Commit 2d005827b8

@@ -147,7 +147,6 @@
         <li>Total Runs: <span id="statTotalRuns"></span></li>
         <li>Unique Runs: <span id="statUniqueRuns"></span></li>
         <li>Coverage: <span id="statCoverage"></span></li>
-        <li>Lowest Stack: <span id="statLowestStack"></span></li>
         <li>Entry Points: <ul id="entryPointsList"></ul></li>
       </ul>
     </div>

@@ -6,7 +6,6 @@
   const domStatTotalRuns = document.getElementById("statTotalRuns");
   const domStatUniqueRuns = document.getElementById("statUniqueRuns");
   const domStatCoverage = document.getElementById("statCoverage");
-  const domStatLowestStack = document.getElementById("statLowestStack");
   const domEntryPointsList = document.getElementById("entryPointsList");
 
   let wasm_promise = fetch("main.wasm");
@@ -158,7 +157,6 @@
     domStatTotalRuns.innerText = totalRuns;
     domStatUniqueRuns.innerText = uniqueRuns + " (" + percent(uniqueRuns, totalRuns) + "%)";
     domStatCoverage.innerText = coveredSourceLocations + " / " + totalSourceLocations + " (" + percent(coveredSourceLocations, totalSourceLocations) + "%)";
-    domStatLowestStack.innerText = unwrapString(wasm_exports.lowestStack());
 
     const entryPoints = unwrapInt32Array(wasm_exports.entryPoints());
     resizeDomList(domEntryPointsList, entryPoints.length, "<li></li>");

@@ -106,13 +106,6 @@ export fn decl_source_html(decl_index: Decl.Index) String {
     return String.init(string_result.items);
 }
 
-export fn lowestStack() String {
-    const header: *abi.CoverageUpdateHeader = @ptrCast(recent_coverage_update.items[0..@sizeOf(abi.CoverageUpdateHeader)]);
-    string_result.clearRetainingCapacity();
-    string_result.writer(gpa).print("0x{d}", .{header.lowest_stack}) catch @panic("OOM");
-    return String.init(string_result.items);
-}
-
 export fn totalSourceLocations() usize {
     return coverage_source_locations.items.len;
 }

@@ -13,7 +13,6 @@ pub const SeenPcsHeader = extern struct {
     n_runs: usize,
     unique_runs: usize,
     pcs_len: usize,
-    lowest_stack: usize,
 
     /// Used for comptime assertions. Provides a mechanism for strategically
     /// causing compile errors.
@@ -79,7 +78,6 @@ pub const CoverageUpdateHeader = extern struct {
     flags: Flags = .{},
     n_runs: u64,
     unique_runs: u64,
-    lowest_stack: u64,
 
     pub const Flags = packed struct(u64) {
         tag: ToClientTag = .coverage_update,

@@ -406,7 +406,6 @@ fn sendCoverageContext(
     const seen_pcs = cov_header.seenBits();
     const n_runs = @atomicLoad(usize, &cov_header.n_runs, .monotonic);
     const unique_runs = @atomicLoad(usize, &cov_header.unique_runs, .monotonic);
-    const lowest_stack = @atomicLoad(usize, &cov_header.lowest_stack, .monotonic);
     if (prev_unique_runs.* != unique_runs) {
         // There has been an update.
         if (prev_unique_runs.* == 0) {
@@ -431,7 +430,6 @@ fn sendCoverageContext(
         const header: abi.CoverageUpdateHeader = .{
             .n_runs = n_runs,
             .unique_runs = unique_runs,
-            .lowest_stack = lowest_stack,
         };
         const iovecs: [2]std.posix.iovec_const = .{
             makeIov(std.mem.asBytes(&header)),

@@ -28,7 +28,8 @@ fn logOverride(
     f.writer().print(prefix1 ++ prefix2 ++ format ++ "\n", args) catch @panic("failed to write to fuzzer log");
 }
 
-export threadlocal var __sancov_lowest_stack: usize = std.math.maxInt(usize);
+/// Helps determine run uniqueness in the face of recursion.
+export threadlocal var __sancov_lowest_stack: usize = 0;
 
 export fn __sanitizer_cov_trace_const_cmp1(arg1: u8, arg2: u8) void {
     handleCmp(@returnAddress(), arg1, arg2);
@@ -220,7 +221,6 @@ const Fuzzer = struct {
                 .n_runs = 0,
                 .unique_runs = 0,
                 .pcs_len = pcs.len,
-                .lowest_stack = std.math.maxInt(usize),
             };
             f.seen_pcs.appendSliceAssumeCapacity(std.mem.asBytes(&header));
             f.seen_pcs.appendNTimesAssumeCapacity(0, n_bitset_elems * @sizeOf(usize));
@@ -261,8 +261,8 @@ const Fuzzer = struct {
             f.input.appendSliceAssumeCapacity(run.input);
             try f.mutate();
 
-            _ = @atomicRmw(usize, &header.lowest_stack, .Min, __sancov_lowest_stack, .monotonic);
             @memset(f.pc_counters, 0);
+            __sancov_lowest_stack = std.math.maxInt(usize);
             f.coverage.reset();
 
             fuzzer_one(f.input.items.ptr, f.input.items.len);