :init
68 | @rem Get command-line arguments, handling Windows variants
69 |
70 | if not "%OS%" == "Windows_NT" goto win9xME_args
71 |
72 | :win9xME_args
73 | @rem Slurp the command line arguments.
74 | set CMD_LINE_ARGS=
75 | set _SKIP=2
76 |
77 | :win9xME_args_slurp
78 | if "x%~1" == "x" goto execute
79 |
80 | set CMD_LINE_ARGS=%*
81 |
82 | :execute
83 | @rem Setup the command line
84 |
85 | set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
86 |
87 |
88 | @rem Execute Gradle
89 | "%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
90 |
91 | :end
92 | @rem End local scope for the variables with windows NT shell
93 | if "%ERRORLEVEL%"=="0" goto mainEnd
94 |
95 | :fail
96 | rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
97 | rem the _cmd.exe /c_ return code!
98 | if not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
99 | exit /b 1
100 |
101 | :mainEnd
102 | if "%OS%"=="Windows_NT" endlocal
103 |
104 | :omega
105 |
--------------------------------------------------------------------------------
/rt/runtime.c:
--------------------------------------------------------------------------------
1 | // These are various functions called by decaf programs.
2 | //
3 | // For MIPS their instructions are hardcoded, too bad.
4 | //
5 | // For x86-32 (i386), we implement the functions as a language runtime in C,
6 | // and everything work as below:
7 | //
8 | // +--------------------+ +------------------+
9 | // | Your Decaf Program | | language runtime |
10 | // +---------+----------+ +---------+--------+
11 | // | |
12 | // | The decaf compiler | gcc -m32 -S
13 | // | |
14 | // | |
15 | // v v
16 | // +--------------------+ +------------------+
17 | // | i386 assembly | | i386 assembly |
18 | // +---------------\----+ +---/--------------+
19 | // \ /
20 | // \ /
21 | // \ / gcc -m32
22 | // \ / (actually invoking the assembler `as`
23 | // \ / and the linker `ld`)
24 | // v v
25 | // +----------------------------+
26 | // | i386 executable code |
27 | // +-------------+--------------+
28 | // |
29 | // | run by your PC
30 | // |
31 | // v
32 |
33 | #include
48 | * Since no register allocation is done, the generated instructions may still contain pseudo registers (temps).
49 | *
50 | * @param func TAC function
51 | * @return a pair of the instruction sequence, and the basic info of the function
52 | */
53 | public abstract Pair
20 | * Recall the stack frame of a MIPS subroutine looks this:
21 | *
38 | * The parenthesized slots may not be used, but to make our life easier, we always reserve them.
39 | */
40 | public class MipsSubroutineEmitter extends SubroutineEmitter {
41 |
42 | MipsSubroutineEmitter(MipsAsmEmitter emitter, SubroutineInfo info) {
43 | super(emitter, info);
44 | nextLocalOffset = info.argsSize + 4 * Mips.calleeSaved.length + 4;
45 | printer.printLabel(info.funcLabel, "function " + info.funcLabel.prettyString());
46 | }
47 |
48 | @Override
49 | public void emitComment(String comment) {
50 | buf.add(NativeInstr.nativeComment(String.format("; %s", comment)));
51 | }
52 |
53 | @Override
54 | public void emitStoreToStack(Reg src) {
55 | if (!offsets.containsKey(src.temp)) {
56 | if (src.temp.index < info.numArg) { // Always map arg `i` to `SP + 4 * i`.
57 | offsets.put(src.temp, 4 * src.temp.index);
58 | } else {
59 | offsets.put(src.temp, nextLocalOffset);
60 | nextLocalOffset += 4;
61 | }
62 | }
63 |
64 | buf.add(new Mips.NativeStoreWord(src, Mips.SP, offsets.get(src.temp)));
65 | }
66 |
67 | @Override
68 | public void emitLoadFromStack(Reg dst, Temp src) {
69 | if (!offsets.containsKey(src)) {
70 | if (src.index < info.numArg) { // arg
71 | var offset = 4 * src.index;
72 | offsets.put(src, offset);
73 | buf.add(new Mips.NativeLoadWord(dst, Mips.SP, offset));
74 | return;
75 | }
76 |
77 | throw new IllegalArgumentException("offsets doesn't contain " + src + " when loading " + dst);
78 | }
79 |
80 | buf.add(new Mips.NativeLoadWord(dst, Mips.SP, offsets.get(src)));
81 | }
82 |
83 | @Override
84 | public void emitMove(Reg dst, Reg src) {
85 | buf.add(new Mips.NativeMove(dst, src));
86 | }
87 |
88 | @Override
89 | public void emitNative(NativeInstr instr) {
90 | buf.add(instr);
91 | }
92 |
93 | @Override
94 | public void emitLabel(Label label) {
95 | buf.add(new Mips.MipsLabel(label).toNative(new Reg[]{}, new Reg[]{}));
96 | }
97 |
98 | @Override
99 | public void emitEnd() {
100 | printer.printComment("start of prologue");
101 | printer.printInstr(new Mips.SPAdd(-nextLocalOffset), "push stack frame");
102 | if (Mips.RA.isUsed() || info.hasCalls) {
103 | printer.printInstr(new Mips.NativeStoreWord(Mips.RA, Mips.SP, info.argsSize + 4 * Mips.calleeSaved.length),
104 | "save the return address");
105 | }
106 | for (var i = 0; i < Mips.calleeSaved.length; i++) {
107 | if (Mips.calleeSaved[i].isUsed()) {
108 | printer.printInstr(new Mips.NativeStoreWord(Mips.calleeSaved[i], Mips.SP, info.argsSize + 4 * i),
109 | "save value of $S" + i);
110 | }
111 | }
112 | printer.printComment("end of prologue");
113 | printer.println();
114 |
115 | printer.printComment("start of body");
116 | for (var i = 0; i < Math.min(info.numArg, Mips.argRegs.length); i++) {
117 | printer.printInstr(new Mips.NativeStoreWord(Mips.argRegs[i], Mips.SP, 4 * i),
118 | "save arg " + i);
119 | }
120 | for (var i = Mips.argRegs.length; i < info.numArg; i++) {
121 | printer.printInstr(new Mips.NativeLoadWord(Mips.callerSaved[0], Mips.SP, nextLocalOffset + 4 * i),
122 | "load arg " + i);
123 | printer.printInstr(new Mips.NativeStoreWord(Mips.callerSaved[0], Mips.SP, 4 * i),
124 | "save arg " + i);
125 | }
126 | for (var instr : buf) {
127 | printer.printInstr(instr);
128 | }
129 | printer.printComment("end of body");
130 | printer.println();
131 |
132 | printer.printLabel(new Label(info.funcLabel.name + Mips.EPILOGUE_SUFFIX));
133 | printer.printComment("start of epilogue");
134 | for (var i = 0; i < Mips.calleeSaved.length; i++) {
135 | if (Mips.calleeSaved[i].isUsed()) {
136 | printer.printInstr(new Mips.NativeLoadWord(Mips.calleeSaved[i], Mips.SP, info.argsSize + 4 * i),
137 | "restore value of $S" + i);
138 | }
139 | }
140 | if (Mips.RA.isUsed() || info.hasCalls) {
141 | printer.printInstr(new Mips.NativeLoadWord(Mips.RA, Mips.SP, info.argsSize + 4 * Mips.calleeSaved.length),
142 | "restore the return address");
143 | }
144 | printer.printInstr(new Mips.SPAdd(nextLocalOffset), "pop stack frame");
145 | printer.printComment("end of epilogue");
146 | printer.println();
147 |
148 | printer.printInstr(new Mips.NativeReturn(), "return");
149 | printer.println();
150 | }
151 |
152 | private List
22 | * previous stack frame ...
23 | * SP + 4n + 40 + : local data m - 1
24 | * 4(m - 1)
25 | * ...
26 | * SP + 4n + 40 : local data 0
27 | * SP + 4n + 36 : ($RA)
28 | * SP + 4n + 32 : ($S8)
29 | * ...
30 | * SP + 4n + 0 : ($S0)
31 | * SP + 4(n - 1) : arg n - 1
32 | * ...
33 | * SP + 16 : arg 4
34 | * ...
35 | * SP : (arg 0)
36 | *
37 | *
18 | *
23 | */
24 | public enum Kind {
25 | CONTINUOUS, END_BY_JUMP, END_BY_COND_JUMP, END_BY_RETURN
26 | }
27 |
28 | public final Kind kind;
29 |
30 | /**
31 | * Block id.
32 | */
33 | public final int id;
34 |
35 | /**
36 | * Entry label of this block, if any.
37 | */
38 | public final Optional