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Add 0/1/2 warning levels to rgblink -Wtruncation (#1816)

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This commit is contained in:
Rangi
2025-09-01 15:35:53 -04:00
committed by GitHub
parent cc96b4d517
commit 534a4efee4
9 changed files with 90 additions and 28 deletions
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7
include/link/warning.hpp
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@@ -27,11 +27,14 @@ enum WarningID {
WARNING_OBSOLETE, // Obsolete/deprecated things
WARNING_SHIFT, // Undefined `SHIFT` behavior
WARNING_SHIFT_AMOUNT, // Strange `SHIFT` amount
WARNING_TRUNCATION, // Implicit truncation loses some bits
NB_PLAIN_WARNINGS,
NB_WARNINGS = NB_PLAIN_WARNINGS,
// Implicit truncation loses some bits
WARNING_TRUNCATION_1 = NB_PLAIN_WARNINGS,
WARNING_TRUNCATION_2,
NB_WARNINGS,
};
extern Diagnostics<WarningLevel, WarningID> warnings;

13
man/rgblink.1
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@@ -318,11 +318,20 @@ This warning is enabled by
Warn when a shift's operand is negative or greater than 32.
This warning is enabled by
.Fl Wall .
.It Fl Wno-truncation
.It Fl Wtruncation=
Warn when an implicit truncation (for example,
.Ic db
to an 8-bit value) loses some bits.
This occurs when an N-bit value is 2**N or greater, or less than -2**N.
.Fl Wtruncation=0
or
.Fl Wno-truncation
disables this warning.
.Fl Wtruncation=1
warns when an N-bit value is 2**N or greater, or less than -2**N.
.Fl Wtruncation=2
or just
.Fl Wtruncation
also warns when an N-bit value is less than -2**(N-1), which will not fit in two's complement encoding.
.El
.Sh EXAMPLES
All you need for a basic ROM is an object file, which can be made into a ROM image like so:

58
src/link/patch.cpp
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@@ -4,6 +4,7 @@
#include <deque>
#include <inttypes.h>
#include <limits.h>
#include <stdint.h>
#include <variant>
#include <vector>
@@ -503,6 +504,30 @@ void patch_CheckAssertions() {
}
}
static void checkPatchSize(Patch const &patch, int32_t v, uint8_t n) {
static constexpr unsigned m = CHAR_BIT * sizeof(int);
if (n < m && (v < -(1 << n) || v >= 1 << n)) {
diagnosticAt(
patch,
WARNING_TRUNCATION_1,
"Value $%" PRIx32 "%s is not %u-bit",
v,
v < 0 ? " (may be negative?)" : "",
n
);
return;
} else if (n < m + 1 && v < -(1 << (n - 1))) {
diagnosticAt(
patch,
WARNING_TRUNCATION_2,
"Value $%" PRIx32 "%s is not %u-bit",
v,
v < 0 ? " (may be negative?)" : "",
n
);
}
}
// Applies all of a section's patches to a data section
static void applyFilePatches(Section &section, Section &dataSection) {
verbosePrint(VERB_INFO, "Patching section \"%s\"...\n", section.name.c_str());
@@ -510,23 +535,19 @@ static void applyFilePatches(Section &section, Section &dataSection) {
int32_t value = computeRPNExpr(patch, *section.fileSymbols);
uint16_t offset = patch.offset + section.offset;
struct {
uint8_t size;
int32_t min;
int32_t max;
} const types[PATCHTYPE_INVALID] = {
{1, -128, 255 }, // PATCHTYPE_BYTE
{2, -32768, 65536 }, // PATCHTYPE_WORD
{4, INT32_MIN, INT32_MAX}, // PATCHTYPE_LONG
{1, 0, 0 }, // PATCHTYPE_JR
uint8_t typeSizes[PATCHTYPE_INVALID] = {
1, // PATCHTYPE_BYTE
2, // PATCHTYPE_WORD
4, // PATCHTYPE_LONG
1, // PATCHTYPE_JR
};
auto const &type = types[patch.type];
uint8_t typeSize = typeSizes[patch.type];
if (dataSection.data.size() < offset + type.size) {
if (dataSection.data.size() < offset + typeSize) {
errorAt(
patch,
"Patch would write %zu bytes past the end of section \"%s\" (%zu bytes long)",
offset + type.size - dataSection.data.size(),
offset + typeSize - dataSection.data.size(),
dataSection.name.c_str(),
dataSection.data.size()
);
@@ -547,17 +568,8 @@ static void applyFilePatches(Section &section, Section &dataSection) {
dataSection.data[offset] = jumpOffset & 0xFF;
} else {
// Patch a certain number of bytes
if (value < type.min || value > type.max) {
diagnosticAt(
patch,
WARNING_TRUNCATION,
"Value $%" PRIx32 "%s is not %u-bit",
value,
value < 0 ? " (may be negative?)" : "",
type.size * 8U
);
}
for (uint8_t i = 0; i < type.size; ++i) {
checkPatchSize(patch, value, typeSize * 8);
for (uint8_t i = 0; i < typeSize; ++i) {
dataSection.data[offset + i] = value & 0xFF;
value >>= 8;
}

6
src/link/warning.cpp
View File

@@ -26,9 +26,13 @@ Diagnostics<WarningLevel, WarningID> warnings = {
{"obsolete", LEVEL_DEFAULT },
{"shift", LEVEL_ALL },
{"shift-amount", LEVEL_ALL },
// Parametric warnings
{"truncation", LEVEL_DEFAULT },
{"truncation", LEVEL_EVERYTHING},
},
.paramWarnings = {
{WARNING_TRUNCATION_1, WARNING_TRUNCATION_2, 2},
},
.paramWarnings = {},
.state = DiagnosticsState<WarningID>(),
.nbErrors = 0,
};

16
test/link/test.sh
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@@ -439,6 +439,22 @@ rgblinkQuiet "$otemp" "$gbtemp" "$gbtemp2" "$outtemp" "$outtemp2" 2>"$outtemp3"
tryDiff "$test"/out.err "$outtemp3"
evaluateTest
test="truncation/level1"
startTest
"$RGBASM" -o "$otemp" "$test"/a.asm
continueTest
rgblinkQuiet -Wtruncation=1 -o "$gbtemp" "$otemp" 2>"$outtemp"
tryDiff "$test"/out.err "$outtemp"
evaluateTest
test="truncation/level2"
startTest
"$RGBASM" -o "$otemp" "$test"/a.asm
continueTest
rgblinkQuiet -Wtruncation=2 -o "$gbtemp" "$otemp" 2>"$outtemp"
tryDiff "$test"/out.err "$outtemp"
evaluateTest
if [[ "$failed" -eq 0 ]]; then
echo "${bold}${green}All ${tests} tests passed!${rescolors}${resbold}"
else

6
test/link/truncation/level1/a.asm Normal file
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@@ -0,0 +1,6 @@
section "rom", rom0
ld bc, -wLabel
ld de, -(wLabel * 2)
section "ram", wram0
wLabel::

2
test/link/truncation/level1/out.err Normal file
View File

@@ -0,0 +1,2 @@
warning: Value $fffe8000 (may be negative?) is not 16-bit [-Wtruncation]
at truncation/level1/a.asm(3)

6
test/link/truncation/level2/a.asm Normal file
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@@ -0,0 +1,6 @@
section "rom", rom0
ld bc, -wLabel
ld de, -(wLabel * 2)
section "ram", wram0
wLabel::

4
test/link/truncation/level2/out.err Normal file
View File

@@ -0,0 +1,4 @@
warning: Value $fffe8000 (may be negative?) is not 16-bit [-Wtruncation]
at truncation/level2/a.asm(3)
warning: Value $ffff4000 (may be negative?) is not 16-bit [-Wtruncation]
at truncation/level2/a.asm(2)