build: implement GOEXPERIMENT again in runtime, and add to liblink

For Austin's framepointer experiment.

Change-Id: I81b6f414943b3578924f853300b9193684f79bf4
Reviewed-on: https://go-review.googlesource.com/2994
Reviewed-by: Austin Clements <austin@google.com>

diff --git a/include/link.h b/include/link.h
index 15a28787928d68a16ea04b0cc92b6c4c24e35620..6c8db0e7d727d76c927b7dd1a8c6def80ac94b52 100644 (file)
--- a/include/link.h
+++ b/include/link.h
@@ -586,6 +586,11 @@ void*      emallocz(long n);
 void*  erealloc(void *p, long n);
 char*  estrdup(char *p);
 char*  expandpkg(char *t0, char *pkg);
+void   linksetexp(void);
+char*  expstring(void);
+
+extern int     fieldtrack_enabled;
+extern int     framepointer_enabled;
 
 // ld.c
 void   addhist(Link *ctxt, int32 line, int type);
@@ -656,6 +661,9 @@ extern      LinkArch        linkarm;
 extern LinkArch        linkppc64;
 extern LinkArch        linkppc64le;
 
+extern int     linkbasepointer;
+extern void    linksetexp(void);
+
 #pragma        varargck        type    "A"     int
 #pragma        varargck        type    "E"     uint
 #pragma        varargck        type    "D"     Addr*

diff --git a/src/cmd/dist/build.go b/src/cmd/dist/build.go
index 9e4d1e3c22aef85b803a5baeb0deb6451369ebaa..82c2273b234a715305de812da3c6d587e9cbf57d 100644 (file)
--- a/src/cmd/dist/build.go
+++ b/src/cmd/dist/build.go
@@ -576,7 +576,6 @@ var deptab = []struct {
                "$GOROOT/pkg/obj/${GOHOSTOS}_$GOHOSTARCH/lib9.a",
        }},
        {"runtime", []string{
-               "zaexperiment.h",
                "zversion.go",
        }},
 }
@@ -601,7 +600,6 @@ var gentab = []struct {
        {"anames9.c", mkanames},
        {"zdefaultcc.go", mkzdefaultcc},
        {"zversion.go", mkzversion},
-       {"zaexperiment.h", mkzexperiment},
 
        // not generated anymore, but delete the file if we see it
        {"enam.c", nil},
@@ -937,8 +935,8 @@ func install(dir string) {
                                )
                        }
 
-                       // gc/lex.c records the GOEXPERIMENT setting used during the build.
-                       if name == "lex.c" {
+                       // liblink/go.c records the GOEXPERIMENT setting used during the build.
+                       if name == "go.c" {
                                compile = append(compile,
                                        "-D", fmt.Sprintf("GOEXPERIMENT=%q", os.Getenv("GOEXPERIMENT")))
                        }

diff --git a/src/cmd/dist/buildruntime.go b/src/cmd/dist/buildruntime.go
index 1e6ae823972b564c5989fb7fc4690ec0684bce15..d659234578ff0be6009b3c8e34b8be89f092215e 100644 (file)
--- a/src/cmd/dist/buildruntime.go
+++ b/src/cmd/dist/buildruntime.go
@@ -27,21 +27,8 @@ func mkzversion(dir, file string) {
                        "\n"+
                        "const defaultGoroot = `%s`\n"+
                        "const theVersion = `%s`\n"+
-                       "\n"+
-                       "var buildVersion = theVersion\n", goroot_final, goversion)
-
-       writefile(out, file, 0)
-}
-
-// mkzexperiment writes zaexperiment.h (sic):
-//
-//     #define GOEXPERIMENT "experiment string"
-//
-func mkzexperiment(dir, file string) {
-       out := fmt.Sprintf(
-               "// auto generated by go tool dist\n"+
-                       "\n"+
-                       "#define GOEXPERIMENT \"%s\"\n", os.Getenv("GOEXPERIMENT"))
+                       "const goexperiment = `%s`\n"+
+                       "var buildVersion = theVersion\n", goroot_final, goversion, os.Getenv("GOEXPERIMENT"))
 
        writefile(out, file, 0)
 }

diff --git a/src/cmd/gc/go.h b/src/cmd/gc/go.h
index 21cf8b894d1daae400a94629f424ab03aa5af182..5a2b774316c227d104cb8cac5431bf26b59d2a54 100644 (file)
--- a/src/cmd/gc/go.h
+++ b/src/cmd/gc/go.h
@@ -994,8 +994,6 @@ EXTERN      int     debuglive;
 EXTERN Link*   ctxt;
 
 EXTERN int     nointerface;
-EXTERN int     fieldtrack_enabled;
-EXTERN int     precisestack_enabled;
 EXTERN int     writearchive;
 
 EXTERN Biobuf  bstdout;

diff --git a/src/cmd/gc/lex.c b/src/cmd/gc/lex.c
index 006ded20e872937cfa87bdce35c11f259772adea..29fb2e1603ac11f5d49b79773801bc8f4525aa66 100644 (file)
--- a/src/cmd/gc/lex.c
+++ b/src/cmd/gc/lex.c
@@ -33,19 +33,6 @@ static char *goos, *goarch, *goroot;
 
 #define        BOM     0xFEFF
 
-// Compiler experiments.
-// These are controlled by the GOEXPERIMENT environment
-// variable recorded when the compiler is built.
-static struct {
-       char *name;
-       int *val;
-} exper[] = {
-//     {"rune32", &rune32},
-       {"fieldtrack", &fieldtrack_enabled},
-       {"precisestack", &precisestack_enabled},
-       {nil, nil},
-};
-
 // Debug arguments.
 // These can be specified with the -d flag, as in "-d nil"
 // to set the debug_checknil variable. In general the list passed
@@ -55,55 +42,8 @@ static struct {
        int *val;
 } debugtab[] = {
        {"nil", &debug_checknil},
-       {nil, nil},
 };
 
-static void
-addexp(char *s)
-{
-       int i;
-
-       for(i=0; exper[i].name != nil; i++) {
-               if(strcmp(exper[i].name, s) == 0) {
-                       *exper[i].val = 1;
-                       return;
-               }
-       }
-       
-       print("unknown experiment %s\n", s);
-       exits("unknown experiment");
-}
-
-static void
-setexp(void)
-{
-       char *f[20];
-       int i, nf;
-
-       precisestack_enabled = 1; // on by default
-
-       // cmd/dist #defines GOEXPERIMENT for us.
-       nf = getfields(GOEXPERIMENT, f, nelem(f), 1, ",");
-       for(i=0; i<nf; i++)
-               addexp(f[i]);
-}
-
-char*
-expstring(void)
-{
-       int i;
-       static char buf[512];
-
-       strcpy(buf, "X");
-       for(i=0; exper[i].name != nil; i++)
-               if(*exper[i].val)
-                       seprint(buf+strlen(buf), buf+sizeof buf, ",%s", exper[i].name);
-       if(strlen(buf) == 1)
-               strcpy(buf, "X,none");
-       buf[1] = ':';
-       return buf;
-}
-
 // Our own isdigit, isspace, isalpha, isalnum that take care 
 // of EOF and other out of range arguments.
 static int
@@ -272,8 +212,6 @@ main(int argc, char *argv[])
        if(nacl)
                flag_largemodel = 1;
 
-       setexp();
-       
        fmtstrinit(&pragcgobuf);
        quotefmtinstall();
 
@@ -344,13 +282,14 @@ main(int argc, char *argv[])
                
                nf = getfields(debugstr, f, nelem(f), 1, ",");
                for(i=0; i<nf; i++) {
-                       for(j=0; debugtab[j].name != nil; j++) {
+                       for(j=0; j<nelem(debugtab); j++) {
                                if(strcmp(debugtab[j].name, f[i]) == 0) {
-                                       *debugtab[j].val = 1;
+                                       if(debugtab[j].val != nil)
+                                               *debugtab[j].val = 1;
                                        break;
                                }
                        }
-                       if(debugtab[j].name == nil)
+                       if(j >= nelem(debugtab))
                                sysfatal("unknown debug information -d '%s'\n", f[i]);
                }
        }

diff --git a/src/cmd/gc/plive.c b/src/cmd/gc/plive.c
index 3bfa69b1f02084078f8e1ea6b7444bc08d858933..e22d756cedb686ef41868d08c4f7dbd35a66a285 100644 (file)
--- a/src/cmd/gc/plive.c
+++ b/src/cmd/gc/plive.c
@@ -1487,25 +1487,21 @@ livenessepilogue(Liveness *lv)
                                // Annotate ambiguously live variables so that they can
                                // be zeroed at function entry.
                                // livein and liveout are dead here and used as temporaries.
-                               // For now, only enabled when using GOEXPERIMENT=precisestack
-                               // during make.bash / all.bash.
-                               if(precisestack_enabled) {
-                                       bvresetall(livein);
-                                       bvandnot(liveout, any, all);
-                                       if(!bvisempty(liveout)) {
-                                               for(pos = 0; pos < liveout->n; pos++) {
-                                                       if(!bvget(liveout, pos))
-                                                               continue;
-                                                       bvset(all, pos); // silence future warnings in this block
-                                                       n = *(Node**)arrayget(lv->vars, pos);
-                                                       if(!n->needzero) {
-                                                               n->needzero = 1;
-                                                               if(debuglive >= 1)
-                                                                       warnl(p->lineno, "%N: %lN is ambiguously live", curfn->nname, n);
-                                                               // Record in 'ambiguous' bitmap.
-                                                               xoffset = n->xoffset + stkptrsize;
-                                                               twobitwalktype1(n->type, &xoffset, ambig);
-                                                       }
+                               bvresetall(livein);
+                               bvandnot(liveout, any, all);
+                               if(!bvisempty(liveout)) {
+                                       for(pos = 0; pos < liveout->n; pos++) {
+                                               if(!bvget(liveout, pos))
+                                                       continue;
+                                               bvset(all, pos); // silence future warnings in this block
+                                               n = *(Node**)arrayget(lv->vars, pos);
+                                               if(!n->needzero) {
+                                                       n->needzero = 1;
+                                                       if(debuglive >= 1)
+                                                               warnl(p->lineno, "%N: %lN is ambiguously live", curfn->nname, n);
+                                                       // Record in 'ambiguous' bitmap.
+                                                       xoffset = n->xoffset + stkptrsize;
+                                                       twobitwalktype1(n->type, &xoffset, ambig);
                                                }
                                        }
                                }

diff --git a/src/cmd/gc/walk.c b/src/cmd/gc/walk.c
index 48dd17a6af129c51ae23f62133f2456a047b699e..1d2dcf744765a4e952b3de328ce227d518860627 100644 (file)
--- a/src/cmd/gc/walk.c
+++ b/src/cmd/gc/walk.c
@@ -2521,9 +2521,9 @@ paramstoheap(Type **argin, int out)
                v = t->nname;
                if(v && v->sym && v->sym->name[0] == '~' && v->sym->name[1] == 'r') // unnamed result
                        v = N;
-               // In precisestack mode, the garbage collector assumes results
+               // For precise stacks, the garbage collector assumes results
                // are always live, so zero them always.
-               if(out && (precisestack_enabled || (v == N && hasdefer))) {
+               if(out) {
                        // Defer might stop a panic and show the
                        // return values as they exist at the time of panic.
                        // Make sure to zero them on entry to the function.

diff --git a/src/liblink/go.c b/src/liblink/go.c
index 9f5a423d3881e81f44351d1568db5b22498a016b..e31c71ab9263cbe05b3d9b771cbb0ad40cbed7aa 100644 (file)
--- a/src/liblink/go.c
+++ b/src/liblink/go.c
@@ -9,6 +9,66 @@
 #include <bio.h>
 #include <link.h>
 
+int framepointer_enabled;
+int fieldtrack_enabled;
+
+// Toolchain experiments.
+// These are controlled by the GOEXPERIMENT environment
+// variable recorded when the toolchain is built.
+// This list is also known to cmd/gc.
+static struct {
+       char *name;
+       int *val;
+} exper[] = {
+       {"fieldtrack", &fieldtrack_enabled},
+       {"basepointer", &framepointer_enabled}, 
+};
+
+static void
+addexp(char *s)
+{
+       int i;
+
+       for(i=0; i < nelem(exper); i++ ) {
+               if(strcmp(exper[i].name, s) == 0) {
+                       if(exper[i].val != nil)
+                               *exper[i].val = 1;
+                       return;
+               }
+       }
+       
+       print("unknown experiment %s\n", s);
+       exits("unknown experiment");
+}
+
+void
+linksetexp(void)
+{
+       char *f[20];
+       int i, nf;
+
+       // cmd/dist #defines GOEXPERIMENT for us.
+       nf = getfields(GOEXPERIMENT, f, nelem(f), 1, ",");
+       for(i=0; i<nf; i++)
+               addexp(f[i]);
+}
+
+char*
+expstring(void)
+{
+       int i;
+       static char buf[512];
+
+       strcpy(buf, "X");
+       for(i=0; i<nelem(exper); i++)
+               if(*exper[i].val)
+                       seprint(buf+strlen(buf), buf+sizeof buf, ",%s", exper[i].name);
+       if(strlen(buf) == 1)
+               strcpy(buf, "X,none");
+       buf[1] = ':';
+       return buf;
+}
+
 // replace all "". with pkg.
 char*
 expandpkg(char *t0, char *pkg)

diff --git a/src/liblink/sym.c b/src/liblink/sym.c
index e06837118a30ce3d2a55369783fae391cd4cb495..35b88f44a2267b80adb9743331929771c167b129 100644 (file)
--- a/src/liblink/sym.c
+++ b/src/liblink/sym.c
@@ -90,6 +90,7 @@ linknew(LinkArch *arch)
        char *p;
        char buf[1024];
 
+       linksetexp();
        nuxiinit(arch);
        
        ctxt = emallocz(sizeof *ctxt);

diff --git a/src/runtime/proc1.go b/src/runtime/proc1.go
index 6fa407f0ce2f29e01e150994955a611218a9a10f..1950403329fb6eb7d75b4791f21f5d158a16112f 100644 (file)
--- a/src/runtime/proc1.go
+++ b/src/runtime/proc1.go
@@ -3163,8 +3163,6 @@ func setMaxThreads(in int) (out int) {
        return
 }
 
-var goexperiment string = "GOEXPERIMENT" // TODO: defined in zaexperiment.h
-
 func haveexperiment(name string) bool {
        x := goexperiment
        for x != "" {