code review 5622058: cmd/dist: generate files for package runtime

src/cmd/dist/buildruntime.c

+// Copyright 2012 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include "a.h"
+#include <stdio.h>
+
+/*
+ * Helpers for building pkg/runtime.
+ */
+
+// mkzversion writes zversion.go:
+//
+//      package runtime
+//      const defaultGoroot = <goroot>
+//      const theVersion = <version>
+//
+void
+mkzversion(char *dir, char *file)
+{
+        Buf b, out;
+········
+        binit(&b);
+        binit(&out);
+········
+        bwritestr(&out, bprintf(&b,
+                "// auto generated by go tool dist\n"
+                "\n"
+                "package runtime\n"
+                "\n"
+                "const defaultGoroot = `%s`\n"
+                "const theVersion = `%s`\n", goroot, goversion));
+
+        writefile(&out, file);
+········
+        bfree(&b);
+        bfree(&out);
+}
+
+// mkzgoarch writes zgoarch_$GOARCH.go:
+//
+//      package runtime
+//      const theGoarch = <goarch>
+//
+void
+mkzgoarch(char *dir, char *file)
+{
+        Buf b, out;
+········
+        binit(&b);
+        binit(&out);
+········
+        bwritestr(&out, bprintf(&b,
+                "// auto generated by go tool dist\n"
+                "\n"
+                "package runtime\n"
+                "\n"
+                "const theGoarch = `%s`\n", goarch));
+
+        writefile(&out, file);
+········
+        bfree(&b);
+        bfree(&out);
+}
+
+// mkzgoos writes zgoos_$GOOS.go:
+//
+//      package runtime
+//      const theGoos = <goos>
+//
+void
+mkzgoos(char *dir, char *file)
+{
+        Buf b, out;
+········
+        binit(&b);
+        binit(&out);
+········
+        bwritestr(&out, bprintf(&b,
+                "// auto generated by go tool dist\n"
+                "\n"
+                "package runtime\n"
+                "\n"
+                "const theGoos = `%s`\n", goos));
+
+        writefile(&out, file);
+········
+        bfree(&b);
+        bfree(&out);
+}
+
+static struct {
+        char *goarch;
+        char *goos;
+        char *hdr;
+} zasmhdr[] = {
+        {"386", "windows",
+                "#define        get_tls(r)      MOVL 0x14(FS), r\n"
+                "#define        g(r)    0(r)\n"
+                "#define        m(r)    4(r)\n"
+        },
+        {"386", "plan9",
+                "#define        get_tls(r)      MOVL _tos(SB), r \n"
+                "#define        g(r)    -8(r)\n"
+                "#define        m(r)    -4(r)\n"
+        },
+        {"386", "linux",
+                "// On Linux systems, what we call 0(GS) and 4(GS) for g and m\n"
+                "// turn into %gs:-8 and %gs:-4 (using gcc syntax to denote\n"
+                "// what the machine sees as opposed to 8l input).\n"
+                "// 8l rewrites 0(GS) and 4(GS) into these.\n"
+                "//\n"
+                "// On Linux Xen, it is not allowed to use %gs:-8 and %gs:-4\n"
+                "// directly.  Instead, we have to store %gs:0 into a temporary\n"
+                "// register and then use -8(%reg) and -4(%reg).  This kind\n"
+                "// of addressing is correct even when not running Xen.\n"
+                "//\n"
+                "// 8l can rewrite MOVL 0(GS), CX into the appropriate pair\n"
+                "// of mov instructions, using CX as the intermediate register\n"
+                "// (safe because CX is about to be written to anyway).\n"
+                "// But 8l cannot handle other instructions, like storing into 0(GS),\n"
+                "// which is where these macros come into play.\n"
+                "// get_tls sets up the temporary and then g and r use it.\n"
+                "//\n"
+                "// The final wrinkle is that get_tls needs to read from %gs:0,\n"
+                "// but in 8l input it's called 8(GS), because 8l is going to\n"
+                "// subtract 8 from all the offsets, as described above.\n"
+                "#define        get_tls(r)      MOVL 8(GS), r\n"
+                "#define        g(r)    -8(r)\n"
+                "#define        m(r)    -4(r)\n"
+        },
+        {"386", "",
+                "#define        get_tls(r)\n"
+                "#define        g(r)    0(GS)\n"
+                "#define        m(r)    4(GS)\n"
+        },
+········
+        {"amd64", "windows",
+                "#define        get_tls(r) MOVQ 0x28(GS), r\n"
+                "#define        g(r) 0(r)\n"
+                "#define        m(r) 8(r)\n"
+        },
+        {"amd64", "",
+                "// The offsets 0 and 8 are known to:\n"
+                "//     ../../cmd/6l/pass.c:/D_GS\n"
+                "//     cgo/gcc_linux_amd64.c:/^threadentry\n"
+                "//     cgo/gcc_darwin_amd64.c:/^threadentry\n"
+                "//\n"
+                "#define        get_tls(r)\n"
+                "#define        g(r) 0(GS)\n"
+                "#define        m(r) 8(GS)\n"
+        },
+········
+        {"arm", "",
+        "#define        g       R10\n"
+        "#define        m       R9\n"
+        "#define        LR      R14\n"
+        },
+};
+
+// mkzasm writes zasm_$GOOS_$GOARCH.h,
+// which contains struct offsets for use by
+// assembly files.  It also writes a copy to the work space
+// under the name zasm_GOOS_GOARCH.h (no expansion).
+//·
+void
+mkzasm(char *dir, char *file)
+{
+        int i, n;
+        char *aggr, *p;
+        Buf in, b, out;
+        Vec argv, lines, fields;
+
+        binit(&in);
+        binit(&b);
+        binit(&out);
+        vinit(&argv);
+        vinit(&lines);
+        vinit(&fields);
+········
+        bwritestr(&out, "// auto generated by go tool dist\n\n");
+        for(i=0; i<nelem(zasmhdr); i++) {
+                if(hasprefix(goarch, zasmhdr[i].goarch) && hasprefix(goos, zasmhdr[i].goos)) {
+                        bwritestr(&out, zasmhdr[i].hdr);
+                        goto ok;
+                }
+        }
+        fatal("unknown $GOOS/$GOARCH in mkzasm");
+ok:
+
+        // Run 6c -DGOOS_goos -DGOARCH_goarch -Iworkdir -a proc.c
+        // to get acid [sic] output.
+        vreset(&argv);
+        vadd(&argv, bpathf(&b, "%s/bin/tool/%sc", goroot, gochar));
+        vadd(&argv, bprintf(&b, "-DGOOS_%s", goos));
+        vadd(&argv, bprintf(&b, "-DGOARCH_%s", goarch));
+        vadd(&argv, bprintf(&b, "-I%s", workdir));
+        vadd(&argv, "-a");
+        vadd(&argv, "proc.c");
+        runv(&in, dir, CheckExit, &argv);
+········
+        // Convert input like
+        //      aggr G
+        //      {
+        //              Gobuf 24 sched;
+        //              'Y' 48 stack0;
+        //      }
+        // into output like
+        //      #define g_sched 24
+        //      #define g_stack0 48
+        //
+        aggr = nil;
+        splitlines(&lines, bstr(&in));
+        for(i=0; i<lines.len; i++) {
+                splitfields(&fields, lines.p[i]);
+                if(fields.len == 2 && streq(fields.p[0], "aggr")) {
+                        if(streq(fields.p[1], "G"))
+                                aggr = "g";
+                        else if(streq(fields.p[1], "M"))
+                                aggr = "m";
+                        else if(streq(fields.p[1], "Gobuf"))
+                                aggr = "gobuf";
+                        else if(streq(fields.p[1], "WinCall"))
+                                aggr = "wincall";
+                }
+                if(hasprefix(lines.p[i], "}"))
+                        aggr = nil;
+                if(aggr && hasprefix(lines.p[i], "\t") && fields.len >= 2) {
+                        n = fields.len;
+                        p = fields.p[n-1];
+                        if(p[xstrlen(p)-1] == ';')
+                                p[xstrlen(p)-1] = '\0';
+                        bwritestr(&out, bprintf(&b, "#define %s_%s %s\n", aggr, fields.p[n-1], fields.p[n-2]));
+                }
+        }
+········
+        // Write both to file and to workdir/zasm_GOOS_GOARCH.h.
+        writefile(&out, file);
+        writefile(&out, bprintf(&b, "%s/zasm_GOOS_GOARCH.h", workdir));
+
+        bfree(&in);
+        bfree(&b);
+        bfree(&out);
+        vfree(&argv);
+        vfree(&lines);
+        vfree(&fields);
+}
+
+static char *runtimedefs[] = {
+        "proc.c",
+        "iface.c",
+        "hashmap.c",
+        "chan.c",
+};
+
+// mkzruntimedefs writes zruntime_defs_$GOOS_$GOARCH.h,
+// which contains Go struct definitions equivalent to the C ones.
+// Mostly we just write the output of 6c -q to the file.
+// However, we run it on multiple files, so we have to delete
+// the duplicated definitions, and we don't care about the funcs
+// and consts, so we delete those too.
+//·
+void
+mkzruntimedefs(char *dir, char *file)
+{
+        int i, skip;
+        char *p;
+        Buf in, b, out;
+        Vec argv, lines, fields, seen;
+········
+        binit(&in);
+        binit(&b);
+        binit(&out);
+        vinit(&argv);
+        vinit(&lines);
+        vinit(&fields);
+        vinit(&seen);
+········
+        bwritestr(&out, "// auto generated by go tool dist\n"
+                "\n"
+                "package runtime\n"
+                "import \"unsafe\"\n"
+                "var _ unsafe.Pointer\n"
+                "\n"
+        );
+
+········
+        // Run 6c -DGOOS_goos -DGOARCH_goarch -Iworkdir -q
+        // on each of the runtimedefs C files.
+        vadd(&argv, bpathf(&b, "%s/bin/tool/%sc", goroot, gochar));
+        vadd(&argv, bprintf(&b, "-DGOOS_%s", goos));
+        vadd(&argv, bprintf(&b, "-DGOARCH_%s", goarch));
+        vadd(&argv, bprintf(&b, "-I%s", workdir));
+        vadd(&argv, "-q");
+        vadd(&argv, "");
+        p = argv.p[argv.len-1];
+        for(i=0; i<nelem(runtimedefs); i++) {
+                argv.p[argv.len-1] = runtimedefs[i];
+                runv(&b, dir, CheckExit, &argv);
+                bwriteb(&in, &b);
+        }
+        argv.p[argv.len-1] = p;
+················
+        // Process the aggregate output.
+        skip = 0;
+        splitlines(&lines, bstr(&in));
+        for(i=0; i<lines.len; i++) {
+                p = lines.p[i];
+                // Drop comment, func, and const lines.
+                if(hasprefix(p, "//") || hasprefix(p, "const") || hasprefix(p, "func"))
+                        continue;
+················
+                // Note beginning of type or var decl, which can be multiline.
+                // Remove duplicates.  The linear check of seen here makes the
+                // whole processing quadratic in aggregate, but there are only
+                // about 100 declarations, so this is okay (and simple).
+                if(hasprefix(p, "type ") || hasprefix(p, "var ")) {
+                        splitfields(&fields, p);
+                        if(fields.len < 2)
+                                continue;
+                        if(find(fields.p[1], seen.p, seen.len) >= 0) {
+                                if(streq(fields.p[fields.len-1], "{"))
+                                        skip = 1;  // skip until }
+                                continue;
+                        }
+                        vadd(&seen, fields.p[1]);
+                }
+                if(skip) {
+                        if(hasprefix(p, "}"))
+                                skip = 0;
+                        continue;
+                }
+················
+                bwritestr(&out, p);
+        }
+········
+        writefile(&out, file);
+
+        bfree(&in);
+        bfree(&b);
+        bfree(&out);
+        vfree(&argv);
+        vfree(&lines);
+        vfree(&fields);
+        vfree(&seen);
+}