cmd/ld: better diagnostics on unaligned symbols

Want to see why builders are failing.
Then decide whether to rollback or fix.

TBR=khr
R=khr
CC=golang-codereviews
https://golang.org/cl/114510043

diff --git a/src/cmd/ld/data.c b/src/cmd/ld/data.c
index e8e697f15ed8e1f7ad35e8915ba6028b19122aca..96eadd479ad1244010e46489725ea30b17c9d6ec 100644 (file)
--- a/src/cmd/ld/data.c
+++ b/src/cmd/ld/data.c
@@ -815,7 +815,8 @@ proggenaddsym(ProgGen *g, LSym *s)
        if(s->gotype == nil && s->size >= PtrSize) {
                // conservative scan
                if((s->size%PtrSize) || (g->pos%PtrSize))
-                       diag("proggenaddsym: unaligned symbol");
+                       diag("proggenaddsym: unaligned conservative symbol %s: size=%lld pos=%lld",
+                               s->name, s->size, g->pos);
                size = (s->size+PtrSize-1)/PtrSize*PtrSize;
                if(size < 32*PtrSize) {
                        // Emit small symbols as data.
@@ -840,7 +841,8 @@ proggenaddsym(ProgGen *g, LSym *s)
                } else {
                        // Emit large symbols as array.
                        if((s->size%PtrSize) || (g->pos%PtrSize))
-                               diag("proggenaddsym: unaligned symbol");
+                               diag("proggenaddsym: unaligned noscan symbol %s: size=%lld pos=%lld",
+                                       s->name, s->size, g->pos);
                        proggenarray(g, s->size/PtrSize);
                        proggendata(g, BitsScalar);
                        proggenarrayend(g);
@@ -852,7 +854,8 @@ proggenaddsym(ProgGen *g, LSym *s)
                gcprog = decodetype_gcprog(s->gotype);
                size = decodetype_size(s->gotype);
                if((size%PtrSize) || (g->pos%PtrSize))
-                       diag("proggenaddsym: unaligned symbol");
+                       diag("proggenaddsym: unaligned gcprog symbol %s: size=%lld pos=%lld",
+                               s->name, s->size, g->pos);
                for(i = 0; i < gcprog->np-1; i++)
                        proggenemit(g, gcprog->p[i]);
                g->pos = s->value + size;
@@ -861,7 +864,8 @@ proggenaddsym(ProgGen *g, LSym *s)
                mask = decodetype_gcmask(s->gotype);
                size = decodetype_size(s->gotype);
                if((size%PtrSize) || (g->pos%PtrSize))
-                       diag("proggenaddsym: unaligned symbol");
+                       diag("proggenaddsym: unaligned gcmask symbol %s: size=%lld pos=%lld",
+                               s->name, s->size, g->pos);
                for(i = 0; i < size; i += PtrSize)
                        proggendata(g, (mask[i/PtrSize/2]>>((i/PtrSize%2)*4+2))&BitsMask);
                g->pos = s->value + size;