[val] Add extra context to error messages. (#1600)

[val] Add extra context to error messages.

This CL extends the error messages produced by the validator to output the
disassembly of the errored line.

The validation_id messages have also been updated to print the line number of
the error instead of the word number. Note, the error number is from the start
of the SPIR-V, it does not include any headers printed in the disassembled code.

Fixes #670, #1581

2 files changed, 8 insertions, 4 deletions

diff --git a/tools/io.h b/tools/io.h
index 690b5c36..637ae5bc 100644
--- a/tools/io.h
+++ b/tools/io.h
@@ -39,7 +39,10 @@ bool ReadFile(const char* filename, const char* mode, std::vector<T>* data) {
       }
     } else {
       if (sizeof(T) != 1 && (ftell(fp) % sizeof(T))) {
-        fprintf(stderr, "error: corrupted word found in file '%s'\n", filename);
+        fprintf(
+            stderr,
+            "error: file size should be a multiple of %zd; file '%s' corrupt\n",
+            sizeof(T), filename);
         return false;
       }
     }
diff --git a/tools/val/val.cpp b/tools/val/val.cpp
index 7c215e4d..ca16f2dd 100644
--- a/tools/val/val.cpp
+++ b/tools/val/val.cpp
@@ -163,15 +163,16 @@ int main(int argc, char** argv) {
       case SPV_MSG_FATAL:
       case SPV_MSG_INTERNAL_ERROR:
       case SPV_MSG_ERROR:
-        std::cerr << "error: " << position.index << ": " << message
+        std::cerr << "error: line " << position.index << ": " << message
                   << std::endl;
         break;
       case SPV_MSG_WARNING:
-        std::cout << "warning: " << position.index << ": " << message
+        std::cout << "warning: line " << position.index << ": " << message
                   << std::endl;
         break;
       case SPV_MSG_INFO:
-        std::cout << "info: " << position.index << ": " << message << std::endl;
+        std::cout << "info: line " << position.index << ": " << message
+                  << std::endl;
         break;
       default:
         break;