Recompute layout until symbol values converge#944
Recompute layout until symbol values converge#944parth-07 wants to merge 1 commit intoqualcomm:mainfrom
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This commit modifies the layout step to recompute layout until the symbol values converge. The reiteration has an upper-limit of 4. On reaching this limit, a note is emitted and layout reiteration is stopped. Please note that this reiteration limit is for layout iterations before relaxations take place. After a layout relaxation pass, the reiteration count is reset to 0. Resolves qualcomm#943 Signed-off-by: Parth Arora <partaror@qti.qualcomm.com>
| const llvm::StringMap<ResolveInfo *> &Globals = | ||
| m_Module.getNamePool().getGlobals(); | ||
| for (const auto &Entry : Globals) { | ||
| const ResolveInfo *RI = Entry.second; |
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We should not be comparing the symbol values of global symbols, as you can clearly see that local symbols are missing.
Can we check for fragment address instead ?
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I thought about it. I believe that just comparing the linker script symbols is enough. If all the linker script symbols and the output section address converge, then all the section-relative symbols will also converge. Please let me know your thoughts on this.
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interesting observation. Would this capture bumping alignment using dot inside output sections ?
| m_Module.getNamePool().getGlobals(); | ||
| for (const auto &Entry : Globals) { | ||
| const ResolveInfo *RI = Entry.second; | ||
| ASSERT(RI, "Must not be null!"); |
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Is this assert needed ?
| // Capture current layout snapshot keyed by OutputSectionEntry*. | ||
| LayoutSnapshot captureLayoutSnapshot() const; | ||
| struct DivergenceResult { | ||
| const OutputSectionEntry *section = nullptr; |
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section -> output section
| continue; | ||
| const LDSymbol *Sym = RI->outSymbol(); | ||
| if (Sym->scriptDefined()) | ||
| Result.push_back(Sym); |
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It would be useful to show the expression in the diagnostic instead of symbol, that will allow users do diagnose the problem better.
| LayoutSnapshot &S, | ||
| const std::vector<const LDSymbol *> &ScriptDefinedSymbols) const { | ||
| for (const LDSymbol *Sym : ScriptDefinedSymbols) | ||
| S.symbolValues.insert({Sym, Sym->value()}); |
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Does this work for provide as well ? because the symbols are not defined
| << S->name() << maxIterations; | ||
| } else if (diverged.symbol) { | ||
| config().raise(Diag::note_symbol_value_not_converging) | ||
| << diverged.symbol->name() << maxIterations; |
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print the symbol, section information and the input file/ input linker script
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This commit modifies the layout step to recompute layout until the symbol values converge. The reiteration has an upper-limit of 4. On reaching this limit, a note is emitted and layout reiteration is stopped.
Please note that this reiteration limit is for layout iterations before relaxations take place. After a layout relaxation pass, the reiteration count is reset to 0.
Resolves #943