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[RuntimeDyld] Fix conservative over-allocation of memory for common symbols. 

The previous allocation code was over-estimating the amount of memory required.

No test case: we don't currently have a good way to detect conervative
over-allocation.

llvm-svn: 267041
This commit is contained in:
Lang Hames 2016-04-21 20:08:06 +00:00
parent ad2d8f3dfd
commit 543e0dcc0a
1 changed files with 14 additions and 4 deletions
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18
llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
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@ -397,17 +397,24 @@ void RuntimeDyldImpl::computeTotalAllocSize(const ObjectFile &Obj,
// Compute the size of all common symbols
uint64_t CommonSize = 0;
uint32_t CommonAlign = 1;
for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E;
++I) {
uint32_t Flags = I->getFlags();
if (Flags & SymbolRef::SF_Common) {
// Add the common symbols to a list. We'll allocate them all below.
uint64_t Size = I->getCommonSize();
CommonSize += Size;
uint32_t Align = I->getAlignment();
// If this is the first common symbol, use its alignment as the alignment
// for the common symbols section.
if (CommonSize == 0)
CommonAlign = Align;
CommonSize = alignTo(CommonSize, Align) + Size;
}
}
if (CommonSize != 0) {
RWSectionSizes.push_back(CommonSize);
RWDataAlign = std::max(RWDataAlign, CommonAlign);
}
// Compute the required allocation space for each different type of sections
@ -491,6 +498,7 @@ void RuntimeDyldImpl::emitCommonSymbols(const ObjectFile &Obj,
return;
uint64_t CommonSize = 0;
uint32_t CommonAlign = CommonSymbols.begin()->getAlignment();
CommonSymbolList SymbolsToAllocate;
DEBUG(dbgs() << "Processing common symbols...\n");
@ -511,14 +519,16 @@ void RuntimeDyldImpl::emitCommonSymbols(const ObjectFile &Obj,
uint32_t Align = Sym.getAlignment();
uint64_t Size = Sym.getCommonSize();
CommonSize += Align + Size;
CommonSize = alignTo(CommonSize, Align) + Size;
SymbolsToAllocate.push_back(Sym);
}
// Allocate memory for the section
unsigned SectionID = Sections.size();
uint8_t *Addr = MemMgr.allocateDataSection(CommonSize, sizeof(void *),
SectionID, StringRef(), false);
uint8_t *Addr = MemMgr.allocateDataSection(CommonSize, CommonAlign,
SectionID, "<common symbols>",
false);
if (!Addr)
report_fatal_error("Unable to allocate memory for common symbols!");
uint64_t Offset = 0;