Widen EHScope::ClenupBitFields::FixupDepth to avoid overflowing it (PR23490)
It currently only takes 2048 gotos to overflow the FixupDepth bitfield,
causing silent miscompilation. Apparently some parser generators run into
this (see PR).
I don't know that that data structure is terribly size sensitive anyway,
and since there's no room to widen the bitfield, let's just use a separate
word in EHCatchScope for it.
Differential Revision: http://reviews.llvm.org/D21566
llvm-svn: 273434
diff --git a/clang/lib/CodeGen/CGCleanup.h b/clang/lib/CodeGen/CGCleanup.h
index 4823773..98d01b1 100644
--- a/clang/lib/CodeGen/CGCleanup.h
+++ b/clang/lib/CodeGen/CGCleanup.h
@@ -86,11 +86,6 @@
/// The amount of extra storage needed by the Cleanup.
/// Always a multiple of the scope-stack alignment.
unsigned CleanupSize : 12;
-
- /// The number of fixups required by enclosing scopes (not including
- /// this one). If this is the top cleanup scope, all the fixups
- /// from this index onwards belong to this scope.
- unsigned FixupDepth : 32 - 18 - NumCommonBits; // currently 12
};
class FilterBitFields {
@@ -188,6 +183,7 @@
EHScopeStack::stable_iterator enclosingEHScope)
: EHScope(Catch, enclosingEHScope) {
CatchBits.NumHandlers = numHandlers;
+ assert(CatchBits.NumHandlers == numHandlers && "NumHandlers overflow?");
}
unsigned getNumHandlers() const {
@@ -263,6 +259,11 @@
};
mutable struct ExtInfo *ExtInfo;
+ /// The number of fixups required by enclosing scopes (not including
+ /// this one). If this is the top cleanup scope, all the fixups
+ /// from this index onwards belong to this scope.
+ unsigned FixupDepth;
+
struct ExtInfo &getExtInfo() {
if (!ExtInfo) ExtInfo = new struct ExtInfo();
return *ExtInfo;
@@ -288,8 +289,9 @@
unsigned cleanupSize, unsigned fixupDepth,
EHScopeStack::stable_iterator enclosingNormal,
EHScopeStack::stable_iterator enclosingEH)
- : EHScope(EHScope::Cleanup, enclosingEH), EnclosingNormal(enclosingNormal),
- NormalBlock(nullptr), ActiveFlag(nullptr), ExtInfo(nullptr) {
+ : EHScope(EHScope::Cleanup, enclosingEH),
+ EnclosingNormal(enclosingNormal), NormalBlock(nullptr),
+ ActiveFlag(nullptr), ExtInfo(nullptr), FixupDepth(fixupDepth) {
CleanupBits.IsNormalCleanup = isNormal;
CleanupBits.IsEHCleanup = isEH;
CleanupBits.IsActive = isActive;
@@ -297,7 +299,6 @@
CleanupBits.TestFlagInNormalCleanup = false;
CleanupBits.TestFlagInEHCleanup = false;
CleanupBits.CleanupSize = cleanupSize;
- CleanupBits.FixupDepth = fixupDepth;
assert(CleanupBits.CleanupSize == cleanupSize && "cleanup size overflow");
}
@@ -343,7 +344,7 @@
return CleanupBits.TestFlagInEHCleanup;
}
- unsigned getFixupDepth() const { return CleanupBits.FixupDepth; }
+ unsigned getFixupDepth() const { return FixupDepth; }
EHScopeStack::stable_iterator getEnclosingNormalCleanup() const {
return EnclosingNormal;
}
@@ -451,6 +452,7 @@
EHFilterScope(unsigned numFilters)
: EHScope(Filter, EHScopeStack::stable_end()) {
FilterBits.NumFilters = numFilters;
+ assert(FilterBits.NumFilters == numFilters && "NumFilters overflow");
}
static size_t getSizeForNumFilters(unsigned numFilters) {