cmd/cc, runtime: disallow structs without tags

Structs without tags have no unique name to use in the
Go definitions generated from the C types.
This caused issue 8812, fixed by CL 149260043.
Avoid future problems by requiring struct tags.

Update runtime as needed.
(There is no other C code in the tree.)

LGTM=bradfitz, iant
R=golang-codereviews, bradfitz, dave, iant
CC=golang-codereviews, khr, r
https://golang.org/cl/150360043

5 files changed, 18 insertions, 16 deletions

diff --git a/src/runtime/malloc.h b/src/runtime/malloc.h
index b90f1baf29..d1930756a2 100644
--- a/src/runtime/malloc.h
+++ b/src/runtime/malloc.h
@@ -273,7 +273,8 @@ struct MStats
 	bool	debuggc;
 
 	// Statistics about allocation size classes.
-	struct {
+	
+	struct MStatsBySize {
 		uint32 size;
 		uint64 nmalloc;
 		uint64 nfree;
@@ -282,6 +283,7 @@ struct MStats
 	uint64	tinyallocs;	// number of tiny allocations that didn't cause actual allocation; not exported to Go directly
 };
 
+
 #define mstats runtime·memstats
 extern MStats mstats;
 void	runtime·updatememstats(GCStats *stats);
@@ -489,7 +491,7 @@ struct MHeap
 	// the padding makes sure that the MCentrals are
 	// spaced CacheLineSize bytes apart, so that each MCentral.lock
 	// gets its own cache line.
-	struct {
+	struct MHeapCentral {
 		MCentral mcentral;
 		byte pad[CacheLineSize];
 	} central[NumSizeClasses];
diff --git a/src/runtime/os_plan9.h b/src/runtime/os_plan9.h
index 7ebaa9c0c6..6d18024834 100644
--- a/src/runtime/os_plan9.h
+++ b/src/runtime/os_plan9.h
@@ -63,7 +63,7 @@ typedef struct Tos Tos;
 typedef intptr _Plink;
 
 struct Tos {
-	struct			/* Per process profiling */
+	struct TosProf			/* Per process profiling */
 	{
 		_Plink	*pp;	/* known to be 0(ptr) */
 		_Plink	*next;	/* known to be 4(ptr) */
diff --git a/src/runtime/proc.c b/src/runtime/proc.c
index e84dc1d048..1426790f40 100644
--- a/src/runtime/proc.c
+++ b/src/runtime/proc.c
@@ -2421,7 +2421,7 @@ runtime·mcount(void)
 	return runtime·sched.mcount;
 }
 
-static struct {
+static struct ProfState {
 	uint32 lock;
 	int32 hz;
 } prof;
diff --git a/src/runtime/runtime.h b/src/runtime/runtime.h
index aa300d7bb8..c4d8786089 100644
--- a/src/runtime/runtime.h
+++ b/src/runtime/runtime.h
@@ -384,11 +384,11 @@ struct	M
 	// these are here because they are too large to be on the stack
 	// of low-level NOSPLIT functions.
 	LibCall	libcall;
-	struct {
+	struct MTs {
 		int64	tv_sec;
 		int64	tv_nsec;
 	} ts;
-	struct {
+	struct MScratch {
 		uintptr v[6];
 	} scratch;
 #endif
diff --git a/src/runtime/vdso_linux_amd64.c b/src/runtime/vdso_linux_amd64.c
index 41a41fdd6a..681340c5b6 100644
--- a/src/runtime/vdso_linux_amd64.c
+++ b/src/runtime/vdso_linux_amd64.c
@@ -52,7 +52,7 @@ typedef uint16 Elf64_Section;
 typedef Elf64_Half Elf64_Versym;
 
 
-typedef struct
+typedef struct Elf64_Sym
 {
 	Elf64_Word st_name;
 	byte st_info;
@@ -62,7 +62,7 @@ typedef struct
 	Elf64_Xword st_size;
 } Elf64_Sym;
 
-typedef struct
+typedef struct Elf64_Verdef
 {
 	Elf64_Half vd_version; /* Version revision */
 	Elf64_Half vd_flags;   /* Version information */
@@ -73,7 +73,7 @@ typedef struct
 	Elf64_Word vd_next;    /* Offset in bytes to next verdef entry */
 } Elf64_Verdef;
 
-typedef struct
+typedef struct Elf64_Ehdr
 {
 	byte e_ident[EI_NIDENT]; /* Magic number and other info */
 	Elf64_Half e_type;       /* Object file type */
@@ -91,7 +91,7 @@ typedef struct
 	Elf64_Half e_shstrndx;   /* Section header string table index */
 } Elf64_Ehdr;
 
-typedef struct
+typedef struct Elf64_Phdr
 {
 	Elf64_Word p_type;    /* Segment type */
 	Elf64_Word p_flags;   /* Segment flags */
@@ -103,7 +103,7 @@ typedef struct
 	Elf64_Xword p_align;  /* Segment alignment */
 } Elf64_Phdr;
 
-typedef struct
+typedef struct Elf64_Shdr
 {
 	Elf64_Word sh_name;       /* Section name (string tbl index) */
 	Elf64_Word sh_type;       /* Section type */
@@ -117,7 +117,7 @@ typedef struct
 	Elf64_Xword sh_entsize;   /* Entry size if section holds table */
 } Elf64_Shdr;
 
-typedef struct
+typedef struct Elf64_Dyn
 {
 	Elf64_Sxword d_tag; /* Dynamic entry type */
 	union
@@ -127,13 +127,13 @@ typedef struct
 	} d_un;
 } Elf64_Dyn;
 
-typedef struct
+typedef struct Elf64_Verdaux
 {
 	Elf64_Word vda_name; /* Version or dependency names */
 	Elf64_Word vda_next; /* Offset in bytes to next verdaux entry */
 } Elf64_Verdaux;
 
-typedef struct
+typedef struct Elf64_auxv_t
 {
 	uint64 a_type;        /* Entry type */
 	union
@@ -143,13 +143,13 @@ typedef struct
 } Elf64_auxv_t;
 
 
-typedef struct {
+typedef struct symbol_key {
 	byte* name;
 	int32 sym_hash;
 	void** var_ptr;
 } symbol_key;
 
-typedef struct {
+typedef struct version_key {
 	byte* version;
 	int32 ver_hash;
 } version_key;