From 2abb5af8b0baf90afa8ab751d2a3e658cd17c4d8 Mon Sep 17 00:00:00 2001
From: chrisly42 <chrisly@platon42.de>
Date: Thu, 5 Aug 2021 16:21:32 +0200
Subject: [PATCH] Macros with register name now abort Dead Write analysis. Fix
 for modifying statements extending the with of the written data.

---
 .../inspections/M68kDeadWriteInspection.kt    |  8 +++-
 .../inspectionDescriptions/M68kDeadWrite.html |  5 ++-
 .../M68kDeadWriteInspectionTest.kt            | 39 +++++++++++++++++++
 3 files changed, 50 insertions(+), 2 deletions(-)

diff --git a/src/main/java/de/platon42/intellij/plugins/m68k/inspections/M68kDeadWriteInspection.kt b/src/main/java/de/platon42/intellij/plugins/m68k/inspections/M68kDeadWriteInspection.kt
index 47fc815..971cd51 100644
--- a/src/main/java/de/platon42/intellij/plugins/m68k/inspections/M68kDeadWriteInspection.kt
+++ b/src/main/java/de/platon42/intellij/plugins/m68k/inspections/M68kDeadWriteInspection.kt
@@ -48,7 +48,7 @@ class M68kDeadWriteInspection : AbstractBaseM68kLocalInspectionTool() {
         val hints = SmartList<ProblemDescriptor>()
         for (regPair in regsWritten) {
             val register = regPair.first
-            val rwm = regPair.second
+            var rwm = regPair.second
             var currStatement = asmInstruction.parent as M68kStatement
 
             var ccModification = adrMode.affectedCc
@@ -61,6 +61,11 @@ class M68kDeadWriteInspection : AbstractBaseM68kLocalInspectionTool() {
                 val globalLabel = PsiTreeUtil.findChildOfType(currStatement, M68kGlobalLabel::class.java)
                 if (globalLabel != null) break
                 if (PsiTreeUtil.getChildOfType(currStatement, M68kPreprocessorDirective::class.java) != null) break
+
+                // as we cannot evaluate macros right now, abort at macros containing the register name (only lower case for simplicity)
+                val macroCall = PsiTreeUtil.getChildOfType(currStatement, M68kMacroCall::class.java)
+                if (macroCall?.exprList?.any { it.textMatches(register.regname) } == true) break
+
                 val currAsmInstruction = PsiTreeUtil.getChildOfType(currStatement, M68kAsmInstruction::class.java) ?: continue
                 val (isaData, currAdrMode) = findExactIsaDataAndAllowedAdrModeForInstruction(currAsmInstruction) ?: continue
                 if (isaData.changesControlFlow) break
@@ -74,6 +79,7 @@ class M68kDeadWriteInspection : AbstractBaseM68kLocalInspectionTool() {
                         hasModification = true
                         ccOverwritten = false
                         ccModification = ccModification or currAdrMode.affectedCc
+                        rwm = (totalRwms ushr RWM_MODIFY_SHIFT) and RWM_SET_L
                     }
                     if (totalRwms and RWM_SET_L >= rwm) {
                         if (ccTested && hasModification) {
diff --git a/src/main/resources/inspectionDescriptions/M68kDeadWrite.html b/src/main/resources/inspectionDescriptions/M68kDeadWrite.html
index 5d36d20..efb8481 100644
--- a/src/main/resources/inspectionDescriptions/M68kDeadWrite.html
+++ b/src/main/resources/inspectionDescriptions/M68kDeadWrite.html
@@ -7,6 +7,9 @@ Issues a weak warning if the instruction affects only condition codes that are l
 Analysis is terminated at the next global label or instruction that reads the register or changes control flow
 (or preprocessor statements, like conditional IF statements).
 <!-- tooltip end -->
-<p>Note: As there is no evaluation of macros right now, the inspection might report some false positives.</p>
+<p>Note: As there is no evaluation of macros right now, the inspection might report some false positives.
+
+    As an attempt to reduce these false positives, macros containing the register name will abort the analysis.
+</p>
 </body>
 </html>
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diff --git a/src/test/java/de/platon42/intellij/plugins/m68k/inspections/M68kDeadWriteInspectionTest.kt b/src/test/java/de/platon42/intellij/plugins/m68k/inspections/M68kDeadWriteInspectionTest.kt
index fb5815a..961a53b 100644
--- a/src/test/java/de/platon42/intellij/plugins/m68k/inspections/M68kDeadWriteInspectionTest.kt
+++ b/src/test/java/de/platon42/intellij/plugins/m68k/inspections/M68kDeadWriteInspectionTest.kt
@@ -169,4 +169,43 @@ internal class M68kDeadWriteInspectionTest : AbstractInspectionTest() {
         )
         assertThat(myFixture.doHighlighting()).isEmpty()
     }
+
+    @Test
+    internal fun modification_extending_width_does_not_cause_a_warning_on_smaller_write_later(@MyFixture myFixture: CodeInsightTestFixture) {
+        myFixture.enableInspections(M68kDeadWriteInspection::class.java)
+        myFixture.configureByText(
+            "deadwrite.asm", """
+	move.b  (a0)+,d0
+	lsl     #8,d0
+	move.b  (a0)+,d0
+        """
+        )
+        assertThat(myFixture.doHighlighting()).isEmpty()
+    }
+
+    @Test
+    internal fun macro_call_with_register_name_will_not_cause_a_warning(@MyFixture myFixture: CodeInsightTestFixture) {
+        myFixture.enableInspections(M68kDeadWriteInspection::class.java)
+        myFixture.configureByText(
+            "deadwrite.asm", """
+    moveq.l #-1,d0
+    COPRMOVE d0,bltafwm
+    move.l  pd_CurrPlanesPtr(a4),d0
+        """
+        )
+        assertThat(myFixture.doHighlighting()).isEmpty()
+    }
+
+    @Test
+    internal fun macro_call_with_different_register_name_will_cause_a_warning(@MyFixture myFixture: CodeInsightTestFixture) {
+        myFixture.enableInspections(M68kDeadWriteInspection::class.java)
+        myFixture.configureByText(
+            "deadwrite.asm", """
+    moveq.l #-1,d0
+    COPRMOVE d1,bltafwm
+    move.l  pd_CurrPlanesPtr(a4),d0
+        """
+        )
+        assertHighlightings(myFixture, 1, "Register d0 is overwritten later without being used")
+    }
 }
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