go: replace PC jumps with labels

Rewrite PC jumps with labels so that it's clear where the jumps are to.

1 files changed, 97 insertions, 16 deletions

diff --git a/lib/compilers/golang.js b/lib/compilers/golang.js
index bbf666576..f558c5eb3 100644
--- a/lib/compilers/golang.js
+++ b/lib/compilers/golang.js
@@ -26,38 +26,119 @@ const BaseCompiler = require('../base-compiler'),
     _ = require('underscore'),
     utils = require('../utils');
 
+// Each arch has a list of jump instructions in
+// Go source src/cmd/asm/internal/arch.
+const jumpPrefixes = [
+    'j',
+    'b',
+
+    // arm
+    'cb',
+    'tb',
+
+    // s390x
+    'cmpb',
+    'cmpub'
+];
+
 class GolangCompiler extends BaseCompiler {
     convertNewGoL(code) {
-        const re = /^\s+(0[xX]?[0-9A-Za-z]+)?\s?[0-9]+\s*\(([^:]+):([0-9]+)\)\s*([A-Z]+)(.*)/;
-        const reUnknown = /^\s+(0[xX]?[0-9A-Za-z]+)?\s?[0-9]+\s*\(<unknown line number>\)\s*([A-Z]+)(.*)/;
+        const re = /^\s+(0[xX]?[0-9A-Za-z]+)?\s?([0-9]+)\s*\(([^:]+):([0-9]+)\)\s*([A-Z]+)(.*)/;
+        const reUnknown = /^\s+(0[xX]?[0-9A-Za-z]+)?\s?([0-9]+)\s*\(<unknown line number>\)\s*([A-Z]+)(.*)/;
+        const reFunc = /TEXT\s+[".]*(\S+)\(SB\)/;
         let prevLine = null;
         let file = null;
         let fileCount = 0;
-        return _.compact(code.map(obj => {
+        let func = null;
+        let labels = {};
+        let usedLabels = {};
+        let lines = code.map(obj => {
+            let pcMatch = null;
+            let fileMatch = null;
+            let lineMatch = null;
+            let ins = null;
+            let args = null;
+
             const line = obj.text;
             let match = line.match(re);
             if (match) {
-                let res = "";
-                if (file !== match[2]) {
-                    fileCount++;
-                    res += "\t.file " + fileCount + ' "' + match[2] + '"\n';
-                    file = match[2];
-                }
-                if (prevLine !== match[3]) {
-                    res += "\t.loc " + fileCount + " " + match[3] + " 0\n";
-                    prevLine = match[3];
-                }
-                return res + "\t" + match[4].toLowerCase() + match[5];
+                pcMatch = match[2];
+                fileMatch = match[3];
+                lineMatch = match[4];
+                ins = match[5];
+                args = match[6];
             } else {
                 match = line.match(reUnknown);
                 if (match) {
-                    return "\t" + match[2].toLowerCase() + match[3];
+                    pcMatch = match[2];
+                    ins = match[3];
+                    args = match[4];
                 } else {
                     return null;
                 }
             }
 
-        })).join("\n");
+            match = line.match(reFunc);
+            if (match) {
+                // Normalize function name.
+                func = match[1].replace(/[.()*]+/g, "_");
+            }
+
+            let res = [];
+            if (pcMatch && !labels[pcMatch]) {
+                // Create pseudo-label.
+                let label = pcMatch.replace(/^0{0,4}/, '');
+                label = `${func}_pc${label}:`;
+                if (!labels[label]) {
+                    res.push(label);
+                    labels[label] = true;
+                }
+            }
+
+            if (fileMatch && file !== fileMatch) {
+                fileCount++;
+                res.push(`\t.file ${fileCount} "${fileMatch}"`);
+                file = fileMatch;
+            }
+
+            if (lineMatch && prevLine !== lineMatch) {
+                res.push(`\t.loc ${fileCount} ${lineMatch} 0`);
+                prevLine = lineMatch;
+            }
+
+            ins = ins.toLowerCase();
+            args = this.replaceJump(func, ins, args, usedLabels);
+            res.push(`\t${ins}${args}`);
+            return res;
+        });
+
+        // Find unused pseudo-labels so they can be filtered out.
+        let unusedLabels = _.mapObject(labels, (val, key) => { return !usedLabels[key]; });
+
+        return _.chain(lines)
+            .flatten()
+            .compact()
+            .filter((line) => { return !unusedLabels[line]; })
+            .value()
+            .join("\n");
+    }
+
+    replaceJump(func, ins, args, usedLabels) {
+        // Check if last argument is a decimal number.
+        const re = /(\s+)([0-9]+)(\s?)$/;
+        let match = args.match(re);
+        if (!match) {
+            return args;
+        }
+
+        // Check instruction has a jump prefix
+        if (_.any(jumpPrefixes, (prefix) => { return ins.startsWith(prefix); })) {
+            let label = `${func}_pc${match[2]}`;
+            usedLabels[label + ":"] = true; // record label use for later filtering
+            return `${match[1]}${label}${match[3]}`;
+        }
+
+        return args;
     }
 
     extractLogging(stdout) {