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* Revise the Stacking pass and its proof to make it easier to adapt to 64-bit ↵Xavier Leroy2016-04-271-1/+21
| | | | | | | | | | | | | | | | | | | architectures The original Stacking pass and its proof hard-wire assumptions about the processor and the register allocation, namely that integer registers are 32 bit wide and that all stack slots have natural alignment 4, which precludes having stack slots of type Tlong. Those assumptions become false if the target processor has 64-bit integer registers. This commit makes minimal adjustments to the Stacking pass so as to lift these assumptions: - Stack slots of type Tlong (or more generally of natural alignment 8) are supported. For slots produced by register allocation, the alignment is validated a posteriori in Lineartyping. For slots produced by the calling conventions, alignment is proved as part of the "loc_argument_acceptable" property in Conventions1. - The code generated by Stacking to save and restore used callee-save registers no longer assumes 32-bit integer registers. Actually, it supports any combination of sizes for registers. - To support the new save/restore code, Bounds was changed to record the set of all callee-save registers used, rather than just the max index of callee-save registers used. On CompCert's current 32-bit target architectures, the new Stacking pass should generate pretty much the same code as the old one, modulo minor differences in the layout of the stack frame. (E.g. padding could be introduced at different places.) The bulk of this big commit is related to the proof of the Stacking phase. The old proof strategy was painful and not obviously adaptable to the new Stacking phase, so I rewrote Stackingproof entirely, using an approach inspired by separation logic. The new library common/Separation.v defines assertions about memory states that can be composed using a separating conjunction, just like pre- and post-conditions in separation logic. Those assertions are used in Stackingproof to describe the contents of the stack frames during the execution of the generated Mach code, and relate them with the Linear location maps. As a further simplification, the callee-save/caller-save distinction is now defined in Conventions1 by a function is_callee_save: mreg -> bool, instead of lists of registers of either kind as before. This eliminates many boring classification lemmas from Conventions1. LTL and Lineartyping were adapted accordingly. Finally, this commit introduces a new library called Decidableplus to prove some propositions by reflection as Boolean computations. It is used to further simplify the proofs in Conventions1.
* Updated PR by removing whitespaces. Bug 17450.Bernhard Schommer2015-10-201-1/+1
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* Use Coq strings instead of idents to name external and builtin functions.Xavier Leroy2015-10-111-15/+8
| | | | | | | | | | The AST.ident type represents source-level identifiers as unique positive numbers. However, the mapping identifiers <-> AST.ident differs between runs of CompCert on different source files. This is problematic when we need to produce or recognize external functions and builtin functions with fixed names, for example: * in $ARCH/Machregs.v to define the register conventions for builtin functions; * in the VST program logic from Princeton to treat thread primitives specially. So far, we used AST.ident_of_string to recover the ident associated with a string. However, this function is defined in OCaml and doesn't execute within Coq. This is a problem both for VST and for future executability of CompCert within Coq. This commit replaces "ident" by "string" in the arguments of EF_external, EF_builtin, EF_inline_asm, EF_annot, and EF_annot_val. This provides stable names for externals and builtins, as needed. For inline asm and annotations, it's a matter of taste, but using strings feels more natural. EF_debug keeps using idents, since some kinds of EF_debug annotations talk about program variables.
* Refactoring of builtins and annotations in the back-end.Xavier Leroy2015-08-211-1/+12
| | | | | | | | | | | | | | | | | | | | | | | | Before, the back-end languages had distinct instructions - Iannot for annotations, taking structured expressions (annot_arg) as arguments, and producing no results' - Ibuiltin for other builtins, using simple pseudoregs/locations/registers as arguments and results. This branch enriches Ibuiltin instructions so that they take structured expressions (builtin_arg and builtin_res) as arguments and results. This way, - Annotations fit the general pattern of builtin functions, so Iannot instructions are removed. - EF_vload_global and EF_vstore_global become useless, as the same optimization can be achieved by EF_vload/vstore taking a structured argument of the "address of global" kind. - Better code can be generated for builtin_memcpy between stack locations, or volatile accesses to stack locations. Finally, this commit also introduces a new kind of external function, EF_debug, which is like EF_annot but produces no observable events. It will be used later to transport debug info through the back-end, without preventing optimizations.
* Extended inline asm: revised treatment of clobbered registers.Xavier Leroy2015-05-091-1/+29
| | | | | | | | | | - Treat clobbered registers as being destroyed by EF_inline_asm builtins (which is the truth, semantically). - To enable the above, represent clobbers as Coq strings rather than idents and move register_by_name from Machregsaux.ml to Machregs.v. - Side benefit: more efficient implementation of Machregsaux.name_of_register. -# Please enter the commit message for your changes. Lines starting
* Merge of "newspilling" branch:xleroy2014-07-231-14/+16
| | | | | | | | | | | | | | | - Support single-precision floats as first-class values - Introduce chunks Many32, Many64 and types Tany32, Tany64 to support saving and restoring registers without knowing the exact types (int/single/float) of their contents, just their sizes. - Memory model: generalize the opaque encoding of pointers to apply to any value, not just pointers, if chunks Many32/Many64 are selected. - More properties of FP arithmetic proved. git-svn-id: https://yquem.inria.fr/compcert/svn/compcert/trunk@2537 fca1b0fc-160b-0410-b1d3-a4f43f01ea2e
* Support Onot operator / notl instruction. More constant propagation during ↵xleroy2014-04-061-0/+1
| | | | | | selection. git-svn-id: https://yquem.inria.fr/compcert/svn/compcert/trunk@2451 fca1b0fc-160b-0410-b1d3-a4f43f01ea2e
* In Regalloc, dead code elimination, don't eliminate move operationsxleroy2014-02-231-0/+3
| | | | | | | | that pop the x87 FP stack (var <- FP0). Otherwise, (void) f(); where f returns a float eventually produces a FP stack overflow. git-svn-id: https://yquem.inria.fr/compcert/svn/compcert/trunk@2416 fca1b0fc-160b-0410-b1d3-a4f43f01ea2e
* - Back to origins: suppress Mfloat64al32 chunk and align Mfloat64 to 4.xleroy2014-01-121-1/+1
| | | | | | | - Revised printing of intermediate RTL code. git-svn-id: https://yquem.inria.fr/compcert/svn/compcert/trunk@2403 fca1b0fc-160b-0410-b1d3-a4f43f01ea2e
* Optimize integer divisions by positive constants, turning them intoxleroy2013-07-291-0/+6
| | | | | | | multiply-high and shifts. git-svn-id: https://yquem.inria.fr/compcert/svn/compcert/trunk@2300 fca1b0fc-160b-0410-b1d3-a4f43f01ea2e
* Merge of the float32 branch: xleroy2013-05-191-1/+8
| | | | | | | | - added RTL type "Tsingle" - ABI-compatible passing of single-precision floats on ARM and x86 git-svn-id: https://yquem.inria.fr/compcert/svn/compcert/trunk@2260 fca1b0fc-160b-0410-b1d3-a4f43f01ea2e
* Revert suppression of __builtin_{read,write}_reversed for x86 and ARM,xleroy2013-04-291-2/+9
| | | | | | | | for compatibility with earlier CompCert versions. But don't use them in PackedStructs. git-svn-id: https://yquem.inria.fr/compcert/svn/compcert/trunk@2216 fca1b0fc-160b-0410-b1d3-a4f43f01ea2e
* Add __builtin_bswap16 and __builtin_bswap32 to all ports.xleroy2013-04-201-5/+5
| | | | | | | | | Remove __builtin_{read,write}_reversed from IA32 and ARM ports. Machregs: tighten destroyed_by_builtin Packedstructs: use bswap if read/write-reversed not available. git-svn-id: https://yquem.inria.fr/compcert/svn/compcert/trunk@2208 fca1b0fc-160b-0410-b1d3-a4f43f01ea2e
* Big merge of the newregalloc-int64 branch. Lots of changes in two directions:xleroy2013-04-201-27/+165
| | | | | | | | | 1- new register allocator (+ live range splitting, spilling&reloading, etc) based on a posteriori validation using the Rideau-Leroy algorithm 2- support for 64-bit integer arithmetic (type "long long"). git-svn-id: https://yquem.inria.fr/compcert/svn/compcert/trunk@2200 fca1b0fc-160b-0410-b1d3-a4f43f01ea2e
* Glasnost: making transparent a number of definitions that were opaquexleroy2013-03-101-1/+2
| | | | | | | | for no good reason. git-svn-id: https://yquem.inria.fr/compcert/svn/compcert/trunk@2140 fca1b0fc-160b-0410-b1d3-a4f43f01ea2e
* Merge of the reuse-temps branch:xleroy2010-09-021-0/+76
- Reload temporaries are marked as destroyed (set to Vundef) across operations in the semantics of LTL, LTLin, Linear and Mach, allowing Asmgen to reuse them. - Added IA32 port. - Cleaned up float conversions and axiomatization of floats. git-svn-id: https://yquem.inria.fr/compcert/svn/compcert/trunk@1499 fca1b0fc-160b-0410-b1d3-a4f43f01ea2e