DrNim (Nim compiler with Z3 integration) (#13743)

* code cleanups and feature additions
* added basic test and koch/CI integration
* make it build on Unix
* DrNim: now buildable on Unix, only takes 10 minutes, enjoy
* added basic documentation for DrNim which can also be seen as the RFC we're following
* drnim: change the build setup so that drnim.exe ends up in bin/
* makes simple floating point ranges work
* added basic float range check
* drnim: teach Z3 about Nim's range types plus code refactoring
* drnim: make unsigned numbers work
* added and fixed index checking under setLen
* first implementation of .ensures, .invariant and .assume (.requires still missing and so is proc type compatibility checking
* drnim: .requires checking implemented
* drnim: implemented .ensures properly
* more impressive test involving min()
* drnim: check for proc type compatibility and base method compatibility wrt .requires and .ensures
* testament: support for 'pattern <directory>
* koch: uses new <directory> feature of testament
* drnim: added tiny musings about 'old'
* Make testament work with old SSL versions
* koch: add support for 'koch drnim -d:release'
* drnim: preparations for the param.old notation

compiler/pragmas.nim

@@ -28,7 +28,8 @@ const
     wBorrow, wImportCompilerProc, wThread,
     wAsmNoStackFrame, wDiscardable, wNoInit, wCodegenDecl,
     wGensym, wInject, wRaises, wTags, wLocks, wDelegator, wGcSafe,
-    wConstructor, wLiftLocals, wStackTrace, wLineTrace, wNoDestroy}
+    wConstructor, wLiftLocals, wStackTrace, wLineTrace, wNoDestroy,
+    wRequires, wEnsures}
   converterPragmas* = procPragmas
   methodPragmas* = procPragmas+{wBase}-{wImportCpp}
   templatePragmas* = {wDeprecated, wError, wGensym, wInject, wDirty,
@@ -39,7 +40,7 @@ const
   iteratorPragmas* = declPragmas + {FirstCallConv..LastCallConv, wNoSideEffect, wSideEffect,
     wMagic, wBorrow,
     wDiscardable, wGensym, wInject, wRaises,
-    wTags, wLocks, wGcSafe}
+    wTags, wLocks, wGcSafe, wRequires, wEnsures}
   exprPragmas* = {wLine, wLocks, wNoRewrite, wGcSafe, wNoSideEffect}
   stmtPragmas* = {wChecks, wObjChecks, wFieldChecks, wRangeChecks,
     wBoundChecks, wOverflowChecks, wNilChecks, wStaticBoundchecks,
@@ -52,11 +53,12 @@ const
     wDeprecated,
     wFloatChecks, wInfChecks, wNanChecks, wPragma, wEmit, wUnroll,
     wLinearScanEnd, wPatterns, wTrMacros, wEffects, wNoForward, wReorder, wComputedGoto,
-    wInjectStmt, wExperimental, wThis, wUsed}
+    wInjectStmt, wExperimental, wThis, wUsed, wInvariant, wAssume}
   lambdaPragmas* = declPragmas + {FirstCallConv..LastCallConv,
     wNoSideEffect, wSideEffect, wNoreturn, wNosinks, wDynlib, wHeader,
     wThread, wAsmNoStackFrame,
-    wRaises, wLocks, wTags, wGcSafe, wCodegenDecl} - {wExportNims, wError, wUsed}  # why exclude these?
+    wRaises, wLocks, wTags, wRequires, wEnsures,
+    wGcSafe, wCodegenDecl} - {wExportNims, wError, wUsed}  # why exclude these?
   typePragmas* = declPragmas + {wMagic, wAcyclic,
     wPure, wHeader, wCompilerProc, wCore, wFinal, wSize, wShallow,
     wIncompleteStruct, wByCopy, wByRef,
@@ -73,7 +75,8 @@ const
     wIntDefine, wStrDefine, wBoolDefine, wCompilerProc, wCore}
   letPragmas* = varPragmas
   procTypePragmas* = {FirstCallConv..LastCallConv, wVarargs, wNoSideEffect,
-                      wThread, wRaises, wLocks, wTags, wGcSafe}
+                      wThread, wRaises, wLocks, wTags, wGcSafe,
+                      wRequires, wEnsures}
   forVarPragmas* = {wInject, wGensym}
   allRoutinePragmas* = methodPragmas + iteratorPragmas + lambdaPragmas
   enumFieldPragmas* = {wDeprecated}
@@ -105,6 +108,26 @@ proc invalidPragma*(c: PContext; n: PNode) =
 proc illegalCustomPragma*(c: PContext, n: PNode, s: PSym) =
   localError(c.config, n.info, "cannot attach a custom pragma to '" & s.name.s & "'")
 
+proc pragmaProposition(c: PContext, n: PNode) =
+  if n.kind notin nkPragmaCallKinds or n.len != 2:
+    localError(c.config, n.info, "proposition expected")
+  else:
+    n[1] = c.semExpr(c, n[1])
+
+proc pragmaEnsures(c: PContext, n: PNode) =
+  if n.kind notin nkPragmaCallKinds or n.len != 2:
+    localError(c.config, n.info, "proposition expected")
+  else:
+    openScope(c)
+    let o = getCurrOwner(c)
+    if o.kind in routineKinds and o.typ != nil and o.typ.sons[0] != nil:
+      var s = newSym(skResult, getIdent(c.cache, "result"), o, n.info)
+      s.typ = o.typ.sons[0]
+      incl(s.flags, sfUsed)
+      addDecl(c, s)
+    n[1] = c.semExpr(c, n[1])
+    closeScope(c)
+
 proc pragmaAsm*(c: PContext, n: PNode): char =
   result = '\0'
   if n != nil:
@@ -1146,6 +1169,10 @@ proc singlePragma(c: PContext, sym: PSym, n: PNode, i: var int,
         if sym == nil: invalidPragma(c, it)
         else: sym.flags.incl sfUsed
       of wLiftLocals: discard
+      of wRequires, wInvariant, wAssume:
+        pragmaProposition(c, it)
+      of wEnsures:
+        pragmaEnsures(c, it)
       else: invalidPragma(c, it)
     elif comesFromPush and whichKeyword(ident) != wInvalid:
       discard "ignore the .push pragma; it doesn't apply"