Remapper: make remapper robust against non-exiting error handlers

Remapper errors are generally fatal: there has been some unexpected situation while
parsing the SPV binary, and there is no reasonable way to carry on.  The
errorHandler() function is called in this case, which by default exits, but
it is possible to submit a handler which does not.  In that case the remapper would
carry on in a bad state.

This change ensures a graceful termination of the remap() function.

While a try {} catch {} construct would be the ideal and safe way to do this,
that's off limits for certain environments, so this tries to do the same thing
with explicit code, to catch all the bailout paths.

CMakeLists.txt

@@ -52,7 +52,7 @@ endif(WIN32)
 
 if(${CMAKE_CXX_COMPILER_ID} MATCHES "GNU")
     add_compile_options(-Wall -Wmaybe-uninitialized -Wuninitialized -Wunused -Wunused-local-typedefs
-                        -Wunused-parameter -Wunused-value  -Wunused-variable -Wunused-but-set-parameter -Wunused-but-set-variable)
+                        -Wunused-parameter -Wunused-value  -Wunused-variable -Wunused-but-set-parameter -Wunused-but-set-variable -fno-exceptions)
     add_compile_options(-Wno-reorder)  # disable this from -Wall, since it happens all over.
 elseif(${CMAKE_CXX_COMPILER_ID} MATCHES "Clang")
     add_compile_options(-Wall -Wuninitialized -Wunused -Wunused-local-typedefs

SPIRV/SPVRemapper.cpp

@@ -135,6 +135,9 @@ namespace spv {
         const unsigned typeStart = idPos(id);
         const spv::Op  opCode    = asOpCode(typeStart);
 
+        if (errorLatch)
+            return 0;
+
         switch (opCode) {
         case spv::OpTypeInt:   // fall through...
         case spv::OpTypeFloat: return (spv[typeStart+2]+31)/32;
@@ -148,8 +151,10 @@ namespace spv {
     unsigned spirvbin_t::idTypeSizeInWords(spv::Id id) const
     {
         const auto tid_it = idTypeSizeMap.find(id);
-        if (tid_it == idTypeSizeMap.end())
+        if (tid_it == idTypeSizeMap.end()) {
             error("type size for ID not found");
+            return 0;
+        }
 
         return tid_it->second;
     }
@@ -253,19 +258,31 @@ namespace spv {
     {
         assert(id != spv::NoResult && newId != spv::NoResult);
 
+        if (id > bound()) {
+            error(std::string("ID out of range: ") + std::to_string(id));
+            return spirvbin_t::unused;
+        }
+
         if (id >= idMapL.size())
             idMapL.resize(id+1, unused);
 
         if (newId != unmapped && newId != unused) {
-            if (isOldIdUnused(id))
+            if (isOldIdUnused(id)) {
                 error(std::string("ID unused in module: ") + std::to_string(id));
+                return spirvbin_t::unused;
+            }
 
-            if (!isOldIdUnmapped(id))
+            if (!isOldIdUnmapped(id)) {
                 error(std::string("ID already mapped: ") + std::to_string(id) + " -> "
                         + std::to_string(localId(id)));
 
-            if (isNewIdMapped(newId))
+                return spirvbin_t::unused;
+            }
+
+            if (isNewIdMapped(newId)) {
                 error(std::string("ID already used in module: ") + std::to_string(newId));
+                return spirvbin_t::unused;
+            }
 
             msg(4, 4, std::string("map: ") + std::to_string(id) + " -> " + std::to_string(newId));
             setMapped(newId);
@@ -299,6 +316,10 @@ namespace spv {
         process(inst_fn_nop, // ignore instructions
             [this](spv::Id& id) {
                 id = localId(id);
+
+                if (errorLatch)
+                    return;
+
                 assert(id != unused && id != unmapped);
             }
         );
@@ -317,14 +338,22 @@ namespace spv {
                 continue;
 
             // Find a new mapping for any used but unmapped IDs
-            if (isOldIdUnmapped(id))
+            if (isOldIdUnmapped(id)) {
                 localId(id, unusedId = nextUnusedId(unusedId));
+                if (errorLatch)
+                    return;
+            }
 
-            if (isOldIdUnmapped(id))
+            if (isOldIdUnmapped(id)) {
                 error(std::string("old ID not mapped: ") + std::to_string(id));
+                return;
+            }
 
             // Track max bound
             maxBound = std::max(maxBound, localId(id) + 1);
+
+            if (errorLatch)
+                return;
         }
 
         bound(maxBound); // reset header ID bound to as big as it now needs to be
@@ -406,6 +435,9 @@ namespace spv {
                     if (typeId != spv::NoResult) {
                         const unsigned idTypeSize = typeSizeInWords(typeId);
 
+                        if (errorLatch)
+                            return false;
+
                         if (idTypeSize != 0)
                             idTypeSizeMap[resultId] = idTypeSize;
                     }
@@ -421,17 +453,26 @@ namespace spv {
                 } else if (opCode == spv::Op::OpEntryPoint) {
                     entryPoint = asId(start + 2);
                 } else if (opCode == spv::Op::OpFunction) {
-                    if (fnStart != 0)
+                    if (fnStart != 0) {
                         error("nested function found");
+                        return false;
+                    }
+
                     fnStart = start;
                     fnRes   = asId(start + 2);
                 } else if (opCode == spv::Op::OpFunctionEnd) {
                     assert(fnRes != spv::NoResult);
-                    if (fnStart == 0)
+                    if (fnStart == 0) {
                         error("function end without function start");
+                        return false;
+                    }
+
                     fnPos[fnRes] = range_t(fnStart, start + asWordCount(start));
                     fnStart = 0;
                 } else if (isConstOp(opCode)) {
+                    if (errorLatch)
+                        return false;
+
                     assert(asId(start + 2) != spv::NoResult);
                     typeConstPos.insert(start);
                 } else if (isTypeOp(opCode)) {
@@ -451,18 +492,24 @@ namespace spv {
     {
         msg(2, 2, std::string("validating: "));
 
-        if (spv.size() < header_size)
+        if (spv.size() < header_size) {
             error("file too short: ");
+            return;
+        }
 
-        if (magic() != spv::MagicNumber)
+        if (magic() != spv::MagicNumber) {
             error("bad magic number");
+            return;
+        }
 
         // field 1 = version
         // field 2 = generator magic
         // field 3 = result <id> bound
 
-        if (schemaNum() != 0)
+        if (schemaNum() != 0) {
             error("bad schema, must be 0");
+            return;
+        }
     }
 
     int spirvbin_t::processInstruction(unsigned word, instfn_t instFn, idfn_t idFn)
@@ -472,8 +519,10 @@ namespace spv {
         const int      nextInst  = word++ + wordCount;
         spv::Op  opCode    = asOpCode(instructionStart);
 
-        if (nextInst > int(spv.size()))
+        if (nextInst > int(spv.size())) {
             error("spir instruction terminated too early");
+            return -1;
+        }
 
         // Base for computing number of operands; will be updated as more is learned
         unsigned numOperands = wordCount - 1;
@@ -555,6 +604,9 @@ namespace spv {
                     const unsigned literalSize = idTypeSizeInWords(idBuffer[literalSizePos]);
                     const unsigned numLiteralIdPairs = (nextInst-word) / (1+literalSize);
 
+                    if (errorLatch)
+                        return -1;
+
                     for (unsigned arg=0; arg<numLiteralIdPairs; ++arg) {
                         word += literalSize;  // literal
                         idFn(asId(word++));   // label
@@ -631,9 +683,13 @@ namespace spv {
         // basic parsing and InstructionDesc table borrowed from SpvDisassemble.cpp...
         unsigned nextInst = unsigned(spv.size());
 
-        for (unsigned word = begin; word < end; word = nextInst)
+        for (unsigned word = begin; word < end; word = nextInst) {
             nextInst = processInstruction(word, instFn, idFn);
 
+            if (errorLatch)
+                return *this;
+        }
+
         return *this;
     }
 
@@ -648,8 +704,11 @@ namespace spv {
             for (const char c : name.first)
                 hashval = hashval * 1009 + c;
 
-            if (isOldIdUnmapped(name.second))
+            if (isOldIdUnmapped(name.second)) {
                 localId(name.second, nextUnusedId(hashval % softTypeIdLimit + firstMappedID));
+                if (errorLatch)
+                    return;
+            }
         }
     }
 
@@ -671,6 +730,9 @@ namespace spv {
             [&](spv::Op, unsigned start) { instPos.push_back(start); return true; },
             op_fn_nop);
 
+        if (errorLatch)
+            return;
+
         // Window size for context-sensitive canonicalization values
         // Empirical best size from a single data set.  TODO: Would be a good tunable.
         // We essentially perform a little convolution around each instruction,
@@ -706,8 +768,12 @@ namespace spv {
                         hashval = hashval * 30103 + asOpCodeHash(instPos[i]); // 30103 = semiarbitrary prime
                     }
 
-                    if (isOldIdUnmapped(resId))
+                    if (isOldIdUnmapped(resId)) {
                         localId(resId, nextUnusedId(hashval % softTypeIdLimit + firstMappedID));
+                        if (errorLatch)
+                            return;
+                    }
+
                 }
             }
         }
@@ -800,6 +866,9 @@ namespace spv {
             [&](spv::Id& id) { if (idMap.find(id) != idMap.end()) id = idMap[id]; }
         );
 
+        if (errorLatch)
+            return;
+
         // EXPERIMENTAL: Implicit output stores
         fnLocalVars.clear();
         idMap.clear();
@@ -820,11 +889,17 @@ namespace spv {
             },
             op_fn_nop);
 
+        if (errorLatch)
+            return;
+
         process(
             inst_fn_nop,
             [&](spv::Id& id) { if (idMap.find(id) != idMap.end()) id = idMap[id]; }
         );
 
+        if (errorLatch)
+            return;
+
         strip();          // strip out data we decided to eliminate
     }
 
@@ -924,6 +999,9 @@ namespace spv {
             }
         );
 
+        if (errorLatch)
+            return;
+
         process(
             [&](spv::Op opCode, unsigned start) {
                 if (opCode == spv::OpLoad && fnLocalVars.count(asId(start+3)) > 0)
@@ -932,6 +1010,9 @@ namespace spv {
             },
             op_fn_nop);
 
+        if (errorLatch)
+            return;
+
         // Chase replacements to their origins, in case there is a chain such as:
         //   2 = store 1
         //   3 = load 2
@@ -965,6 +1046,9 @@ namespace spv {
             }
         );
 
+        if (errorLatch)
+            return;
+
         strip();          // strip out data we decided to eliminate
     }
 
@@ -1008,6 +1092,9 @@ namespace spv {
                         fn->second.first,
                         fn->second.second);
 
+                    if (errorLatch)
+                        return;
+
                     fn = fnPos.erase(fn);
                 } else ++fn;
             }
@@ -1040,6 +1127,9 @@ namespace spv {
             [&](spv::Id& id) { if (varUseCount[id]) ++varUseCount[id]; }
         );
 
+        if (errorLatch)
+            return;
+
         // Remove single-use function variables + associated decorations and names
         process(
             [&](spv::Op opCode, unsigned start) {
@@ -1081,6 +1171,9 @@ namespace spv {
                     [&](spv::Id& id) { if (isType[id]) ++typeUseCount[id]; }
                     );
 
+            if (errorLatch)
+                return;
+
             // Remove single reference types
             for (const auto typeStart : typeConstPos) {
                 const spv::Id typeId = asTypeConstId(typeStart);
@@ -1090,6 +1183,9 @@ namespace spv {
                     stripInst(typeStart);
                 }
             }
+
+            if (errorLatch)
+                return;
         }
     }
 
@@ -1168,8 +1264,10 @@ namespace spv {
     unsigned spirvbin_t::idPos(spv::Id id) const
     {
         const auto tid_it = idPosR.find(id);
-        if (tid_it == idPosR.end())
+        if (tid_it == idPosR.end()) {
             error("ID not found");
+            return 0;
+        }
 
         return tid_it->second;
     }
@@ -1268,8 +1366,14 @@ namespace spv {
             const spv::Id       resId     = asTypeConstId(typeStart);
             const std::uint32_t hashval   = hashType(typeStart);
 
-            if (isOldIdUnmapped(resId))
+            if (errorLatch)
+                return;
+
+            if (isOldIdUnmapped(resId)) {
                 localId(resId, nextUnusedId(hashval % softTypeIdLimit + firstMappedID));
+                if (errorLatch)
+                    return;
+            }
         }
     }
 
@@ -1315,24 +1419,49 @@ namespace spv {
         msg(3, 4, std::string("ID bound: ") + std::to_string(bound()));
 
         if (options & STRIP)         stripDebug();
-        strip();        // strip out data we decided to eliminate
+        if (errorLatch) return;
-        if (options & OPT_LOADSTORE) optLoadStore();
-        if (options & OPT_FWD_LS)    forwardLoadStores();
-        if (options & DCE_FUNCS)     dceFuncs();
-        if (options & DCE_VARS)      dceVars();
-        if (options & DCE_TYPES)     dceTypes();
 
         strip();        // strip out data we decided to eliminate
+        if (errorLatch) return;
+
+        if (options & OPT_LOADSTORE) optLoadStore();
+        if (errorLatch) return;
+
+        if (options & OPT_FWD_LS)    forwardLoadStores();
+        if (errorLatch) return;
+
+        if (options & DCE_FUNCS)     dceFuncs();
+        if (errorLatch) return;
+
+        if (options & DCE_VARS)      dceVars();
+        if (errorLatch) return;
+
+        if (options & DCE_TYPES)     dceTypes();
+        if (errorLatch) return;
+
+        strip();         // strip out data we decided to eliminate
+        if (errorLatch) return;
+
         stripDeadRefs(); // remove references to things we DCEed
+        if (errorLatch) return;
+
         // after the last strip, we must clean any debug info referring to now-deleted data
 
         if (options & MAP_TYPES)     mapTypeConst();
+        if (errorLatch) return;
+
         if (options & MAP_NAMES)     mapNames();
+        if (errorLatch) return;
+
         if (options & MAP_FUNCS)     mapFnBodies();
+        if (errorLatch) return;
 
         if (options & MAP_ALL) {
             mapRemainder(); // map any unmapped IDs
+            if (errorLatch) return;
+
             applyMap();     // Now remap each shader to the new IDs we've come up with
+            if (errorLatch) return;
         }
     }
 

SPIRV/SPVRemapper.h

@@ -39,6 +39,7 @@
 #include <string>
 #include <vector>
 #include <cstdlib>
+#include <exception>
 
 namespace spv {
 
@@ -111,7 +112,9 @@ namespace spv {
 class spirvbin_t : public spirvbin_base_t
 {
 public:
-   spirvbin_t(int verbose = 0) : entryPoint(spv::NoResult), largestNewId(0), verbose(verbose) { }
+   spirvbin_t(int verbose = 0) : entryPoint(spv::NoResult), largestNewId(0), verbose(verbose), errorLatch(false)
+   { }
+
    virtual ~spirvbin_t() { }
 
    // remap on an existing binary in memory
@@ -165,7 +168,7 @@ private:
    typedef std::unordered_map<spv::Id, unsigned> typesize_map_t;
 
    // handle error
-   void error(const std::string& txt) const { errorHandler(txt); }
+   void error(const std::string& txt) const { errorLatch = true; errorHandler(txt); }
 
    bool     isConstOp(spv::Op opCode)      const;
    bool     isTypeOp(spv::Op opCode)       const;
@@ -286,6 +289,11 @@ private:
    std::uint32_t options;
    int           verbose;     // verbosity level
 
+   // Error latch: this is set if the error handler is ever executed.  It would be better to
+   // use a try/catch block and throw, but that's not desired for certain environments, so
+   // this is the alternative.
+   mutable bool errorLatch;
+
    static errorfn_t errorHandler;
    static logfn_t   logHandler;
 };

Test/baseResults/remap.invalid-spirv-1.out

@@ -0,0 +1 @@
+ID out of range: 4160749568

Test/baseResults/remap.invalid-spirv-2.out

@@ -0,0 +1 @@
+ID not found

Test/runtests

@@ -3,6 +3,7 @@
 TARGETDIR=localResults
 BASEDIR=baseResults
 EXE=../build/install/bin/glslangValidator
+REMAPEXE=../build/install/bin/spirv-remap
 HASERROR=0
 mkdir -p localResults
 
@@ -141,6 +142,7 @@ diff -b $BASEDIR/hlsl.dashI.vert.out $TARGETDIR/hlsl.dashI.vert.out || HASERROR=
 #
 # Testing -D and -U
 #
+echo "Testing -D and -U"
 $EXE -DUNDEFED -UIN_SHADER -DFOO=200 -i -l -UUNDEFED -DMUL=FOO*2 glsl.-D-U.frag > $TARGETDIR/glsl.-D-U.frag.out
 diff -b $BASEDIR/glsl.-D-U.frag.out $TARGETDIR/glsl.-D-U.frag.out || HASERROR=1
 $EXE -D -e main -V -i -DUNDEFED -UIN_SHADER -DFOO=200 -UUNDEFED hlsl.-D-U.frag > $TARGETDIR/hlsl.-D-U.frag.out
@@ -149,6 +151,7 @@ diff -b $BASEDIR/hlsl.-D-U.frag.out $TARGETDIR/hlsl.-D-U.frag.out || HASERROR=1
 #
 # Test --client and --target-env
 #
+echo "Testing --client and --target-env"
 $EXE --client vulkan100      spv.targetVulkan.vert || HASERROR=1
 $EXE --client opengl100      spv.targetOpenGL.vert || HASERROR=1
 $EXE --target-env vulkan1.0  spv.targetVulkan.vert || HASERROR=1
@@ -159,6 +162,7 @@ $EXE -G100                   spv.targetOpenGL.vert || HASERROR=1
 #
 # Testing GLSL entry point rename
 #
+echo "Testing GLSL entry point rename"
 $EXE -H -e foo --source-entrypoint main glsl.entryPointRename.vert > $TARGETDIR/glsl.entryPointRename.vert.out
 diff -b $BASEDIR/glsl.entryPointRename.vert.out $TARGETDIR/glsl.entryPointRename.vert.out || HASERROR=1
 $EXE -H -e foo --source-entrypoint bar glsl.entryPointRename.vert > $TARGETDIR/glsl.entryPointRename.vert.bad.out
@@ -166,6 +170,15 @@ diff -b $BASEDIR/glsl.entryPointRename.vert.bad.out $TARGETDIR/glsl.entryPointRe
 $EXE -H -e foo --source-entrypoint main glsl.entryPointRename2.vert > $TARGETDIR/glsl.entryPointRename2.vert.out
 diff -b $BASEDIR/glsl.entryPointRename2.vert.out $TARGETDIR/glsl.entryPointRename2.vert.out || HASERROR=1
 
+#
+# Testing remapper error handling
+#
+echo "Testing remapper error handling"
+$REMAPEXE --do-everything -i remap.invalid-spirv-1.spv -o $TARGETDIR > $TARGETDIR/remap.invalid-spirv-1.out && HASERROR=1
+diff -b $BASEDIR/remap.invalid-spirv-1.out $TARGETDIR/remap.invalid-spirv-1.out || HASERROR=1
+$REMAPEXE --do-everything -i remap.invalid-spirv-2.spv -o $TARGETDIR > $TARGETDIR/remap.invalid-spirv-2.out && HASERROR=1
+diff -b $BASEDIR/remap.invalid-spirv-2.out $TARGETDIR/remap.invalid-spirv-2.out || HASERROR=1
+
 #
 # Final checking
 #