flags and hacks to get MSAN bot going

This disables a few tests in DM:
   - one BlurLargeImage GM maybe is really broken
   - FontMgrAndroidParser uses libexpat, which I've not (yet?) built from source,
     so MSAN can't see into it.

This extends some of the MSAN stifling we added around SkImageDecoder_libjpeg to SkCodec, and skips .wbmps, .pngs, and .bmps.  We're only seeing issues in colortables for .png and .bmp.

I think I can probably back out disabling Codec and the RAW image decodes...
they should all be covered by the libjpeg stifles.

BUG=skia:4550,skia:4900
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1673663002

CQ_EXTRA_TRYBOTS=client.skia:Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-SKNX_NO_SIMD-Trybot,Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Debug-MSAN-Trybot

TBR=msarett@google.com

Review URL: https://codereview.chromium.org/1673663002

3 files changed, 25 insertions, 6 deletions

diff --git a/src/codec/SkJpegCodec.cpp b/src/codec/SkJpegCodec.cpp
index 112078b97c..aefe264f1a 100644
--- a/src/codec/SkJpegCodec.cpp
+++ b/src/codec/SkJpegCodec.cpp
@@ -6,6 +6,7 @@
  */
 
 #include "SkCodec.h"
+#include "SkMSAN.h"
 #include "SkJpegCodec.h"
 #include "SkJpegDecoderMgr.h"
 #include "SkJpegUtility_codec.h"
@@ -215,7 +216,7 @@ bool SkJpegCodec::setOutputColorSpace(const SkImageInfo& dst) {
 }
 
 /*
- * Checks if we can natively scale to the requested dimensions and natively scales the 
+ * Checks if we can natively scale to the requested dimensions and natively scales the
  * dimensions if possible
  */
 bool SkJpegCodec::onDimensionsSupported(const SkISize& size) {
@@ -308,6 +309,7 @@ SkCodec::Result SkJpegCodec::onGetPixels(const SkImageInfo& dstInfo,
     for (uint32_t y = 0; y < dstHeight; y++) {
         // Read rows of the image
         uint32_t lines = jpeg_read_scanlines(dinfo, &dstRow, 1);
+        sk_msan_mark_initialized(dstRow, dstRow + dstRowBytes, "skbug.com/4550");
 
         // If we cannot read enough rows, assume the input is incomplete
         if (lines != 1) {
@@ -399,24 +401,27 @@ SkCodec::Result SkJpegCodec::onStartScanlineDecode(const SkImageInfo& dstInfo,
     return kSuccess;
 }
 
-int SkJpegCodec::onGetScanlines(void* dst, int count, size_t rowBytes) {
+int SkJpegCodec::onGetScanlines(void* dst, int count, size_t dstRowBytes) {
     // Set the jump location for libjpeg errors
     if (setjmp(fDecoderMgr->getJmpBuf())) {
         return fDecoderMgr->returnFailure("setjmp", kInvalidInput);
     }
     // Read rows one at a time
     JSAMPLE* dstRow;
+    size_t srcRowBytes = get_row_bytes(fDecoderMgr->dinfo());
     if (fSwizzler) {
         // write data to storage row, then sample using swizzler
         dstRow = fSrcRow;
     } else {
         // write data directly to dst
+        SkASSERT(count == 1 || dstRowBytes >= srcRowBytes);
         dstRow = (JSAMPLE*) dst;
     }
 
     for (int y = 0; y < count; y++) {
         // Read row of the image
         uint32_t rowsDecoded = jpeg_read_scanlines(fDecoderMgr->dinfo(), &dstRow, 1);
+        sk_msan_mark_initialized(dstRow, dstRow + srcRowBytes, "skbug.com/4550");
         if (rowsDecoded != 1) {
             fDecoderMgr->dinfo()->output_scanline = this->dstInfo().height();
             return y;
@@ -425,9 +430,9 @@ int SkJpegCodec::onGetScanlines(void* dst, int count, size_t rowBytes) {
         if (fSwizzler) {
             // use swizzler to sample row
             fSwizzler->swizzle(dst, dstRow);
-            dst = SkTAddOffset<JSAMPLE>(dst, rowBytes);
+            dst = SkTAddOffset<JSAMPLE>(dst, dstRowBytes);
         } else {
-            dstRow = SkTAddOffset<JSAMPLE>(dstRow, rowBytes);
+            dstRow = SkTAddOffset<JSAMPLE>(dstRow, dstRowBytes);
         }
     }
     return count;
diff --git a/src/images/SkImageDecoder_libjpeg.cpp b/src/images/SkImageDecoder_libjpeg.cpp
index 6a3ae87b6a..89bfefcd45 100644
--- a/src/images/SkImageDecoder_libjpeg.cpp
+++ b/src/images/SkImageDecoder_libjpeg.cpp
@@ -509,6 +509,8 @@ SkImageDecoder::Result SkJPEGImageDecoder::onDecode(SkStream* stream, SkBitmap*
     for (int y = 0;; y++) {
         JSAMPLE* rowptr = (JSAMPLE*)srcRow;
         int row_count = jpeg_read_scanlines(&cinfo, &rowptr, 1);
+        sk_msan_mark_initialized(srcRow, srcRow + cinfo.output_width * srcBytesPerPixel,
+                                 "skbug.com/4550");
         if (0 == row_count) {
             // if row_count == 0, then we didn't get a scanline,
             // so return early.  We will return a partial image.
@@ -525,8 +527,6 @@ SkImageDecoder::Result SkJPEGImageDecoder::onDecode(SkStream* stream, SkBitmap*
             convert_CMYK_to_RGB(srcRow, cinfo.output_width);
         }
 
-        sk_msan_mark_initialized(srcRow, srcRow + cinfo.output_width * srcBytesPerPixel,
-                                 "skbug.com/4550");
 
         sampler.next(srcRow);
         if (bm->height() - 1 == y) {
diff --git a/src/opts/SkXfermode_opts.h b/src/opts/SkXfermode_opts.h
index f15094c98b..31817f5f61 100644
--- a/src/opts/SkXfermode_opts.h
+++ b/src/opts/SkXfermode_opts.h
@@ -9,6 +9,7 @@
 #define Sk4pxXfermode_DEFINED
 
 #include "Sk4px.h"
+#include "SkMSAN.h"
 #include "SkNx.h"
 #include "SkXfermode_proccoeff.h"
 
@@ -202,6 +203,17 @@ XFERMODE_AA(Plus) {  // [ clamp( (1-AA)D + (AA)(S+D) ) == clamp(D + AA*S) ]
 
 #undef XFERMODE_AA
 
+// Src and Clear modes are safe to use with unitialized dst buffers,
+// even if the implementation branches based on bytes from dst (e.g. asserts in Debug mode).
+// For those modes, just lie to MSAN that dst is always intialized.
+template <typename Xfermode> static void mark_dst_initialized_if_safe(void*, void*) {}
+template <> void mark_dst_initialized_if_safe<Src>(void* dst, void* end) {
+    sk_msan_mark_initialized(dst, end, "Src doesn't read dst.");
+}
+template <> void mark_dst_initialized_if_safe<Clear>(void* dst, void* end) {
+    sk_msan_mark_initialized(dst, end, "Clear doesn't read dst.");
+}
+
 template <typename Xfermode>
 class Sk4pxXfermode : public SkProcCoeffXfermode {
 public:
@@ -209,6 +221,7 @@ public:
         : INHERITED(rec, mode) {}
 
     void xfer32(SkPMColor dst[], const SkPMColor src[], int n, const SkAlpha aa[]) const override {
+        mark_dst_initialized_if_safe<Xfermode>(dst, dst+n);
         if (nullptr == aa) {
             Sk4px::MapDstSrc(n, dst, src, Xfermode());
         } else {
@@ -217,6 +230,7 @@ public:
     }
 
     void xfer16(uint16_t dst[], const SkPMColor src[], int n, const SkAlpha aa[]) const override {
+        mark_dst_initialized_if_safe<Xfermode>(dst, dst+n);
         SkPMColor dst32[4];
         while (n >= 4) {
             dst32[0] = SkPixel16ToPixel32(dst[0]);