================
@@ -216,6 +228,35 @@ u64 GetShadowCount(uptr p, u32 size) {
return count;
}
+// Accumulates the access count from the shadow for the given pointer and size.
+// See memprof_mapping.h for an overview on histogram counters.
+u64 GetShadowCountHistogram(uptr p, u32 size) {
+ u8 *shadow = (u8 *)HISTOGRAM_MEM_TO_SHADOW(p);
+ u8 *shadow_end = (u8 *)HISTOGRAM_MEM_TO_SHADOW(p + size);
+ u64 count = 0;
+ for (; shadow <= shadow_end; shadow++)
+ count += *shadow;
+ return count;
+}
+
+// If we use the normal approach from clearCountersWithoutHistogram, the
+// histogram will clear too much data and may overwrite shadow counters that
are
+// in use. Likely because of rounding up the shadow_end pointer.
+// See memprof_mapping.h for an overview on histogram counters.
+void clearCountersHistogram(uptr addr, uptr size) {
+ u8 *shadow_8 = (u8 *)HISTOGRAM_MEM_TO_SHADOW(addr);
+ u8 *shadow_end_8 = (u8 *)HISTOGRAM_MEM_TO_SHADOW(addr + size);
+ for (; shadow_8 < shadow_end_8; shadow_8++) {
+ *shadow_8 = 0;
+ }
+}
+
+void clearCountersWithoutHistogram(uptr addr, uptr size) {
+ uptr shadow_beg = MEM_TO_SHADOW(addr);
+ uptr shadow_end = MEM_TO_SHADOW(addr + size - SHADOW_GRANULARITY) + 1;
+ REAL(memset)((void *)shadow_beg, 0, shadow_end - shadow_beg);
+}
+
// Clears the shadow counters (when memory is allocated).
void ClearShadow(uptr addr, uptr size) {
----------------
mattweingarten wrote:
This function uses the MEM_TO_SHADOW computed pointers "kind of", but in
reality it just rounds these pointers up to nearest page_sizes. So in effect,
full pages should be cleared no matter if it is with histogram or without.
https://github.com/llvm/llvm-project/pull/94264
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